SCHOOL OF BIOMEDICAL AND ALLIED HEALTH SCIENCES 
COLLEGE OF HEALTH SCIENCES 
UNIVERSITY OF GHANA 
 
SERUM MAGNESIUM LEVEL AND RELATED BIOCHEMICAL PARAMETERS IN 
CARDIOVASCULAR DISEASES AT THE KORLE-BU TEACHING HOSPITAL 
 
BY 
MICHAEL AMEWONYE 
(10504897) 
 
 
THIS DISSERTATION IS SUBMITTED TO THE  
UNIVERSITY OF GHANA, LEGON IN PARTIAL FULFILMENT OF THE 
REQUIREMENT FOR THE AWARD OF MASTER OF SCIENCE IN MEDICAL 
LABORATORY SCIENCES DEGREE. 
 
 
JANUARY, 2018 
  
DECLARATION 
I declare that this thesis is my original work and has not been presented for any other awards at 
any other university. References to other people’s work have been duly acknowledged. This 
work was carried out in School of Biomedical and Allied Health Sciences, University of Ghana. 
 
 
……………………………..                                                ……………………………………. 
MICHAEL AMEWONYE                                                                              DATE                           
(STUDENT) 
 
 
……………………………..                                                ……………………………………… 
DR SETH D. AMANQUAH                                                                             DATE 
(SUPERVISOR) 
 
 
………………………………                                                   ………………………………… 
DR ALBERT AKPALU                                                                                      DATE 
(SUPERVISOR) 
 
 
 
i 
 
ABSTRACT 
Background: Serum magnesium (Mg) and other biochemical abnormalities in cardiovascular 
diseases (CVD) is a global concern as it has been implicated in CVD related morbidity and 
mortality. However, results from studies of these biochemical abnormalities especially of serum 
magnesium in CVDs are conflicting and unclear with no data on CVD patients at the Korle-Bu 
Teaching Hospital; hence the focus of the current study. 
Aim: To determine serum magnesium and related biochemical parameters in cardiovascular 
disease patients at the Korle-Bu Teaching Hospital. 
Method andMaterials: This research was a case-control study design with a convenience and 
systematic random sampling technique at the Department of Medicine and Therapeutics of the 
KBTH.  A total number of 128 participants including sixty (60) cases with various 
cardiovascular diseases and 68 control subjects were recruited after their informed consent and 
ethical clearance (SBAHS/10504897/AA/MLS/2015-2016) was obtained. Four (4) ml fasted 
blood samples were taken for biochemical analysis. Serum Mg, Ca, K, PO4, CK, HDL, LDH, 
and FBG were analyzed in the laboratory using dry Chemistry auto Analyzer (Vitrios 5.1 FS by 
OrthoClinicals-USA). The data of this study was recorded as protected health information (PHI) 
and analysed with version 20 of Statistical Package for the Social Sciences (SPSS).  
Results: The average serum magnesium level was lower significantly in the CVD patients 
(0.82±0.16) as compared to the control (0.87±0.07; p-value = 0.02); and magnesium 
abnormalities (both low and high) were positively associated with CVD cases resulting in an 
odds ratio (OR) of 5.42 (CI = 1.45 – 20.26; p-value = 0.01). Even though the trend of higher 
odds of outcome persisted when the exposed group was treated as those having only high 
magnesium levels, the odds ratio was not statistically significant (1.74 (0.19 – 21.38; p-value = 
0.54). With an adjusted OR from binary logistics of systolic blood pressure (SBP) increment of 
ii 
 
ten (10) and a body mass index (BMI) increment of five (5), magnesium categories (in terms of 
low, normal and high values) were found to be associated with inorganic phosphate categories, 
adjusted calcium, creatinine kinase (CK) categories, diastolic (DBP) categories, albumin (ALB) 
categories and total cholesterol (Tchol) categories. By this the study established that there was a 
positive association between serum magnesium level and other biochemical parameters 
measured (p = 0.01). The study parameters, thus, had strong evidence against the null hypothesis. 
Conclusion: The cardiovascular disease patients and controls in this study were adult with 
majority having secondary school education and of Christian religious background. The study 
established statistically that there was a significant positive association between mean serum 
magnesium levels in the controls and cases. Despite this significance, further statistical analysis 
in accounting for confounding variables with or without rules established that there was a 
significant relationship between serum magnesium levels in the studied cases and controls. The 
study established that serum magnesium level was also positively associated with other 
biochemical parameters measured. The study also established a 13.33% increase risk of CVD 
prevalence in the participants with low magnesium levels. The current study has further provided 
information on the relationship between the serum magnesium levels and other biochemical 
markers in the investigations in CVD subjects and how adjusted odds ratio with SBP increments 
of ten (10) and BMI increment of five (5) could make magnesium levels closely relate with 
potassium, phosphate, calcium, CK, DBP, albumin and total cholesterol. 
 
 
 
 
iii 
 
DEDICATION 
To God Almighty whose abundant grace has seen me through with this work, be the glory, 
great things he has done. This work is dedicated to my wife, Mercy Bonakor, for the 
tremendous sacrifices made and children; Semefa, Senyo, Seyram and Selikem 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
iv 
 
ACKNOWLEDGEMENT 
I thank God Almighty for taking me through this programme successfully and my wife, Mercy 
for the tremendous sacrifice smade and children; Semefa, Senyo, Seyram and Selikem for the 
patience and support throughout this study. 
 
I express my deepest gratitude goes to Dr. Seth Dortey Amanquah of the School of Biomedical 
and Allied Health Sciences, for his able supervision, encouragement, patience and guidance in 
the course of the study. 
 
I further wish to express my sincerest gratitude to Dr. Albert Akpalu of the Department of 
Medicine and Therapeutics and School of Medicine and Dentistry for his co-supervision, 
insightful contribution, support and encouragement. 
 
I am all time grateful to Dr. Grace Korkor Ababio of Biochemistry Department, Rev. Dr. Charles 
Antwi-Bosiako of Physiology Department, and Mr. Confidence Blinksen for their statistical 
analysis, constructive critiquing and contribution in making this work a reality. I also wish to 
acknowledge Prof. Nafiu Amidu and Rev. Dr. Thomas Ndanu for their guidance, counsel and 
tutelage in the result analysis and discussion.  
 
Finally I wish to thank Hospital Management for the opportunity, staffs of Central Laboratory 
Service, various Units of the Department of Medicine and Therapeutics, SME, volunteered 
subjects as well as friends and families who in diverse ways helped me produce this work. 
 
v 
 
TABLE OF CONTENTS 
Contents 
DECLARATION....................................................................................................................................... i 
ABSTRACT ............................................................................................................................................ ii 
DEDICATION ....................................................................................................................................... iv 
ACKNOWLEDGEMENT.......................................................................................................................... v 
TABLE OF CONTENTS .......................................................................................................................... vi 
LIST OF FIGURES ................................................................................................................................. ix 
LIST OF TABLES .................................................................................................................................... x 
LIST OF ABBREVIATIONS ..................................................................................................................... xi 
CHAPTER ONE ......................................................................................................................................... 1 
1.0 INTRODUCTION ............................................................................................................................. 1 
1.1      Background ............................................................................................................................... 1 
1.2  Problem Statement .................................................................................................................... 6 
1.3  Justification ................................................................................................................................ 6 
1.4  General Aim ................................................................................................................................ 7 
1.5  Specific Objectives ...................................................................................................................... 7 
CHAPTER TWO ........................................................................................................................................ 8 
2.0 LITERATURE REVIEW ...................................................................................................................... 8 
2.1 Cardiovascular Disease................................................................................................................ 8 
2.2 Pattern of CVD in Developed and Developing Countries .............................................................. 9 
2.3 Burden of Cardiovascular Disease in Sub-Saharan Africa ........................................................... 10 
2.4  Burden of Cardiovascular Disease in Ghana ............................................................................... 11 
2.5 Cardiovascular Health ............................................................................................................... 12 
2.6 Aetiology of Cardiovascular Disease .......................................................................................... 13 
2.7  Types of Cardiovascular Diseases (CVDs) ................................................................................... 16 
2.7.1   Ischaemic Heart Disease .......................................................................................................... 16 
2.7.2    Hypertensive Heart Disease (HHD) .......................................................................................... 17 
2.7.3    Stroke/Cerebroovascular Accident (CVA) ................................................................................ 18 
2.8  Serum Magnesium Levels in CVD.............................................................................................. 19 
2.9  Protective Roles of Magnesium in CVD ..................................................................................... 20 
vi 
 
2.10   Magnesium and Vascular Smooth Muscle Cells (VSMCs) ......................................................... 21 
2.11   Magnesium and the Vascular Endothelium.............................................................................. 24 
2.12   Magnesium and the Myocardium ............................................................................................ 26 
2.13   Risk Factors of Cardiovascular Disease..................................................................................... 27 
2.14   Body Mass Index (BMI) ............................................................................................................ 28 
2.15   Serum Magnesium .................................................................................................................. 29 
2.16   Magnesium Intake, Metabolism and Homeostasis ................................................................... 30 
2.17   Hypomagnesemia in CVD ........................................................................................................ 32 
2.18   Causes of Hypomagnesemia in CVD ......................................................................................... 32 
2.19   Hypermagnesaemia in CVD ..................................................................................................... 34 
2.20     Serum calcium, HDL, LDL, Cholesterol and fasting blood sugar, PO4 and CK in CVD .................. 34 
CHAPTER THREE .................................................................................................................................... 36 
3.0 MATERIALS AND METHOD ........................................................................................................... 36 
3.1 Study design .......................................................................................................................... 36 
3.2 Study site ............................................................................................................................... 36 
3.3 Study population ................................................................................................................... 36 
3.4 Inclusion criteria .................................................................................................................... 36 
3.5 Exclusion criteria.................................................................................................................... 37 
3.6 Sample size determination ..................................................................................................... 37 
3.7  Sampling Technique ............................................................................................................... 38 
3.8 Subject Recruitment .............................................................................................................. 39 
3.9         Demographics........................................................................................................................ 39 
3.10       Blood collection ..................................................................................................................... 39 
3.11 Laboratory Procedures .......................................................................................................... 40 
3.12 Data Analysis ......................................................................................................................... 47 
CHAPTER FOUR ..................................................................................................................................... 49 
4.0 RESULTS ....................................................................................................................................... 49 
4.1       Study Population Demographics and Characteristics ............................................................... 49 
4.2        A comparison of the clinical and biochemical variables between cases and controls of the  
study population ............................................................................................................................... 51 
4.3       Cross tabulation ...................................................................................................................... 52 
4.4       Mg2+ stratification of the study population ............................................................................. 53 
4.5       Association between Magnesium and biochemical variables in the study populations ............ 55 
vii 
 
4.6       Association between Magnesium abnormality and cardiovascular disease ............................. 55 
4.7       Adjusted Odds Ratio (OR) ....................................................................................................... 56 
4.8       Linear regression analysis ....................................................................................................... 57 
4.9       Univariate analysis .................................................................................................................. 58 
CHAPTER FIVE........................................................................................................................................ 59 
5.0 DISCUSSION AND CONCLUSION ................................................................................................... 59 
5.1 DISCUSSIONS ................................................................................................................................ 59 
5.1.1     Serum Magnesium levels and CVDs ........................................................................................ 59 
5.1.2     Association between Magnesium and biochemical variables in the study population ............. 60 
5.2CONCLUSIONS .............................................................................................................................. 64 
5.3 LIMITATIONS................................................................................................................................ 65 
5.4 RECOMMENDATIONS................................................................................................................... 65 
REFERENCES ...................................................................................................................................... 67 
APPENDIX I ............................................................................................................................................ 95 
PARTICIPANT CONSENT INFORMATION SHEET ................................................................................... 95 
APPENDIX II ........................................................................................................................................... 95 
INFORMED CONSENT FORM .............................................................................................................. 95 
APPENDIX III .......................................................................................................................................... 96 
QUESTIONNAIRE ................................................................................................................................ 96 
APPENDIX IV .......................................................................................................................................... 97 
DATA COLLECTION PROCEDURE ......................................................................................................... 97 
APPENDIX V ........................................................................................................................................... 98 
OTHER DATA COLLECTION PROTOCOL ............................................................................................... 98 
 
 
 
 
 
viii 
 
LIST OF FIGURES 
Figure 2:I  Vascular effects of magnesium sulphate ............................................................................... 23 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ix 
 
LIST OF TABLES 
Table 2:1  Stages of elevated Blood Pressure and Hypertension ................................................ 18 
Table 2:2 WHO Obesity Classification ...................................................................................... 28 
Table 4:1    Distribution of general characteristics and demographics of the study population ... 50 
Table 4:2    Comparison of clinical and biochemical variables between cases and controls of the 
study population ........................................................................................................................ 52 
Table 4:3     Cross Tabulation showing significant p-values ...................................................... 53 
2+
Table 4:4   Clinical variables stratified by Mg  categories ........................................................ 54 
Table 4:5 Association between Magnesium and biochemical variables in cases ......................... 55 
Table 4:6 Odds ratio showing Magnesium abnormality (both high and low levels) and 
cardiovascular disease ............................................................................................................... 55 
Table 4:7   Odds ratio showing the risk of having abnormal Mg (high) in the study population . 56 
Table 4:8  Adjusted odds ratio (binary logistics) ........................................................................ 57 
Table 4:9  Linear Regression ..................................................................................................... 57 
Table 4:10  Univariate Analysis ................................................................................................ 58 
 
 
 
 
 
 
x 
 
LIST OF ABBREVIATIONS 
AHA…………………………………………………………………America Heart Association 
ASA………………………………………………...……………….America Stroke Association 
Ca……………………………………………………………………Calcium 
2+
Ca ………………………………………………………………….Calcium Ion 
CCF……………………………………………...………….………Congestive Cardiac Failure 
CHD…………………………………………………………………Coronary Heart Disease 
CK…………………………….…………………………………..…Creatinine Kinase 
CVD…………………………………………………………………Cardio vascular Disease 
CVH……………………………………………..…………………..Cardiovascular Health 
FBG………………………………………………………………….Fasting Blood Glucose 
……………………………………………………………………………………………..…….  
HDL High Density Lipoprotein
HHD………………………………………….………………………Hypertensive Heart Disease 
HIV………………………………………….……………………….Humane Immune Virus 
IFG…………………………………………………………...……….Impaired Fasting Glucose 
IGT………………………………………………………………..…..Impaired Glucose Tolerance 
IHD…………………………………………………………………...Ischaemic Heart Disease 
+
K ……………………………………………………………………..Potassium Ion 
K………………………………………………………………………Potassium 
KBTH...................................................................................................Korle Bu Teaching Hospital 
LDL…………………………………………………………………..Low Density Lipoprotein 
Mg……………………………………………………………………Magnesium 
2+
Mg .....................................................................................................Magnesium Ion 
+
Na ……………………………………………………………………Sodium Ion 
xi 
 
Na……………………………………………………………………Sodium 
NCD………………………………………………………………...Non-Communicable Disease 
PO4.....................................................................................................Phosphate 
TG…………………………………………………..………………Triglyceride 
WHF………………………………………………………………..World Heart Foundation 
WHO……………………………………………………………….World Health Organisation 
WLE………………………………………………………………..World Life Expectancy 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
xii 
 
CHAPTER ONE 
1.0 INTRODUCTION 
1.1 Background 
Cardiovascular disease (CVD) refers to diseased conditions that entail the blood vessels 
including veins, arteries and capillaries or the heart, or both. In other words these are diseases 
that affect the cardiovascular system (World Health Organization, 2011). Cardiovascular disease 
includes among others congestive cardiac failure (CCF), hypertensive heart disease (HHD), 
ischemic heart disease (IHD) and stroke (World Health Organization, 2011).Cardiovascular 
disease as a major non-communicable disease (NCD) worldwide has been on the increase over 
time and this has become a burden. Cardiovascular disease is responsible for nearly 10% of all 
th
deaths globally at the commencement of the 20  century (Agyemang et al, 2012) and the 
percentage rose to approximately 30% by the start of the 21st century (Mbewu & Jean-Claude, 
2006). 
 
 For the past 6 decades among the high-income countries, cardiovascular disease was ranked the 
highest among the leading causes of death. However, it has now become the main cause of death 
in most countries described as having low and middle income in their gross domestic product 
(Mbewu & Jean-Claude, 2006). It is projected that about 80% of all deaths occurring globally as 
a result of cardiovascular diseases are taking place in such developing countries. The rise in 
deaths due to CVD, accompanied by the continual high death rate emanating from contagious 
diseases in these countries is referred to as the double disease burden by the experts (Mbewu & 
Jean-Claude, 2006; de-Graft, 2007). Cardiovascular disease is therefore one of the topmost two 
attributes of death following diarrheal diseases in Ghana (WHO, 2010). 
 
1 
 
Cardiovascular disease was reported as the primary cause of death in 1991 and 2001 in Ghana 
(Accra) and  it has since remain a leading cause of mortality in the country (Agyei-Mensah & de-
Graft Aikins, 2010; Agyemang, 2015). It is believed among a cross-section of people (indigenes) 
and some experts in Ghana that CVD is not common and therefore, did not pose any grievous 
public health difficulties (de-Graft Aikins, 2007). Furthermore, Ghana’s healthcare system is not 
equipped with the needed means to tackle the dual burden of non-communicable diseases and the 
commonplace acute communicable diseases (de-Graft Aikins, 2007).  Epidemiologic 
surveillance has been noticed to be crucial in assessing the quantum of ailment in the population 
so as to prevent this from escalating further (Gordis, 2009). It is established that population-
based data is more often appropriate for these types of observations as it reveals the magnitude of 
CVD in a particular country. However, this information is hard to come in a lot of developing 
countries and Ghana is no exception. There has been an institution of demographic and 
surveillance systems in 3 ecological areas in Ghana (Navrongo, Kintampo and Dodowa) to 
collect such data, however these opportunities provided have not been fully taken advantage of 
(Oduro et al., 2012). Hospital records have however become a way of monitoring CVD mortality 
in the absence of such data (Gordis, 2009). Notwithstanding the added input, biochemical 
markers have been implicated in CVD but data seem conflicting. It is expedient to know the 
characteristics of these biochemical parameters and investigate as such. 
 
The human body contains an abundant and ubiquitous amount of magnesium. It plays very 
crucial roles in cellular physiology as well as cellular and biochemical processes that regulate 
cardiovascular function. It also functions by controlling the tone of the vascular smooth muscle, 
myocardial excitability and functions of endothelial cells. This makes magnesium very essential 
to the pathogenesis of a lot of cardiovascular systems disorders such as coronary artery disease, 
2 
 
congestive heart failure, atherosclerosis, hypertension and cardiac arrhythmias. Previous studies 
have indicated that magnesium was very instrumental in the pathogenesis of cardiovascular 
diseases. Consumption of low magnesium was established to be linked to future possibility of the 
following diseases; hypertension (Witteman, Grobbee, Derkx, Bouillon, de Bruijn, & Hofman, 
1994), stroke (Larsson et al., 2012) and diabetes (Meyer et al., 2000). Metabolic syndrome was 
strongly and positively correlated with reduced serum magnesium concentrations (Rotter et al., 
2015). Low serum magnesium levels were additionally recounted as a predisposing factor for the 
commencement and progress of type 2 diabetes mellitus (Kao et al., 1999) and coronary heart 
disease (CHD) (Liao et al., 1998). Also, low serum magnesium is also linked to increased 
cardiovascular mortality in different groups (Adamopoulos et al., 2009; Sakaguchi et al., 2014). 
An appropriate magnesium administration averts intracellular reduction in the levels of 
magnesium, potassium and high energy phosphates thereby improving metabolism in the 
myocardium; preventing intramitochondrial calcium influx or buildup and decreasing 
susceptibility to free radicals derived from oxygen. Magnesium, therefore, can influence the tone 
of the vascular system, anti-aggregation of platelet and the cascading coagulation systems,the 
severity of cardiac arrhythmias, the size of infarct scar, endothelial function, lipid metabolism, 
myocardial infarction and cardiovascular failure (Shechter & Shechter, 2013). 
 
The other protective effects of magnesium in CVD include coronary and systemic vasodilation, 
enhanced angiogenesis, improved exercise duration and cardiac performance, inhibition of 
reperfusion injury, catecholamine inhibition, and mild reduction of blood pressure and reduced 
systemic vascular resistance (Shechter & Shechter, 2013). However, a study by Khan et al. 
(2013) concluded their proposition of low serum magnesium concentration being a veritable 
predisposition factor for one to develop high blood pressure or cardiovascular disease (Khan, 
3 
 
Lubitz, Sullivan, Sun, Levy, & Vasan, 2013).Low serum potassium is established to be a strong 
and objective predictor of death in congestive cardiac failure (Salah et al., 2015). The 
concentrations of magnesium and potassium in both plasma and muscle are decreased in 
congestive cardiac failure (Macdonald & Struthers, 2004). Therefore, a patient that responded to 
treatment showed a significant rise in concentration of intracellular potassium (Macdonald & 
Struthers, 2004). 
 
According to reports from other studies conducted it was indicated that serum calcium may 
interfere with the composition of lipid fractions such as total triacylglycerol, low density 
lipoprotein (LDL) and level of high density lipoprotein (HDL) in CVDs (Reid et al., 2002). Due 
to the fact that a disordered lipid is a key predisposition for coronary heart disease (CHD), the 
association between the levels of serum calcium and CHD needs extensive study. The correlation 
of serum calcium with total serum cholesterol has also been established by other studies (Gallo et 
al., 2016) and with levels of one’s blood glucose (Saltevo et al., 2011) and as a result obviously 
linked with the pathogenesis of metabolic syndrome. Some studies reported that middle-aged 
men with high serum calcium have an independent, prospective predisposition for myocardial 
infarction (Gallo et al., 2016). It is reported in other studies that people with type 2 diabetes 
mellitus have an increased chance of developing CVD including IHD (Deedwania & Fonseca, 
2005; Mazzone et al., 2008). 
 
It is also reported that clogging of the vascular system by atherosclerotic plaque (atherosclerosis) 
usually predates the onset of clinical diabetes mellitus (Hu et al., 2002). Also, evidences from 
experimental studies have proved that there is an association between impaired glucose tolerance 
(IGT) and increased morbidity and death of cardiovascular diseases (Nathan et al., 2007). 
4 
 
Despite this relationship observed between impaired fasting blood glucose (IFG) and the possible 
predisposition to having CVD and IHD, there is still no certainty to the association (Liu et al., 
2007,   Levitzky et al., 2008). 
 
There is a reported significantly high serum Creatine kinase (CK) levels in CVD patients as 
compared to the controls (Al-Hadi & Fox, 2009). Therefore, it is anticipated that stroke-related 
myocardial injury is as a result of high CK levels which served as a biological indicator. It has 
further been indicated that certain people suffering from ischaemic stroke, subarachnoid 
hemorrhage, and head trauma have an elevated creatine kinase activity in the nonexistence of 
any clinically evident acute coronary syndrome (Peppes et al., 2008; Manea et al., 2015). 
 
In populations with high chronic kidney diseases, phosphate (PO4) levels are consistently known 
to be linked with cardiac calcification, CVD, and death (Foley et al., 2009). High phosphataemia 
is a key predisposing factor for cardiovascular situations, calcification of vascular system and 
cause of death among clients with or without kidney disease (Kendrick et al., 2011). The 
established processes by which elevation in the level of phosphate result in undesirable outcomes 
are not yet completely understood as serum phosphate levels within the referenced laboratory 
range are even correlated with a higher threat of cardiovascular events and death. However, 
existing scientific evidence suggests that there is a direct action of phosphate on calcification of 
the vascular systems and modulation by such major hormones as calcitriol and fibroblast growth 
factor-23 (Kendrick et al., 2011). 
 
In spite of the convincing epidemiologic associations between biochemical parameters like 
phosphate excess and cardiovascular disease, not much studies has been conducted to establish 
5 
 
this relationship to confirm or otherwise the risks and benefits of treatment. It is anticipated that 
some biochemical variables like the levels of serum phosphates can cover the traditional 
reference range and result in condition of CVD. Investigating biochemical markers e.g. PO4 
levels, in the CVDs may be important since many clinical mediations may be appropriate for the 
primary or secondary avoidance of CVDs. 
 
1.2  Problem Statement 
In both the advanced and developing countries, cardiovascular disease is on the increase 
although the disease burden and mortality may be different (WHO, 2005).  A recent study done 
in Ghana also reported increasing burden and mortality of cardiovascular disease (Sanuade et al., 
2013). Studies have suggested some relationship between cardiovascular health and magnesium 
(Shechter & Shechter, 2013); however very little information on the specific association between 
cardiovascular disease and serum magnesium levels is currently available in Ghana. Available 
literature reveals that most of these works were done in advanced countries and some evidence 
that there is increasing cardiovascular disease burden in Ghana. However, there are no available 
data on the specific relationship between magnesium and cardiovascular diseases (CVD) in 
Ghana to the best of my knowledge.  
 
1.3  Justification 
Cardiovascular disease (CVD) being a debilitating disease with devastating financial 
consequences, clients may benefit from early magnesium supplementation to ameliorate the 
severity of relevant CVD conditions. Data generated may offer policy makers and other health 
professionals the opportunity to build on the derived baseline knowledge to provide further 
6 
 
solutions. Laboratory request for magnesium is generally low among the requesting physicians in 
KBTH in spite of the reported benefits that can be available to the affected clients/patients.  
 
1.4  General Aim 
To determine serum magnesium levels and related biochemical parameters in cardiovascular 
disease attending Korle-Bu Teaching Hospital and compare with apparently healthy subjects.  
 
1.5  Specific Objectives 
The specific objectives were to: 
1. Determine the demographic status of subjects 
2. Determine serum magnesium levels in cardiovascular disease. 
3. Determine serum levels of biochemical parameters in cardiovascular disease 
4. Determine the relationship between serum magnesium levels and other biochemical 
parameters in the studied subjects. 
5. Determine the likely risk of magnesium level in developing cardiovascular disease. 
 
 
 
 
 
 
 
 
7 
 
CHAPTER TWO 
2.0 LITERATURE REVIEW 
2.1 Cardiovascular Disease 
Cardiovascular disease (CVD) is defined by the American Heart Association (AHA) as diseases 
of the heart and its blood vessels as well as the vascular diseases of the brain (Kasner & Sacco, 
2013). Cardiovascular diseases are accountable for more than 17.3 million deaths annually and 
for 31% of all deaths in the world accounting for the number one cause of death (WHO, 2008). 
This condition is the prominent non-communicable disease with almost 50% of the estimated 36 
million deaths due to non-communicable diseases being as a result of CVDs. Approximately 
10% of the worldwide burden of disease is ascribed to CVD. An important predisposing 
comorbidity of heart and respiratory disease, stroke, diabetes and cancer include the tobacco 
smoking, harmful alcohol use, lack of physical exercise and consumption of unhealthy diet 
(Mendis et al., 2011). 
 
Cardiovascular diseases are also defined as a collection of debilitating disarray of the heart and 
its associated blood vessels with destructive complications in individuals who have been 
affected. This has become the primary basis of non-communicable disease worldwide and 
comprise of: cerebrovascular disease (stroke) which essentially alters the vessels that supply 
blood to the brain; coronary heart disease which affects the vessels that supply blood to the heart 
muscles; rheumatic heart disease which comes about as a result of damage to the heart muscle 
and heart valves from rheumatic fever and peripheral artery disease caused by streptococcal 
bacterial infection which affects the vessels supplying blood to the arms and legs. It also includes 
congenital heart disease which is as a result of distortion of structures of the heart present at 
birth, deep vein thrombosis and pulmonary embolism resulting from blood clots in the veins of 
8 
 
the leg, which can dislodge and translocate to the heart and lungs (WHO, 2007). Heart attacks 
and strokes are generally acute events and are primarily caused by an obstruction that prevents 
blood from flowing to the heart or brain. This is as a result of an accumulation of fatty deposits 
on the internal walls of the blood vessels. Stroke attacks are usually caused by bleeding from a 
blood vessel in the brain or by blood clots (WHO, 2007). 
 
2.2 Pattern of CVD in Developed and Developing Countries 
Ironically, the burden of CVD-related morbidity and mortality has rather been increasing 
although the sub-Saharan Africa region is considered to consist largely of the youngest human 
populations internationally. Between 1990 and 2013, Moran et al. (2014) reported in their study 
that CVD-related deaths were the highest in that region as compared to other parts of the world 
that remained steady or declined. According to Livesay (2007), CVD-related deaths were the 
most important cause of death among the populations that aged above 45 years and thereby 
accounted for nearly 9.2% of all deaths occurring in the African region in 2001. It was further 
reported that about 7-10% of all adult admitted with medical conditions to health facilities in 
Africa were as a result of CVDs with heart failure alone representing approximately 3-7% 
(Mocumbi, 2012). It was reported that cerebrovascular accident (CVA) generally known as 
Stroke death rates are similar to that of the developed countries although Africa has the least 
coronary artery disease (CAD) death rates (WHF, 2015). In 2010, Stroke was ascribed as the 
main cause of CVD mortality and death in Africa. In that singular year, stroke accounted for 
approximately half a million deaths which represented 4.4% of all deaths in Sub-Saharan Africa 
(Ofori-Asenso & Garcia, 2016). The main acquired CVD in children and adolescents in Africa is 
rheumatic heart disease. The prevalence of this category of CVD is the highest in the world 
accounting for about 15-20 per 1,000 population (WHO, 2005). On the whole, more than half of 
9 
 
the CVD-related deaths in Africa happen between the ages of 30-69 years in many people. This 
is a decade or more lower than comparable group in the advanced world (Agyemang, 2015). It is 
projected that the burden of CVD will keep rising in Africa and by the year 2020 will become 
doubled the burden in 1990 (Mbewu & Mbany, 2015). Globalization has partly been attributed 
for the increasing burden of CVDs and its related diseases or its predisposition on the African 
continent. 
 
2.3 Burden of Cardiovascular Disease in Sub-Saharan Africa 
Cardiovascular disease is the first of the top 10 causes of death in Africa and complications such 
as stroke and renal disease are becoming progressively more common. Modifiable predisposing 
factors like obesity, hypertension, tobacco use, physical inactivity and raised cholesterol levels 
are known key drivers of the disease (Abanilla et al., 2011). Evidence has it that countries within 
Sub-Saharan African region are presently undergoing a swift epidemiological transitions typified 
by an increase in altering traditional lifestyle characteristics afforded by globalization and 
urbanization (BeLue et al., 2009). It was estimated in 2005 that about 17.5 million people 
perished from CVD. This represented about 30% of all worldwide deaths for which 
approximately 80% emanated from developing countries with sub-Saharan Africa inclusive 
(WHO, 2007). The Sub-Saharan Africa consists of regions within Africa that are completely or 
partly located south of the Sahara Desert with Ghana, Nigeria and South Africa inclusive. These 
countries are presently experiencing a raised incidence of NCDs, especially CVD due to rapid 
epidemiological transitions with increased urbanization (Kadiri & Salako, 1997) and changing 
lifestyle factors (BeLue et al., 2009).  South Africa’s CVD related death is reported to be the 
second major cause of death after HIV representing 40% of deaths among adults (Peer et al., 
2008).  
10 
 
 
Several other literature reviews also show that the incidence of cardiovascular disease (CVD) has 
risen considerably to become the primary cause of morbidity and mortality in the sub-Saharan 
Africa (Addo et al., 2007; Vendathan & Fuster, 2008 & BeLue et al., 2009). Cardiovascular 
disease (CVD) as a main element of non-communicable diseases is costly in terms of 
management and interferes with socioeconomic activities. This will continue to exhaust already 
scarce health resources in the Sub-Saharan African region. The increase in economic situation 
has worsened the poverty gap. Also with the perennial health-care worker shortages across the 
region, the response to this escalating CVD burden has seriously been hindered and this can pose 
a new public health challenge in the region. (Kadiri, 2005; Seedat, 2007 & BeLue, 2009). For 
this reason cost-effective ways to detect, control and prevent CVD are immediately required. 
 
2.4  Burden of Cardiovascular Disease in Ghana 
In Ghana, CVD remains the principal cause of death within the last two decades (de-Graft 
Aikins, 2007). The socioeconomic challenge of CVDs is on a steady increase in Ghana for which 
globalization is undoubtedly reported to be contributing to in no small ways by driving 
significant behavioural changes across the country (Ofori-Asenso & Garcia, 2016). The WHO 
has also identified CVDs as the leading cause of death among the non-communicable diseases in 
Ghana (WHO, 2011) and only second after infectious diseases including diarrheal illnesses 
(WHO, 2010).  
 
 A study conducted within a 5year period between January 2006 and December 2010 at Korle Bu 
Teaching Hospital (KBTH) of Ghana revealed that cardiovascular deaths diagnosed at autopsy 
during this period accounted for about 22.5% of all deaths (Sanuade et al., 2014). This figure is 
11 
 
closely collaborated by World Life Expectancy publication of 17.59% (32,922) of all deaths 
attributable to CVD accounted for by stroke, coronary heart disease (CHD) and hypertension. 
According to published WHO data in 2014, coronary heart disease deaths in Ghana accounted 
for about 6.48% of total deaths registered. The age adjusted death rate was 96.73 per 100,000 
population and making Ghana ranks number 75 in the world (WLE, 2016).  
 
Non-communicable diseases (NCDs) in Ghana accounted for an estimated 39 per cent of all 
mortality in 2008 and in the same year, the most prevalent NCDs were cardiovascular diseases 
accounting for 18% of all diseases reported (Commonwealth Health, 2016). Review of many 
literature available show that cerebrovascular accidents (stroke) constitute a significant source of 
CVD morbidity and mortality in Ghana. In a two-year study by Agyemang et al. (2012) on the 
incidence of stroke in the Ashanti region of Ghana, it was  reported that stroke alone, of the CVD 
burden in Ghana constituted 9.1% of total admission of all medical adults and 13.2% of all 
medical adult deaths within that period. In an older but similar cross-sectional study of fatal 
stroke cases over a 5-year period by Wiredu & Nyame (2001) in persons aged 20 years and 
above and confirmed at autopsy in Korle Bu Teaching Hospital, mortality from stroke 
constituted 11% within the 5-year period of 1994 to 1998. Compared with the last study done in 
1981 on the same parameters, stroke still remains an important cause of CVD deaths in Accra, 
Ghana. 
 
2.5 Cardiovascular Health 
The ultimate cardiovascular health is defined by American Heart Association as the presence of 
both ideal health behaviors and ideal health factors. Ideal health behaviors are characterized by 
the avoidance of smoking, good physical activity, healthy diet and a body mass index below 25 
12 
 
2
kg/m . Ideal health factors are characterized by fasting plasma glucose concentration below 
5.6mmol/L, untreated blood pressure below 120/80 mmHg and (untreated total cholesterol below 
5.2mmo/L (Lloyd-Jones et al., 2010). 
 
In this study, cardiovascular health (CVH) is defined as the absence of cardiovascular disease or 
absence of disease of the heart and its blood vessels as defined above. The perfect cardiovascular 
health is characterized by good health behaviours such as non-smoking habit, good body mass 
index, adequate physical exercise, healthy diets, and acceptable referenced levels of total 
cholesterol, fasting blood glucose and normal range of blood pressure. Conversely, these metrics 
also serve as good CVD risk factors. These ideal cardiovascular health metrics were goals set by 
American Heart Association (AHA) to enhance the cardiovascular health of Americans by 20% 
by 2020 (Folsom et al., 2011). 
 
2.6 Aetiology of Cardiovascular Disease 
Recent advances in experimental and epidemiological research have proven the crucial role 
2+
magnesium ions (Mg ) play in the origin and cause of cardiovascular pathologies. 
Hypomagnesemia in human subjects is frequently linked to an imbalance of electrolytes such as 
+ + 2+
sodium (Na ), potassium (K ) and calcium (Ca ). Different kinds of heart diseases, for example, 
ischemic heart disease, sudden cardiac death, atheroscelerosis, congestive heart failure, cardiac 
arrhythmias and ventricular complications as seen in diabetes mellitus come about as a result of 
2+ +
unusual dietary insufficiency of Mg  coupled with defects in the metabolism of Mg2 . 
Magnesium deficiency leads to advanced vasoconstriction of the coronary vessels resulting in a 
drop in oxygen and nutrient transfer to the cardiac myocytes (Chakraboti et al., 2002) 
 
13 
 
Balance in body electrolytes has been considered a key factor necessary to maintain 
cardiovascular stability especially congestive heart failure (CHF). Amongst the shared 
electrolytes, the importance of magnesium has been a subject of debate due to problems 
associated with accurate and precise measurement and other related factors such as aberrations in 
other electrolytes. The serum magnesium concentration characterizes less than 1% of total body 
stores and is not reflective of total-body magnesium concentration. Magnesium is a significant 
cofactor in numerous enzymatic activities in the body and contributes to steady cardiovascular 
haemodynamics and electrophysiologic functioning. Its deficiency is common and is usually 
linked to risk factors and heart failure complications (Douban et al., 1996). 
 
Epidemiological studies conducted in several nations including the USA, Finland, South Africa, 
Canada, England, France, Germany and Netherlands have shown, for example, that drinking 
water with low magnesium content is linked to the incidence and death from coronary artery 
disease (Seelig & Rosanoff, 2003; Shechter & Shechter, 2013).The highest risk for coronary 
artery disease (CAD) has been associated with subjects with low serum magnesium 
concentration (Liao et al., 1998). The National Health and Nutrition Examination Survey 
(NHANES) epidemiologic study established an inverse association of serum magnesium and 
death from CAD and all-cause mortality (Ford, 1999). Eating food that has low magnesium 
content was found to escalate the incidence of CAD by 2.1% in comparison to high magnesium 
content (Abbott et al., 2003). Low serum magnesium levels were linked to a threefold incidence 
of cerebrovascular accident (CVA) in peripheral artery disease patients compared to those with 
high levels of magnesium concentrations (Amighi et al., 2004). 
 
14 
 
An inverse association exists between food magnesium content and the incidence of metabolic 
syndrome (He et al., 2006). Prospective epidemiologic studies have described various 
relationships between magnesium and the risk of CVD (Qu et al., 2013; Abbott et al., 2003). 
Commonly, a stronger correlation existed for serum rather than dietary magnesium. The 
relationship between serum magnesium and risk of CAD seem to be stronger for fatal events 
rather than non-fatal ones, which can possibly be explained if magnesium has a protecting role 
against fatal ventricular arrhythmias and thus sudden cardiac death (SCD) (Ford, 1999). This 
theory was further buttressed by ecologic studies, which reported an inverse relationship between 
regional drinking water hardness and sudden cardiac death (Chiuve et al., 2011) and autopsy and 
many prospective studies have shown that lower myocardial magnesium levels were found in 
SCD victims as compared with death from trauma (Abbott et al., 2003). However, researchers 
from the Netherlands found no evidence for an overall significant association between tap water 
hardness, magnesium or calcium concentrations, and IHD mortality or stroke mortality (Leurs et 
al., 2010). 
 
The magnesium content of foods in the USA has dropped over the last 20 years and the 
incidence of CAD is also on the rise (Shechter & Shechter, 2013).It has been put forward that the 
effect of magnesium in preventing CVD may be attributed to a decline in inflammatory response. 
Arise in extracellular magnesium levels leads to phagocyte and endothelial cell activation 
(Shechter & Shechter, 2013). Inflammation caused by experimental magnesium deficiency is the 
mechanism that induces high plasma triglyceride levels and proatherogenic changes in 
lipoprotein profile. In magnesium deficiency states, endothelial cells are known to actively lead 
to inflammation. There is an existing inverse relationship between intake of magnesium and 
markers of systemic inflammation and endothelial dysfunction in healthy persons (Song et al., 
15 
 
2007). Animal models of magnesium deficiency have been proven to induce a clinical 
manifestation of inflammatory syndrome characterized by leukocyte and macrophage activation, 
inflammatory cytokines release and acute phase proteins as well as extreme free radicals 
production (Pachikian et al., 2010; Lin et al., 2010). Several mechanisms may act cumulatively 
and or synergistically to protect myocytes and that establishes the basis for supplementation with 
magnesium in patients with heart disease (Shechter & Shechter, 2013). This is in agreement with 
many other studies (Seelig & Rosanoff, 2003; Shechter & Shechter, 2005; Agarwal, 2016). 
 
2.7  Types of Cardiovascular Diseases (CVDs) 
2.7.1 Ischaemic Heart Disease 
Ischaemic heart disease (IHD) has various alternative names. They include coronary artery 
disease (CAD) or coronary heart disease (CHD). It is a condition that affects the supply of blood 
to the heart. It is a group of heart diseases that include myocardial infarction (MI),stable angina, 
unstable angina and sudden cardiac death (SCD) (Wong, 2010). Within the cardiovascular 
diseases, IHD is the most common kind (Moran et al., 2014). The coronary arteries supply 
oxygenated blood to the heart muscles and no alternative blood supply exists. Therefore, a 
thinning or blockage in the coronary arteries known as atherosclerosis reduces the supply of 
blood to the heart and its muscles resulting in ischemia of the muscles causing angina pectoris. 
The risk factors of the condition include high blood pressure, lack of exercise, smoking, obesity, 
hyperlipaedemia, diabetes, excessive alcohol intake, and poor diet among others (Mendis et al., 
2011 and Mehta et al., 2014). 
 
As a result of limitation of oxygenated blood flow to the heart and its muscles due to 
atherosclerotic plague formed from calcium phosphate deposition with cholesterol in the arteries, 
16 
 
the condition of ischaemia results. This is myocardial cell starvation secondary to oxygen 
deprivation resulting myocardial infarction (MI) commonly known as heart attack. This leads to 
damage, scarring and death of the heart muscles. Myocardial damage and scarring may cause 
failure of heart muscle regrowth. Chronic high grade stenosis of the coronary arteries may induce 
transient ischaemia which may also lead to the initiation of a ventricular arrhythmia. The 
resultant ventricular arrhythmia may end in ventricular fibrillation leading to death (Ambrose & 
Singh, 2015). 
 
2.7.2 Hypertensive Heart Disease (HHD) 
Hypertensive heart disease (HHD) refers to complications of heart conditions caused by high 
blood pressure (Badii, 2017). While there are a number of definitions of hypertensive heart 
disease in the medical literature, according to Alegría-Ezquerra et al, 2006), the term is very 
commonly utilised in the classification of diseases. In 2013 hypertensive heart disease resulted in 
1.07 million deaths as compared with 630,000 deaths in 1990 (GBD, 2013). According to the 
medical dictionary, MedicineNet (2016), Heart failure (HF) as a major outcome of hypertensive 
heart disease is often referred to as congestive heart failure (CHF) and this is as a result of 
theheart’s inability to pump blood proficiently and adequately to sustain flow to meet the body's 
requirements. Heart failure is as a result of damaging or over loading of the heart muscle thereby 
minimizing its effectiveness. Conditions that can cause this disease include myocardial infarction 
(in which the heart muscle does not get sufficient oxygen and dies), hypertension (which 
increases the force of contraction needed to pump blood) among others.  
 
 
 
 
17 
 
Table 0:1Stages of elevated Blood Pressure and Hypertension 
Category Systolic BP (mmHg)             Diastolic BP (mmHg) 
Optimal  < 120            < 80 
Prehypertension 120-139              80-89 
Stage I  140-159              90-99 
Stage II  >160            >100 
Source: Chobanian et al., 2003 
 
2.7.3 Stroke/Cerebrovascular Accident (CVA) 
A stroke sometimes called a cerebrovascular accident (CVA) is one of the most common medical 
emergencies related to the heart. This occurs when blood is deprived from reaching an important 
area like the brain resulting in the death of the brain cells due to lack of oxygen and glucose 
needed to survive. MedicineNet (2016) defines Cerebrovascular accident as the sudden death of 
some brain cells as a result of the absence or insufficient oxygen flow when the flow of blood to 
the brain is impaired by blockage or rupture of an artery to the brain.  
 
However, the American Heart Association (AHA) and American Stroke Association (ASA) 
updated definition of stroke for the 21st century defined Stroke as an episode of neurological 
dysfunction caused by focal cerebral, spinal or retinal infarction. It further described central 
nervous system infarction as brain, spinal cord or retinal cell death due to ischaemia based on 
either pathological, imaging or other objective evidence of cerebral, spinal cord or retinal focal 
ischaemic injury in a defined vascular distribution; or clinical evidence of cerebral, spinal cord or 
retinal focal ischaemic injury based on symptoms persisting for at least 24-hours or until death, 
and other aetiologies excluded (Kasner & Sacco, 2013). 
18 
 
 
There are two types of stroke; ischaemic and haemorrhagic strokes. The ischaemic strokes is as a 
result of clots accumulating in the blood vessels of the brain, in blood vessels leading to the brain 
(thrombotic strokes), or blood clots or other substances such as bone marrow fats released by 
means ofa fracture, bacterial clumps as in endocarditis and air particle in blood vessels elsewhere 
in the body and then get transported to the brain (embolic stroke). These clots from any of the 
various sources can block the blood flow to the cells of the brain thus causing ischaemic damage 
and death to the brain cells via oxygen and glucose deprivation. Haemorrhagic strokes 
commonly due to high blood pressure and brain aneurysm occur when there is a burst of blood 
vessel in the brain leading to blood draining into the brain tissue and causing destruction to the 
cells of the brain (Gund et al., 2006). 
 
2.8 Serum Magnesium Levels in CVD 
Being an active mineral biologically, magnesium is commonly found in such foods as unpolished 
grains, green leafy vegetables and nuts. In most western countries the consumption of 
magnesium is reported to be inadequate as a lot their food eaten is processed. (Ford & Mokdad, 
2003; Song & Liu, 2012). Low dietary intake, high consumption of processed foods and certain 
diseased conditions usually account for hypomagnesemia (Swaminathan, 2003). Hypertension 
and other cardiovascular diseases as well as nerve disorders have been treated using magnesium 
for years (Gums, 2004; Houston & Harper, 2008).The levels of magnesium in the body are 
closely regulated by the parathyroid hormone. Excess magnesium levels are gotten rid of through 
faecal excretion and urinary system (Smith, 2009). Majority of the stock of magnesium in the 
body are bound and unavailable while only close to 1% are available in the blood since serum 
levels are tightly regulated through uptake, then renal and fecal excretion. To this end, about 310 
19 
 
to 350 mg of magnesium has been recommended for daily consumption. Elemental magnesium 
supplementation for adult male and female has been capped at 350 mg per day. As a supplement, 
magnesium is generally reported to be a safe. There are virtually no recorded incidences of 
excessive dietary magnesium to be the cause of any adverse effect. However, wanton 
consumption of supplemental magnesium may lead to stomach cramps and incidence of diarrhea 
(NIH, 2005). In the same report, the National Institutes of Health reported that the signs of 
excess magnesium more than five times the daily recommended dose may cause signs and 
symptoms as those of magnesium deficiency. These signs and symptoms may include mental 
confusion and instability, nauseating feelings, losing appetite, having diarrhea, breathing 
difficulties, muscle weakness (NIH, 2005).  
 
In an ARIC Study in four US communities involving 15,248 subjects, men and women aged 
between 45 and 64 of both blacks and whites, Ma et al., (1995) concluded that 
hypomagnesaemia and low dietary intake of magnesium may have contributed to the etiologies 
of CVD including development of atherosclerosis, hypertension and diabetes. In their study, both 
serum and dietary magnesium levels were lower in blacks than whites. The average serum 
magnesium levels were significantly lower in the cases with CVDs compared to the controls that 
had no any CVD conditions.  
 
2.9 Protective Roles of Magnesium in CVD 
Exogenous magnesium administration helps maintain intracellular magnesium, potassium and 
high energy phosphates levels. This helps to improve the metabolism of the myocardium; and 
prevent the influx of calcium intramitochondrially. It also avoids the unintended accumulation of 
oxygen-derived free radicals as well as reduces their cellular vulnerability. Magnesium in 
20 
 
summary, therefore, have a positive effect on the tone of the vasculature, prevent aggregation of 
platelet, improves the functioning of the coagulation system and endothelium, limit the size of 
infarct scar, enhance lipid metabolism, prevents cardiac arrhythmias and myocardial infarction as 
well as reduces cardiovascular failure (Shechter & Shechter, 2013). The other protective effects 
of magnesium in CVD include coronary and systemic vasodilation, enhanced angiogenesis, 
improved exercise duration and cardiac performance. Also includes inhibition of reperfusion 
injury, catecholamine inhibition, mild reduction of blood pressure and reduced systemic vascular 
resistance (Shechter & Shechter, 2013). In contrast, a study by Khan et al., (2010) indicated that 
their data derived from a huge, community-based cohort failed to agree with the assumption of 
serum hypomagnesium being a predisposition variable in the development of cardiovascular 
disease including hypertension. 
 
2.10 Magnesium and Vascular Smooth Muscle Cells (VSMCs) 
Hardening of the vasculature as a result of excessive calcium deposition is commonly present in 
such conditions as atherosclerosis, aneurysms, diabetes, hypertension, and chronic kidney 
disease (CKD). This observation is found related to elevated predisposition to cardiovascular 
morbidity and mortality. (Kaye et al., 2007). Hypercalcaemia add to the elevated hardness of the 
vasculature, contributes to its reduced elasticity and decreased distensibility and this is a 
characteristic feature of the vascular phenotype in hypertension (Dao et al., 2005; Kanemaru et 
al., 2008). Hardening of the vasculature as a result of excessive calcium deposition is a firmly 
regulated course similar to processes involved in the formation of bone (Peacock, 2010).  Factors 
enhancing excessive deposition of calcium in the vascular system include disorders in the 
metabolism of relevant minerals, particularly in the conditions of hyperphosphatemia and high 
serum calcium level (Peacock, 2010).   
21 
 
 
In hypomagnesaemia, vascular calcification may be exacerbated, (Montezano et al., 2010) and 
studies have indicated a direct relationship between hyperphosphatemia, hypercalcaemia, and 
calcification of the arteries. Results obtained from in vitro observations support this reported 
relationship. It can be explained that when vascular smooth muscle cells are exposed to high 
concentrations of phosphate and calcium a dose-dependent elevation in mineralization was 
noted. This indication is associated with vascular smooth muscle cells differentiation to an 
osteoblastic phenotype (Speer et al., 2009). This process is facilitated by upregulating 
transcription factors like core-binding factor 1/Runx2, MSX-2 and bone morphogenetic protein-
2. These factors are involved in the regular process of bone development. They therefore, control 
the expression of osteogenic proteins. These osteogenic proteins include osteonectin, alkaline 
phosphatase, osteocalcin, bone sialoprotein and collagen-1 (Freedman et al., 2009). Magnesium 
inhibits vascular calcification by reducing the expression of osteocalcin and bone morphogenetic 
protein-2 and related activities. This leads to elevated production of calcification inhibitors such 
as osteopontin and matrix Gla protein (Montezano et al., 2010). These bone-forming 
transcription factors and proteins can be produced by vascular smooth muscle cells in a culture 
medium. The effect of vascular calcification was seen increased with high concentrations of 
calcium, phosphorous, glucose, cytokines, oxidized lipids in the presence of a low concentration 
of magnesium (Speer et al., 2009).Conversely, an alternative process involved in creating a 
condition of vascular mineralization is through the absence of inhibitors to vascular calcification. 
They include matrix Gla protein, fetuin-A, osteopontin and pyrophosphate (Scatena et al., 2007; 
Zarjou et al., 2009). 
 
 
22 
 
Figure 0: IVascular effects of magnesium sulphate 
 
Source: (Euser and Cipolla, 2009). 
 
Magnesium is an important vasodilator of arteries. Magnesium in the vascular smooth muscle 
usuallycompetes with calcium for the available binding sites. Decreased calcium channel activity 
is associated with reduced mobilization of intracellular calcium. This results in the relaxation and 
vasodilatation of the vasculature. Magnesium further promotes high expression of prostaglandin 
I2 in the endothelium. This action tend storeduce the aggregation of platelet. Magnesium also 
23 
 
promotes the elevation of nitric oxide production resulting in vasodilatation of the vascular 
system (Euser & Cipolla, 2009). 
 
2.11  Magnesium and the Vascular Endothelium 
The functional patency of the wall of the vasculature is known for the maintenance of the cells of 
the endothelium. The integrity of the vascular wall is critically important to ensure that vessel 
permeability is properly controlled and non-agglutination of blood–tissue interface is maintained. 
Vascular wall patency is also needed for modulation of blood flow and its vascular resistance. 
Functional integrity of the vascular endothelium further assures proper regulation of the immune 
and inflammatory reactions (Cines et al., 1998). Endothelial dysfunction has been established to 
play a major role in a variety of diseases including: diabetes and thrombosis (Cines et al., 1998); 
atherosclerosis and hypertension (Lifton et al., 2001). Research supports the hypothesis of 
endothelial dysfunction as the common connection between risk factors and burden from 
atherosclerosis (Ross, 1999). The dysfunction of the endothelium has been found to play a role in 
the following: increasing chemokine secretion and cell permeability to lipids; the process of 
lesion formation by promoting leukocyte adherence; improving LDL oxidation, migration and 
platelet activation and stimulating vascular smooth muscle cell proliferation (Ross, 1999). Also, 
cells of the endothelium play a role in angiogenesis (the branching and sprouting of capillaries 
from pre-existing blood vessels), which is a firmly controlled event critical in development, 
reproduction and healing of wound (Folkman, 1995). Endothelial cells are freely exposed to 
numerous signals (metabolites, cytokines, ions, free radicals, shear stress) due to their strategic 
position at the boundary between blood and vessels, some of which may stimulate maladaptative 
changes in function.  
 
24 
 
Experimental evidence shows that low magnesium status is vital to the pathogenesis of 
cardiovascular diseases (Seeling & Rasandof, 2003). Hypomagnesaemia which is common in 
western countries is a common denominator in coronary artery disease (Liao et al., 1998), 
hypertension (Peacock et al., 1999), thrombosis (Mussoni et al., 2001) and diabetes (Barbagallo 
et al., 2007).  Oral magnesium therapy to patients suffering from coronary artery disease  has 
been linked to improvement of their endothelial function (Shechter et al., 2000) accompanied by 
a drop in plasma levels of very low density lipoprotein (VLDL), triglycerides, and apo-B (Geiger 
& Wanner, 2012).  Hyperlipaemia, early atherosclerotic lesions and inflammation have been 
seen with experimental magnesium deficiency (Rayssiguier et al., 2001). Fortification of 
drinking water with magnesium led to the inhibition of atherogenesis in APO-E-deficient mice 
fed on a high cholesterol diet (Ravn et al., 2001). A deficiency in magnesium has been proven to 
lessen tumour growth through mechanisms that are not clear (Wolf & Cittadini, 1999). Also 
magnesium facilitates wound healing as high levels of magnesium has been identified in early 
wound fluid, once movement of cells into the wound is started (Grzesiak & Pierschbacher, 
1995). Research based evidence suggests that extracellular magnesium concentrations play an 
important role in controlling activities of the endothelium (Zhang et al., 1993). Deficiency in 
magnesium also promotes free radical-induced cytotoxicity in the cells of the endothelium 
(Montezano et al., 2010). Again many biological processes at the cellular and molecular levels 
have been shown to be impacted by magnesium deficiency. The mechanisms are systemic 
reactions such as inflammation and endothelial dysfunction, as well as changes at the cellular 
level, such as mitochondrial dysfunction and excessive fatty acid production (Zheltova et al., 
2016). 
 
25 
 
2.12 Magnesium and the Myocardium 
Intravenously administered magnesium has been used in the treatment and prevention of several 
acute cardiovascular diseases (Fawcett et al., 1999). Magnesium functions as a cardiovascular 
drug together with calcium but possess antagonistic and antiadrenergic properties (James, 1992). 
The cardiovascular properties of magnesium include its antiarrhythmic effect, direct and indirect 
dilatation of blood vessels, and possibly myocardial depression. Although there is a direct 
correlation between plasma magnesium concentration and cardiovascular effects at near steady 
state, the association between the time courses of magnesium concentration and its effect is 
poorly understood (Nakaigawa et al., 1997). Higher knowledge of this association may account 
for the design of acute intravenous dose regimens of magnesium for the management of 
cardiovascular symptoms. It is however uncertain whether the cardiovascular effects of 
magnesium are facilitated by its intracellular or extracellular concentration or a combination of 
both (Qu et al., 2013). Magnesium also has effect on some cardiovascular parameters such as 
myocardial blood flow and myocardial contractility. 
 
Deficiency in magnesium has been linked to the following: enhanced platelet aggregation; 
induction of severe vascular damage in the heart; increase in blood pressure; enhanced 
development of atherosclerosis; and vasoconstriction of the coronary arteries (Geiger & Wanner, 
2012). A reduced magnesium concentration appears to be complicated in the pathogenesis of 
ischaemic heart disease by changing lipoprotein composition, thus making individuals prone to 
atherosclerosis (Montezano et al., 2010). It was reported that, a reduction in infarct size occurred 
when magnesium was administered to animal models with myocardial infarction (Antman, 
1996). According to an autopsy studies done on patients who had died from ischaemic heart 
disease, it was revealed that there were lower magnesium levels in their myocardium and muscle 
26 
 
in comparison to patients who had died from non-cardiac causes (Gund et al., 2006). Overall 
intracellular magnesium declines while free ionized intracellular magnesium increases during 
myocardial ischaemia (Manea et al., 2015). In addition, ischaemia leads to intracellular calcium 
overload and it is hypothesised that administration of magnesium reduces calcium overload for 
the reason that there was evidence that these two elements are in competition with each another 
for the same binding sites. Magnesium may be seen as a natural ‘calcium antagonist’ (Mentezano 
et al., 2010) and can attenuate phosphate-induced apoptosis in vascular smooth muscle cells 
(Kircelli et al., 2012). 
2.13 Risk Factors of Cardiovascular Disease 
According to WHO (2007), one of the greatest challenges that faces health systems worldwide is 
the increasing burden of chronic diseases. Cardiovascular diseases are one the common non-
communicable chronic disease conditions increasingly affecting the human population. A 
chronic condition according to WHO is defined as needing and ongoing management over a 
period of years or decades (Nolte & Mckee, 2008). Cardiovascular risk factors are elements that 
predispose or increase the chances of developing cardiovascular disease. These factors are 
generally grouped into two categories, namely, modifiable and non-modifiable risk factors.  
With the modifiable risk factors, the individual is able to control the elements; these are 
preventable risk factors afforded by appropriate lifestyles. The non-modifiable risk factors are 
genetic or inherited elements outside the control of the individual and are therefore, non-
preventable in the development of cardiovascular diseases (WHF, 2016) 
 
 
 
27 
 
2.14 Body Mass Index (BMI) 
The body mass index (BMI) or Quetelet index is an assessment calculated from the mass(weight) 
and height of an individual. It is defined as the weight of an individual divided by the square of 
2
the height of the person, and this is generally expressed in units of kg/m . The National Institutes 
of Health (NIH) continue to utilise BMI as a standard tool for measuring normal weight, 
overweight and obesity. These classifications serve as an acceptable clinical tool for assessing 
whether people who are inactive in their daily routines are underweight, overweight or obese 
with a variety of exceptions including the infirm, elderly, children, and athletes. It is primarily 
utilised as a way of correlating comparative groups related by their general weight. It remains an 
important means of estimating adiposity although not very accurate in its measurements. The 
tool of BMI has also remained in use by WHO as an acceptable standard for measuring obesity 
statistics for nearly four decades now. 
Table 0:2 WHO Obesity Classification 
2
Category BMI (kg/m ) 
from To 
 
Very severely underweight 15.0 
 
Severely underweight 15 16 
Underweight 16 18.5 
Normal (healthy weight) 18.5 25 
Overweight 25 30 
Obese Class I (Moderately obese) 30 35 
Obese Class II (Severely obese) 35 40 
Obese Class III (Very severely obese) 40 
 
Source: WHO, 2006  
 
28 
 
These reference ranges are premised on the association between body weight, susceptible disease 
and death (WHO, 1995). The consequences of elevated level in adults means that those 
individuals picked as overweight and obese are at elevated risk for diseases such as hypertension, 
dyslipidaemia, coronary heart disease, stroke, type 2 diabetes mellitus, osteoarthritis among 
many others (NHLBI, 1998). 
 
2.15  Serum Magnesium 
Magnesium is an electrolyte which is often disregarded but is vital to life. Its use is seen in many 
enzymatic reactions. Magnesium is recognised to be key in the following processes: energy 
metabolism, utilization of glucose, protein synthesis, synthesis and breakdown of fatty acid and 
almost all hormonal reactions. As a result of its association with sodium, potassium, and calcium, 
it is also involved in the maintenance of ionic balance in the cells (Gums, 2004). It is a natural 
mineral found in diets that are rich in nuts, unpolished grains, and green vegetables (Song and 
Liu, 2012). Magnesium consumption is well-known to be insufficient in westernized populations 
(Ford & Mokdad, 2003; Shechter & Shechter, 2013). 
 
2+
Serum magnesium ion (Mg ) is considered the second most abundant intracellular cation and 
2+ + + 2+
the fourth most common cation in the body (Ca > K > Na > Mg ) (Laurant & Touyz, 2000). 
2+
Almost 65% of the total Mg  concentration in the body is found in bone, about 34% found in 
the muscle, however 1% is found in the extracellular fluid (Drueke and Lacour, 2007). 
2+
Magnesium ion (Mg ), be it intra and extracellular exists in 3 main states: (i) free or ionized 
(this is the physiologically active form); (ii) protein bound (this form bound to mostly cellular 
proteins and physiologically inactive); and (iii) form complexed to such anions like phosphate, 
citrate, bicarbonate and lactate). Of all the magnesium present in the extracellular fluid, 7% is 
29 
 
complexed to anions, 33% is protein bound and the remaining 60% exists in the physiologically 
ionized state (mostly bound to and transported by albumin) (Speich et al.,1981). Intracellular 
2+
magnesium (Mg ) is found in the compartments of the following cell organelles:mitochondria, 
nuclei, and endo/sarcoplasmic reticulum (Romani et al., 1993). In the nucleus and mitochodrion, 
magnesium binds to nucleic acid and chromatin, intermembrane proteins and matrix adenine 
phosphonucleotides respectively whilst it binds to ribonuclear proteins and phospholipids in the 
endo/sarcoplasmic reticulum (Romani, 2007). As a result of this bindingonly a minute fraction of 
intracellular magnesium occurs freely. The overall intracellular magnesium concentration spans 
4
between 14 and 20 x 10 mmol/l, while the intracellular free magnesium concentration is 
6
projected to be about 0.5–0.7 x 10 mmol/l (Romani et al., 1993; Wolf et al., 2003). 
 
2.16  Magnesium Intake, Metabolism and Homeostasis 
The blood level of magnesium is reliant on consumption of food and drinks rich in magnesium. 
The essential sources of dietary magnesium include green vegetables, legumes, whole seeds, 
unmilled grains and nuts. Fish, meat, and fruits have been known to also contain a good amount 
of magnesium. Hard water is another source of magnesium. Magnesium absorption is affected by 
several factors which either inhibit or enhance it. The presence of fibre, phytate, alcohol or 
excess amounts of phosphate and calcium can impede absorption of magnesium. Magnesium is 
usually lost from foods that undergo refining or processing (Saris et al., 2000; Shils & Shike; 
2006). There is an uncertain effect of vitamin D on magnesium absorption. However, vitamin D 
and its active metabolites have been demonstrated to cause a rise in magnesium absorption in the 
intestines in normal humans and patients that have failure of the kidney (Shils & Shike; 2006). 
Reference limit of plasma concentration of serum magnesium lies within the range (0.75 to 0.95) 
mM (Weisinger & Bellorin-Font, 1998). Recommended daily consumption of magnesium in diet 
30 
 
is 350 mg and 280mg for males and females respectively. Nonetheless, during pregnancy, the 
daily requirement is increased to 355 mg. Research has revealed the consumption of magnesium 
in countries in the West to be currently lower than the value recommended (Saris et al., 2000). 
 
Homeostasis of magnesium is reliant on the collective activities of the intestine, responsible for 
2+ 2+ 
Mg uptake from food, the bone, responsible for storing Mg in its hydroxy-apatite form, and 
2+ 
the kidneys, which regulates urinary Mg excretion. The maintenance of plasma magnesium 
levels is dependent on its consumption, effectiveness of absorption by the intestines and renal 
system and also on renal excretion including several other pertinent factors including hormone in 
circulation. Two pathways, paracellular and transcellular pathways result in the absorption of 
2+ 2+ 
Mg . Paracellular pathway is an inactive mechanism which leads to the absorption of Mg
through tiny spaces between epithelial. The transcellular pathway consists of the movement of 
2+ 
Mg through the interior of epithelial cell to the blood. A maximum of about 40% of magnesium 
in the diet is absorbed via the intestine at the ileum and jejunum. The absorption of magnesium 
begins after 1 hour to 8 hours of ingestion and the ingested material reaches the large bowel in 
humans after 12 hours where there is no absorption or absorption is minimal (Shils & Shike, 
2006; de Baaij et al. 2012).  
 
By the processes of glomerular filtration and tubular reabsorption, the kidneys play a crucial role 
in regulating magnesium homeostasis. About 10 % (approx 100 mmol or 2400mg) of the total 
body magnesium undergoes glomerular filtration in healthy human and only 5% is lost in urine 
with the remaining being reabsorbed in different sections of nephron. Sites for the reabsorption 
of magnesium include the proximal tubule, distal convoluted tubule and the thick ascending loop 
of Henle (de Baaij et al. 2012).   
31 
 
 
2.17 Hypomagnesemia in CVD 
The concentration of total magnesium present in our body may vary. Hypomagnesaemia shows 
reduction of body magnesium and it occurs when the serum magnesium concentration is less 
than 0.74mmol/l. Majority of hypomagnesaemia disorders come without any clear symptoms. 
Symptoms only occur when serum magnesium levels drops lower than 1.2mg/dl (Assadi, 2010). 
The overall prevalence of hypomagnesaemia is projected at 2% (Liamis et al., 2013). However it 
is thought to be as high as 53% in individuals within high-risk category which includes people 
suffering from chronic heart failure (Adamopoulos et al., 2009). Serum magnesium is still not 
measured frequently even though hypomagnesaemia may possibly have acute and chronic 
complications (de Baaij et al., 2015). 
 
Insufficiency in magnesium may be due to several causes and mechanisms which include: 
magnesium redistribution in the body; a drop in dietary intake as well as reduced absorption; 
diabetes mellitus; endocrine causes; renal loss; alcohol and drugs (Fawcett et al., 1999; 
Swaminathan, 2003). Hypomagnesaemia has been shown to be related to ventricular and atrial 
arrhythmias hence low serum magnesium could possibly be a risk factor for sudden cardiac death 
(Adamopoulos et al., 2009). 
 
2.18 Causes of Hypomagnesemia in CVD 
Magnesium redistribution: During certain conditions such as refeeding syndrome, magnesium 
moves from the extracellular fluid (ECF) to cells and bones of the body thus resulting in 
hypomagnesia. This redistribution of magnesium also occurs as a mechanism for correcting 
32 
 
acidosis. It is also seen in hungry bone syndrome, where patients have diffuse osteoblastic 
metastases (Swaminathan, 2003).  
Gastrointestinal causes: During certain conditions such as malabsorption syndrome and chronic 
diarrhea, intestinal absorption of magnesium might be impaired resulting in reduced levels of 
serum magnesium (Swaminathan, 2003).  
Renal loss: Loss of magnesium in urine might occur as a result of impairment in renal tubular 
reabsorption of magnesium. Excessive excretion of magnesium as seen in the use of diuretics 
may serve as an alternative cause of magnesium exhaustion from the loop of Henle being the key 
location for reabsorption of magnesium (Shils & Shike; 2006). Since tubular reabsorption of 
magnesium is related to sodium and calcium reabsorption, a fall in the reabsorption of sodium 
might result in magnesium loss (Weisenger & Bellorin-Font, 1998; Swaminathan, 2003).  A 
number of disorders have been implicated in the reabsorption of magnesium by the kidneys and 
include the barters (Swaminathan, 2003).   
Diabetes Mellitus: Diabetes is the most predominant disorder due to body magnesium 
insufficiency. Hyperglycosuria as seen in diabetes mellitus is known to cause loss of magnesium 
by the kidneys and osmotic diuresis which results in magnesium concentration lessening in the 
diabetes patient. Depletion in magnesium is known to disturb the secretion of insulin and result 
in insulin resistance. This observation may be as a result of unusual metabolism of blood glucose 
as magnesium is involved in the cycle. The action of tyrosine kinase at the insulin receptor may 
also be affected (Takaya et al., 2004). Low blood level of magnesium is also linked to mortality 
due to type 2 diabetes mellitus (Dasgupta et al., 2012). 
Alcohol intake: Hypomagnesaemia is implicated in prolonged alcoholism and has an incidence 
rate of 29.8%. This may be linked to poor nutritional intake by alcoholics, vomiting, and 
diarrhea. Chronic pancreatitis due to alcoholism with malabsorption may also cause 
33 
 
hypomagnesaemia. Other causes of hypomagnesaemia in alcoholics include deficiency in 
vitamin D, dysfunction of the renal tubules, and the alteration in ionic permeability by ethanol 
(Stasiukyniene, 2002; Romani 2008). Hypomagnesaemia may result in a number of disorders 
like cardiovascular disease, diabetes, and osteoporosis. Predominant indicator of 
hypomagnesaemia is hypocalcaemia, cardiac arrhythmias, and elevated blood pressure 
(Swaminathan, 2003). 
 
2.19 Hypermagnesaemia in CVD 
This is the presence of high amounts of magnesium in body and may be associated with 
excessive consumption of magnesium containing diet or drugs containing magnesium that is 
frequently observed in people having kidney failure or impaired kidney function. Manifestation 
of hypermagnesaemia is very uncommon. However it could lead to several cardiovascular, 
neuromuscular defects and hypocalcaemia. Symptoms of hypermagnesaemia include nausea, 
2+
headaches, vomiting, lethargy, and/or flushing.WhenMg  levels rise above 3.0mM, severe 
cardiac defects like hypotension and brachycardia occur. Extreme hypermagnesaemia can 
therefore result in cardiac arrest, then coma and death. However, hypermagnesaemia is unusual 
and until now has no genetic linkage. A markedly high body magnesium level may possibly lead 
to cardiotoxicity (Swaminathan, 2003). Strong clinical predictor for hypermagnesaemia is 
chronic kidney disease and patients on dialysis usually have raised magnesium concentration 
(Spiegel, 2011). 
2.20 Serum calcium, HDL, LDL, Cholesterol and fasting blood sugar, PO4 and CK in CVD 
The level of HDL cholesterol may be influenced by serum calcium. Serum calcium has also been 
shown to decrease the level of serum LDL and total cholesterol (Reid et al., 2002). Given that 
34 
 
dyslipidaemia is a principal predisposing factor for CHD, the association between calcium level 
of the body and CHD needs extensive study. Serum calcium has further been observed to rise 
with elevating levels of diastolic and systolic blood pressure (Kesteloot & Geboers, 1982); (Lind 
et al., 1988). Also, in people having excessive level of parathyroid hormone in circulation and 
hence suffer from chronic hypercalcemia, hypertension is observed to be prevalent (Rosenthal & 
Roy, 1972) so that an elevated risk of mortality particularly from CVDs exists (Palmer et al., 
1987).  
 
Serum calcium has also correlates with serum cholesterol and blood glucose and is therefore 
clearly related with the metabolic syndrome (Lind et al., 1988).Some studies indicated that there 
was a significant positive correlation between triglyceride levels and serum calcium in the group 
with normal blood pressure and that LDL cholesterol showed a negative relationship with serum 
calcium in males but not in females (Vaskonen et al., 2002). Sex and racial differences are 
believed to influence the relationship between serum calcium and blood lipids. It is believed that 
consumption of diets with high calcium content might be correlated with less global adiposity 
(Torres et al., 2011).  
 
 
 
 
 
35 
 
CHAPTER THREE 
3.0 MATERIALS AND METHOD 
3.1 Study design 
This was a case-control study design with a convenience and randomised sampling technique 
conducted at the Department of Medicine and Therapeutics of the Korle Bu Teaching Hospital. 
 
3.2 Study site 
The sites include the Central Out-Patients Department (COPD), the Stroke unit and the Medical 
ward all under the Department of Medicine and Therapeutics   of the Korle Bu Teaching 
Hospital. The Department of Medicine and Therapeutics attends to a broad range of health 
conditions including patients of cardiovascular diseases for both in- and out-patient settings. It 
has a unit dedicated to Stroke patients and a day for conducting outpatient clinic for patients with 
CVD conditions with adequate medical experts. 
 
3.3 Study population 
The cases were recruited from those on admission in the Medical wards and the stroke unit while 
the control subjects were recruited from the Central Out-Patients Department of the Hospital and 
members of staff of the Hospital. Both cases and controls were age and gender matched. 
3.4 Inclusion criteria 
Cases: The cases included all adult male or female patients aged between 18 and 80 years 
clinically diagnosed by a physician of having CVD condition such as congestive cardiac failure 
(CCF), Ischaemic heart disease (IHD), hypertensive heart disease (HHD) and Stroke also known 
as cerebrovascular accident (CVA).  
36 
 
 
Controls: Other adult patients aged between 18 and 80 years reporting at the OPD of the KBTH 
with medical conditions other than CVDs. No record of hypertension, myocardial infarction or 
stroke, dyslipidaemia, diabetes, liver, kidney diseases or metabolic syndromes certified by the 
physician on duty. 
3.5 Exclusion criteria 
Any subject that failed to meet the inclusion criteria above was excluded from participating in 
the study. Any participant unwilling to sign the consent form was excluded from participating in 
the study. 
3.6 Sample size determination 
The study adopted Kelsey’s formula, (Kelsey et al., 1996), to calculate the sample size. In a 
similar work done in Indian population by Dasgupta et al., (2012), the prevalence rate of 
hypomagnesaemia found among the case group was 11.9% and among control group was 9.8%. 
However, this study presumed a prevalence rate of 28.9% in the case group and 8.9% in control 
group. A ‘’ratio’’ (r) of 1:1 is being kept between the control group and case group for the study. 
The study also maintains an 80% ‘’statistical power’’ (Zβ) with 95% ‘’confidence level ’’ (Zα) 
and an ‘’Odds Ratio’’ (OR) of 2.74.  
 
 
 
 
 
 
37 
 
Thus;  
Two-sided confidence level (1-alpha) (Zα) 95 1.96 
Power(% chance of detecting) (Zβ) 80 0.84 
Ratio of Controls to Cases        (r) 1:1 1 
Hypothetical proportion of controls with exposure (P2)  8.9% 0.089 
Hypothetical proportion of cases with exposure (P1) 28.9% 0.289 
P (0.089+0.289)/2 0.189 
Least extreme Odds Ratio to be detected (OR) 2.74 2.74 
 
r 1 ( p)(1 p)(Z  Z )
2
/2
With the formula n  ( )
r (p1  p2 )
2
 
2
n1= (1+1) (0.189) (1-0.189) (0.84+1.96)  
2
         1   (0.289-0.089)  
2
n1= (2)     (0.189) (0.811) (2.8)  
2
       1            (0.2)  
2
n1= (2) (0.189) (0.811) (2.8)  / 0.04 
n1= (2) (1.202) / 0.04 
n1= 60 
Since the study keeps 1:1 controls ratio, then the n1=n2. Thus, N= n1+n2 = 120.  
3.7  Sampling Technique 
A convenience and systematic sampling technique was employed in this study.  
38 
 
3.8 Subject Recruitment 
Designed questionnaires were administered to gather basic demographic and CVD risk factor 
data of participants. Selected nurses and Laboratory Scientists were trained for the administration 
and collection of data and samples.  
 
Upon case identification and referral by the physician, the investigator systematically approached 
the prospective participant and provided education on the importance of the research as 
contained in participant information sheet and sought their consent. However, in very ill but 
potential participants, this education and consent was directed at the close relative care-taker. 
Where consent was obtained, the questionnaire was administered and samples collected in 
accordance with study protocol. . 
3.9        Demographics 
The weight, sex, height, age and occupation of all the participants were obtained through the 
administration of questionnaires. The questionnaire for patient baseline demographics and 
clinical information was pretested with participants (10 cases and 10 controls) at the Department 
of Medicine and Therapeutics of the KBTH. 
3.10        Blood collection 
The method as described in the Standard Operating Procedure for performing venepuncture in 
the KBTH by Acquaye (1991) was used. Venous fasting blood samples were collected from the 
patients into labeled tubes (sodium fluoride and gel separator tubes).  Rubber tourniquet was tied 
to the biceps about 8cm above the elbow joint for less than one minute and the site of puncture 
cleansed with methylated spirit. Then 5ml of blood was drawn from the brachial vein with a 19G 
hypodermic needle fixed on 5mls syringe.  All aseptic conditions were adhered to.  The blood 
39 
 
was immediately divided into two tubes; gel separated (4.0ml) for the general chemistry and 
sodium fluoride (1.0ml) for blood glucose measurement.  The blood in the sodium fluoride tube 
was mixed to prevent clotting by gently inverting the tubes four times manually. Each tube was 
appropriately labeled with codes, sample type and time taken. The blood in the sodium fluoride 
tube was spun at a speed of 2000 RPM for 5 minutes while the blood in the gel separating tubes 
were allowed to clot before spinning at a speed of 3000 RPM for 10 minutes.   
Each sample plasma and serum were drawn from the test tube with a micropipette into two 
0
labeled eppendorf tubes and stored at -20 Cuntil required for use. 
 
3.11 Laboratory Procedures 
2+ 2+ +
Serum Mg , Ca , K , PO4, CK, Total Cholesterol and Fasting Plasma Glucose. 
 Laboratory processing of the samples collected was carried out at the Central Laboratory Service 
of the Korle Bu Teaching Hospital using Dry Chemistry Analyzer VITRIOS 5.1 FS by 
OrthoClinicals-USA to run the following.  
 2+ 2+ + Mg , Ca , K , PO4, CK, total cholesterol and fasting plasma glucose. 
 
2+
3.11.1 Principle of the Procedure for VITROS Magnesium (Mg ) Slide test 
The principle involves a colorimetric approach with approximate incubation time of 5 minutes at 
a 37 °C temperature environment using heparinised plasma or serum in a reaction volume of 5 
μL in which a drop of patient sample is deposited on the slide and is evenly distributed by the 
spreading layer to the underlying layers. Magnesium (both free and protein-bound) from the 
sample then reacts with the formazan dye derivative in the reagent layer; the high magnesium 
affinity of the dye dissociates magnesium from binding proteins. The resulting magnesium-dye 
complex causes a shift in the dye absorption maximum. The amount of dye complex formed is 
40 
 
proportional to the magnesium concentration present in the sample and is measured by reflection 
density at 630nm wavelength on VITROS 5,1 FS Chemistry Analyzer. 
Reaction Scheme  
2+ 2+ 2+ 2+
Mg  + Ca  chelator Mg  + Ca -chelator complex  
2+ 2+
Mg  + formazan dye derivative pH 9.75 Mg -dye complex 
  
2+
3.11.2 Principle of the Procedure for VITROS Calcium (Ca ) Slide test 
The principle involves a colorimetric approach with approximate incubation time of 5 minutes at 
a 37 °C temperature environment using heparinised plasma or serum in a reaction volume of 10 
μL. A drop of patient sample is deposited on the slide and is evenly distributed by the spreading 
layer to the underlying layers. The bound calcium is dissociated from binding proteins, allowing 
the calcium to penetrate through the spreading layer into the underlying reagent layer. There, the 
calcium forms a complex with Arsenazo III dye, causing a shift in the absorption maximum. 
After incubation, the reflection density of the coloured complex is measured 
spectrophotometrically at 680nm wavelength on VITROS 5,1 FS Chemistry Analyzer. The 
amount of colored complex formed is proportional to the calcium concentration in the sample. 
Reaction Scheme  
2+
Ca  + Arsenazo III   pH 5.6      colored complex 
 
3.11.3 Principle of the Procedure for VITROS Phosphate (PO4) Slide test  
The principle involves a colorimetric method using heparinised plasma or serum in which a drop 
is placed on a multilayered, analytical element coated on a polyester support. The analytical 
principle is based on the reaction of inorganic phosphate with ammonium molybdate to form an 
ammonium phosphomolybdate complex at acidic pH, as described by Fiske and Subbarow 
41 
 
(1925). p-Methylaminophenol sulfate, an organic reductant reported by Gomori (1942), reduces 
the complex to form a stable heteropolymolybdenum blue chromophore. A drop of patient 
sample is deposited on the slide and is evenly distributed by the spreading layer to the underlying 
layers. Phosphorus in the specimen forms a complex with ammonium molybdate. This complex 
is reduced by p methylaminophenol sulfate to give a blue complex. The concentration of 
phosphorus in the sample is determined by measuring the heteropolymolybdenum blue complex 
by reflectance spectrophotometry on VITROS 5,1 FS Chemistry Analyzer. 
Reaction Scheme 
Inorganic phosphate + ammonium molybdate  pH 4.2  ammonium phosphomolybdate complex  
ammonium molybdate complex   p-methylaminophenol      sulphate heteropolymolybdate blue  
 
3.11.4 Principle of the Procedure for VITROS Creatine Kinase (CK) Slide test 
The principle of the method is based on an enzymatic multilayered rate approach with 
approximate incubation time of 5 minutes at a 37 °C temperature environment using heparinised 
plasma or serum. A drop of patient sample is deposited on the slide and is evenly distributed by 
the spreading layer to the underlying layers. This layer also contains N-acetylcysteine (NAC) to 
activate CK without pretreating the sample. When the sample is deposited on the slide, creatine 
kinase catalyzes the conversion of creatine phosphate and ADP to creatine and ATP. In the 
presence of glycerol kinase (GK), glycerol is phosphorylated to L-α-glycerophosphate by ATP. 
Oxidation of L-α-glycerophosphate to dihydroxyacetone phosphate and hydrogen peroxide 
occurs in the presence of L‑α‑glycerophosphate oxidase (α-GPO). Finally, leuco dye is oxidized 
by hydrogen peroxide in the presence of peroxidase to form a dye. Reflection densities are 
monitored during incubation. The rate of change in reflection density is then converted to 
enzyme activity measured at 670nm wavelength on VITROS 5,1 FS Chemistry Analyzer. 
42 
 
Reaction Scheme 
2+
creatine phosphate + ADP      CK,  NAC, Mg        creatine + ATP 
glycerol + ATP       GK     L-α-glycerophosphate + ADP 
L-α-glycerophosphate + O2       α-GPO      dihydroxyacetone phosphate + H2O2 
H2O2 + leuco dye           peroxidase       dye + 2H2O 
 
3.11.5 Principle of the Procedure for VITROS Albumin (ALB) Slide test 
The principle of the method is a colorimetric based approach with approximate incubation time 
of 2.5 minutes at a 37 °C temperature environment using heparinised plasma or serum in a 
reaction volume of 5.5 μL. A drop of patient sample is deposited on the slide and is evenly 
distributed by the spreading layer to the underlying layers. When the fluid penetrates the reagent 
layer, the bromcresol green (BCG) dye diffuses to the spreading layer and binds to albumin from 
the sample. This binding results in a shift in wavelength of the reflectance maximum of the free 
dye. The color complex that forms is measured by reflectance spectrophotometry measured at 
630nm wavelength on VITROS 5,1 FS Chemistry Analyzer. The amount of albumin-bound dye 
is proportional to the concentration of albumin in the sample. 
Reaction Scheme 
albumin + bromcresol green (BCG)                            BCG-albumin complex 
 
+
3.11.6 Principle of the Procedure for VITROS Potassium (K ) Slide test 
This method uses a potentiometric principled approach with approximate incubation time of 2 
minutes at a 37 °C temperature environment using heparinised plasma or serum in a reaction and 
reference volumes of 10 μL. This is a multilayered, analytical element coated on a polyester 
support that uses direct potentiometry for measurement of ionic potassium on VITROS 5,1 FS 
43 
 
Chemistry Analyzer. The slide consists of two ion-selective electrodes, each containing 
valinomycin (an ionophore for potassium), a reference layer, and a silver chloride layer coated 
on a polyester support. A drop of patient sample and a drop of VITROS Reference Fluid on 
separate halves of the slide results in migration of both fluids toward the center of the paper 
bridge. A stable liquid junction is formed connecting the reference electrode to the sample 
indicator electrode. Each electrode produces an electrical potential in response to the activity of 
potassium applied to it. The potential difference poised between the two electrodes is 
proportional to the potassium concentration in the sample. 
 
3.11.7 Principle of the Procedure for Fasting Blood Glucose (GLU) Slide test 
The method is a colorimetric approach based principle with approximate incubation time of 5 
minutes at a 37 °C temperature environment using heparinised plasma or serum in a reaction 
volume of 10 μL. A drop of patient sample is deposited on the slide and is evenly distributed by 
the spreading layer to the underlying layers. The oxidation of sample glucose is catalyzed by 
glucose oxidase to form hydrogen peroxide and gluconate. This reaction is followed by an 
oxidative coupling catalyzed by peroxidase in the presence of dye precursors to produce a dye. 
The intensity of the dye is measured by reflected light measured at 540nm wavelength on 
VITROS 5,1 FS Chemistry Analyzer. The dye system used is closely related to that first reported 
by Trinder (1969). The chemistry of the glucose slides has been described by Curme and Rand 
(1997). 
Reaction Scheme 
β-D-glucose + O2 + H2O     glucose oxidase      D-gluconic acid + H2O2 
2H2O2 + 4-aminoantipyrine + 1,7-dihydroxynaphthalene       peroxidase        red dye 
 
44 
 
3.11.8 Principle of the Procedure for VITROS Cholesterol (CHOL) Slide test 
The principle of the method involves a colorimetric approach with approximate incubation time 
of 5 minutes at a 37 °C temperature environment using heparinised plasma or serum in a reaction 
volume of 5.5 μL and measured at 540nm wavelength. The method is based on an enzymatic 
method similar to that proposed by Allain et al. (1974). A drop of patient sample is deposited on 
the slide and is evenly distributed by the spreading layer to the underlying layers. The Triton X-
100 (TX100) surfactant in the spreading layer aids in dissociating the cholesterol and cholesterol 
esters from lipoprotein complexes present in the sample. Hydrolysis of the cholesterol esters to 
cholesterol is catalyzed by cholesterol ester hydrolase. Free cholesterol is then oxidized in the 
presence of cholesterol oxidase to form cholestenone and hydrogen peroxide. Finally, hydrogen 
peroxide oxidizes a leuco dye in the presence of peroxidase to generate a colored dye. The 
density of dye formed is proportional to the cholesterol concentration present in the sample and 
is measured by reflectance spectrophotometry on VITROS 5,1 FS Chemistry Analyzer. 
Reaction Scheme  
Lipoprotein        TX100       cholesterol + cholesterol esters + proteins  
Cholesterol esters + H2O    cholesterol ester hydrolase       Cholesterol + fatty acids  
Cholesterol + O2     cholesterol oxidase       cholest-4-en-3-one + H2O2  
H2O2 + leuco dye      peroxidase           dye + 2H2O 
 
3.11.9 Principle of the Procedure for VITROS Triglycerides (TRG) Slide test 
The principle of the method is a colorimetric approach with approximate incubation time of 5 
minutes at a 37 °C temperature environment using heparinised plasma or serum in a reaction 
volume of 5.5 μL and measured at 540nm wavelength. The analysis is based on an enzymatic 
method as described by Spayd et al. (1978). A drop of patient sample is deposited on the slide 
45 
 
and is evenly distributed by the spreading layer to the underlying layers. The Triton X-100 
surfactant in the spreading layer aids in dissociating the triglycerides from lipoprotein complexes 
present in the sample. The triglyceride molecules are then hydrolyzed by lipase to yield glycerol 
and fatty acids. Glycerol diffuses to the reagent layer, where it is phosphorylated by glycerol 
kinase in the presence of adenosine triphosphate (ATP). In the presence of L-α-glycerol- 
phosphate oxidase, L-α-glycerophosphate is then oxidized to dihydroxyacetone phosphate and 
hydrogen peroxide. The final reaction involves the oxidation of a leuco dye by hydrogen 
peroxide, catalyzed by peroxidase, to produce a dye. The density of the dye formed is 
proportional to the triglyceride concentration present in the sample and is measured by 
reflectance spectrophotometry on VITROS 5,1 FS Chemistry Analyzer. 
Reaction Scheme  
Lipoproteins    surfactant    triglycerides + proteins  
Triglycerides + H2O     lipase     glycerol + fatty acids  
Glycerol + ATP      glycerol kinase + MgCl2      L-α-glycerophosphate + ADP  
L-α-glycerophosphate + O2  L-α-glycerol-phosphate oxidase  dihydroxyacetone phosphate + 
H2O2 + leuco dye      peroxidase     dye + 2H2O 
 
3.11.10 Principle of the Procedure for VITROS High Density Lipoprotein (HDL) Slide test 
The method uses a colorimetric approach with approximate incubation time of 5 minutes at a 37 
°C temperature environment using heparinised plasma or serum in a reaction volume of 10 μL 
and measured at 670nm wavelength. The method is based on a non-HDL precipitation method 
similar to one used by Burstein et al. (1970) followed by an enzymatic detection similar to that 
proposed by Allain et al. (1974). A drop of patient sample is deposited on the slide and is evenly 
distributed by the spreading layer to the underlying layers. HDL is separated by the precipitation 
46 
 
of non- High Density Lipoproteins (non-HDL) using phosphotungstic acid (PTA) and 
magnesium chloride (MgCl2) in the spreading layer. The Emulgen B-66 surfactant in the 
spreading layer aids in the selective dissociation of the cholesterol and cholesterol esters from the 
HDL lipoprotein complexes present in the sample. Hydrolysis of the HDL-derived cholesterol 
ester to cholesterol is catalyzed by a selective cholesterol ester hydrolase. Free cholesterol is then 
oxidized in the presence of cholesterol oxidase to form cholestenone and hydrogen peroxide. 
Finally, hydrogen peroxide oxidizes a leuco dye in the presence of peroxidase to generate a 
colored dye. The density of dye formed is proportional to the HDL cholesterol concentration 
present in the sample and is measured by reflectance spectrophotometry on VITROS 5,1 FS 
Chemistry Analyzer. 
Reaction Scheme  
HDL + non-HDL     PTA/MgCl2         high density lipoproteins + non-HDL(↓)  
High density lipoproteins     Emulgen B-66       cholesterol + HDL cholesterol esters +proteins  
HDL cholesterol esters + H2O   cholesterol ester hydrolase     cholesterol and fatty acids  
cholesterol + O2    cholesterol oxidase     cholest-4-en-3 + H2O2  
H2O2 + leuco dye     peroxidase      dye + H2O 
 
3.12 Data Analysis 
Data analysis was done with the Statistical Package for the Social Sciences (SPSS) software 
package version 20.0. The Student t-test for unpaired data was used to test for any statistical 
difference between two means of the cases and controls. The correlation co-efficient (r) was used 
to show the strength and direction of the association between the two linear variables. The co-
2
efficient determination (r ) was used to show the degree to which the measured variables are 
accounted for or explained by the detected observations. Pearson correlation coefficient was 
47 
 
done to test linear relationship between and within two clinical variables. A crosstab was 
performed to test relationship between and among at least three different clinical variables. 
Linear regression analysis was performed to test cause and effect relationship with or without 
CVD types. The odds ratio within study population was also determined. Univariate analysis was 
performed to test the hypothesis of magnesium effect on CVD types restricting all confounding 
factors. A p-value of ≤ 0.05 will be considered significant with a confidence interval of 95%. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
48 
 
CHAPTER FOUR 
4.0 RESULTS 
4.1 Study Population Demographics and Characteristics 
A total of one hundred and twenty-eight (128) participants were recruited for the study. The 
cases and controls were made up of comparable males/females and number. The mean ages for 
the cases and controls were also comparable. The participants included sixty (60) cases and 68 
controls. The cases were made up of 29 males and 31 females, whereas the controls were made 
up of 35 males and 33 females (Table 4.1). The mean ages for the cases and controls were 
58.35±13.76 and 53.44±16.37 years respectively and not statistically significant (p = 0.0860). 
About 73% and 56% of both the cases and controls were aged between 48 and 77 years 
respectively. On educational status of participants, thirty-five percent (35%) of cases had 
secondary education compared to 25% of the control. Majority of the cases were non-smokers 
(95%); however 35% took in alcohol. On marital status, 62% of the controls and 63% of the 
cases were married. Majority of the participants were of Christian religion of which controls 
formed 88.24% and 95% constituted the cases. Again, the majority of the participants were in 
employment of which controls and cases respectively constituted about 53% and 48%. Less than 
50% of all categories of participants undertake one form of exercise or the other. Of meal type 
preference, majority of study participants regularly take a local meal, banku and okro. 
 
 
 
 
 
 
 
49 
 
Table 0:1Distribution of general characteristics and demographics of the study population 
    Parameters                   Total (n=128)                   Male                  Female (64) 
(n=64) 
 Control Case Control Case Control Case 
(n=68) (n=60) (n=35) (n=29) (n=33) (n=31) 
   Gender  
    Male 35(51.47)* 29(48.33)     
    Female 33(48.53) 31(51.67)     
   Marital Status       
   Single 14(20.59) 2(3.33) 9(25.71) 2(6.90) 5(15.15) 0(0.00) 
   Married 42(61.76) 38(63.33) 23(65.71) 23(79.31) 19(57.58) 15(48.39) 
   Divorced 1(1.47) 9(15.00) 1(2.86) 4(13.79) 0(0.00) 5(16.13) 
   Widowed 11(16.18) 11(18.33) 2(5.71) 0(0.00) 9(27.27) 11(35.48) 
   Religion      
   Christian 60(88.24) 57(95.00) 31(88.57) 26(89.66) 29(87.88) 31(100.00) 
   Muslims 8(11.76) 3(5.00) 4(11.43) 3(10.34) 4(12.12) 0(0.00) 
   Education      
   No Formal Edu. 2(2.94) 7(11.67) 1(2.86) 2(6.90) 1(3.03) 5(16.13) 
   Basic Edu. 19(27.94) 20(33.33) 7(20.00) 11(37.93) 12(36.36) 9(29.03) 
   SHS/O-Level 17(25.00) 21(35.00) 8(22.86) 13(44.83) 9(27.27) 8(25.81) 
   HND/Diploma 11(16.18) 5(8.33) 7(20.00) 1(3.45) 4(12.12) 4(12.90) 
   Bachelor  14(20.59) 7(11.67) 9(25.71) 2(6.90) 5(15.15) 5(16.13) 
   Postgraduate  5(7.35) 0(0.00) 3(8.57) 0(0.00) 2(6.06) 0(0.00) 
Employment     
   Student 3(4.41) 1(1.67) 3(8.57) 1(3.45) 0(0.00) 0(0.00) 
   Unemployed 5(7.35) 10(16.67) 2(5.71) 2(6.90) 3(9.09) 8(25.81) 
   Employed 36(52.94) 29(48.33) 20(57.14) 19(65.52) 16(48.48) 10(32.26) 
   Retired 24(35.29) 20(33.33) 10(28.57) 7(24.14) 14(42.42) 13(41.94) 
   Smoking 0(0.00) 3(5.00) 0(0.00) 3(10.34) 0(0.00) 0(0.00) 
   Alcohol 14(20.59) 21(35.00) 14(40.00) 14(48.28) 0(0.00) 7(22.58) 
   Exercise 33(48.53) 19(31.67) 15(42.86) 8(27.59) 18(54.55) 11(35.48) 
   Age       
   18 -27 yrs 6 (8.82) 2 (3.33) 4 (11.43) 2 (6.90) 2 (6.06) 0 (0.00) 
   28 – 37 yrs  6 (8.82) 2 (3.33) 2 (5.71) 0 (0.00) 4 (12.12) 2 (6.45) 
   38 – 47 yrs  14 (20.59) 6 (10.00) 9 (25.71) 4 (13.79) 5 (31.03) 2 (6.45) 
   48 – 57 yrs  12 (17.65) 14 (23.33) 9 (25.71) 9 (31.03) 9 (15.15) 5 (16.13) 
   58 – 67 yrs 12 (17.65) 21 (35.00) 3 (8.57) 9 (31.03) 3 (9.09) 12 (38.71) 
   68 – 77 yrs  14 (20.59) 9 (15.00) 6 (17.14) 3 (10.34) 8 (24.24) 6 (19.35) 
   78 – 87 yrs 4 (5.88) 6 (10.00) 2 (5.71) 2 (6.90) 2 (6.06) 4 (12.90) 
*Number (%)   
50 
 
4.2 A comparison of the clinical and biochemical variables between cases and controls of 
the study population 
Comparing the mean values of the clinical and related biochemical parameters of the cases and 
controls of the study participants by Students t-test of unpaired data, the mean serum magnesium 
level was significantly lower (0.82±0.16) in the CVD patients as compared to the control 
(0.87±0.07) (p = 0.0210). The mean serum albumin was significantly lower in the CVD patients 
(39.10±6.69 g/L) as compared to the control (42.49±3.34 g/L) (p = 0.0003). However, the mean 
serum potassium was significantly higher in CVD patients (4.95±1.82 mmol/L) as compared to 
the controls (4.31±0.69 mmol/L) (p = 0.0081). The mean values of total cholesterol (4.77±1.51 
mmol/L), HDL (1.22±0.48 mmol/L) and LDL (2.97±1.30 mmol/L) were significantly lower in 
the CVD patients as compared to with the control group (5.32±1.33 mmol/L, 1.38±0.31 mmol/L 
and 3.43±1.01 mmol/L) with respective p-values of 0.0303, 0.0252 and 0.0263. (Table 4.2). 
 
 
 
 
 
 
 
 
 
 
 
 
 
51 
 
Table 0:2 Comparison of clinical and biochemical variables between cases and controls of the 
study population 
Parameters Units Cases (n = 60) Controls (n = 68) P-values 
 Mean±SD  Mean±SD 
Age       years      58.35±13.76      53.69±16.37       0.0860 
Mean SBP      mmHg     137.33±24.24      134.74±19.25       0.5022 
Mean DBP      mmHg     85.83±13.25      81.22±14.00       0.0589 
2
BMI Kg/m      27.29±5.79      28.79±4.88       0.1143 
2+
Mg       mmol/L     0.82±0.16      0.87±0.07       0.0210 
2+
Ca       mmol/L     2.31±0.24      2.37±0.14       0.0822 
ALB      g/L     39.10±6.69      42.49±3.34       0.0003 
2+
Adj. Ca       mmol/L     2.33±0.19      2.30±0.18       0.3610 
+
K       mmol/L     4.95±1.82      4.31±0.69       0.0081 
2-
PO4       mmol/L     1.32±0.31      1.40±0.19       0.0050 
CK      mmol/L     238.45±304.08      220.28±219.06       0.0107 
Tchol      mmol/L     4.77±1.51      5.32±1.33       0.0303 
TG      mmol/L     1.17±0.73      1.45±0.93       0.0629 
HDL      mmol/L     1.22±0.48      1.38±0.31       0.0252 
LDL      mmol/L     2.97±1.30      3.43±1.01    0.0263 
VLDL      mmol/L     0.57±0.33      0.70±0.54       0.1084 
FBG      mmol/L     6.45±3.00      6.03±3.94 0.0256 
2+ 2+
Ca / Mg       2.84±0.69      2.76±0.25       0.3739 
SBP: Systolic Blood Pressure; DBP: Diastolic Blood Pressure; BMI: Basal Metabolic Index; Mg2+: Magnesium ion; 
Ca2+: Calcium ion; ALB: Albumin; Adj. Ca2+: Adjusted Calcium ion; K+: Potassium ion; PO 2-4 : Phosphate ion; CK: 
Creatine Kinase; Tchol: Total Cholesterol; TG: Triglycerides; HDL: High Density Lipoprotein; LDL: Low Density 
Lipoprotein; VLDL: Very Low Density Lipoprotein; FBG: Fasting Blood Glucose. Significance at p< 0.05 
 
4.3 Cross tabulation 
All observations were assumed to be independent in the cross tabulation analysis. This analysis 
showed the parametersthat had strong evidence against the null hypothesis (Table 4.3).The null 
hypothesis was:No difference between serum magnesium levels and related biochemical 
parameters.  This means that by relating the analysis of Chi square to the likelihood ratio of the 
cardiovascular diseases, a stronger relationship was observed. 
 
 
 
52 
 
Table 0:3Cross Tabulation showing significant p-values 
Crosstab p-value(s) 
Chi Square Likelihood Ratio Linear by Linear Assoc. 
2+
Agecat x BMIcat x Mg cat total 0.026 0.017 0.051 
2+
ALBcat x BMIcat x Mg cat1 0.029 0.023 0.920 
2+
FBGcat x Agecat x Mg cat total 0.040 0.033 0.006 
2+
Tchol x Gender x Mg cat 0.035 0.032 - 
2+
Age x Gender x Mg cat2 0.022 0.019 - 
2+
Age x Gender x Mg cat total 0.035 0.030 - 
2+ 2+
Adj. Ca  x DBP x Mg cat2 0.011 0.010 0.001 
2+ 2+
Adj. Ca  x DBP x Mg cat total 0.038 0.015 0.037 
2+
HDLcat x DBPcat x Mg cat2 0.026 0.033 0.048 
2+
Categories mean the parameter has been stratified: Mg catas low = below reference range (< 0.70 mmol/L), normal 
= within reference range (0.70 – 1.00 mmol/L) and high = above reference range (> 1.00 mmol/L). BMIcat was 
2 2 2
stratified as underweight (16 – 18.5 Kg/m ), normal weight (18.5 – 25 Kg/m ), overweight (25 – 30 Kg/m ), 
2 2
moderately obese (30 – 35 Kg/m ) and severely obese (35 – 40 Kg/m ). Age was stratified in the range of ten 
years as (18 – 27), (28 – 37), (38 – 47), (48 – 57), (58 – 67), (68 – 77) and (78 – 87). ALBcat was categorized as 
low = below reference range (< 35 g/L), normal = within reference range (35 – 50 g/L) and high = above reference 
range (> 50 g/L). FBGcat was categorized as low = below reference range (< 4.1mmol/L), normal = within 
reference range (4.1 – 5.9mmol/L) and high = above reference range (>5.9mmol//L). HDLcat was categorized as 
low = below reference range (< 1.03 mmol/L), normal = within reference range (1.03 – 1.55 mmol/L) and high = 
above reference range (> 1.55mmol//L). DBPcat was categorized as low = below reference range (< 70 mmHg), 
normal = within reference range (70 – 80 mmHg) and high = above reference range (> 80 mmHg). Significance at 
p< 0.05 
 
 
2+
4.4 Mg  stratification of the study population 
About 13% increase of CVD prevalence occurred in patient with low serum magnesium ions 
2+ 2+ 2+
(Mg ) unlike those with high serum magnesium ions (Mg ). Magnesium (Mg ) stratification 
(Table 4.5) showed a significant influence on mean systolic and diastolic blood pressures, basal 
metabolic index, albumin, potassium, total cholesterol and low density lipoprotein. 
 
 
 
 
 
53 
 
 
 
 
 
 
 
 
0 
 
 
2+
Table 0:4Clinical variables stratified by Mg categories 
 
2+ 2+ 2+
 LowMg  NormalMg  HighMg  
Parameters Cases   *Controls  Cases Controls P-value Cases  Controls  P-value 
of study (n = 8) (n = 1)  (n = 48)  N = (65) (n = 4) (n = 2) 
Age  59.45 ±12.5 61 58.20±11.95 53.44±16.37 0.0908 58.25±23.99 52.34±11.31 0.7671 
Mean SBP 137.75±18.4 130 139.28±25.9 129.93±19.2 0.0297 120±7.79 129.37±1.41 0.1859 
MeanDBP 86.08±14.1 82 87.08±13.10 80.23±14.00 0.0094 83.5±17.29 79.78±2.12 0.7890 
BMI 26.42±6.5 30 26.35±4.84 28.31±4.88 0.0364 23.40±1.63 28.23±0.49 0.0176 
2+
Ca  2.30±0.5 2.34 2.33±0.14 2.37±0.14 0.1361 2.39±0.11 2.38±0.03 0.9105 
ALB 38.82±8.7 41 39.15±6.35 42.34±3.34 0.0008 41.75±2.36 42.45±1.41 0.7275 
2+
Adj. Ca  2.32±0.4 2.32 2.34±0.12 2.31±0.18 0.3188 2.35±0.06 2.31±0.06 0.4844 
+
K  4.99±1.3 3.5 5.12±2.06 4.29±0.69 0.0030 5.15±1.42 4.22±0.14 0.4325 
2-
PO4  1.31±0.3 1.35 1.28±0.22 1.32±0.19 0.3033 1.70±0.81 1.34±0.02 0.5854 
**CK 221.2±423.4 139 219.2±302.9 200.2±219.1 0.7003 192.5±168.4 205.2±448.3 0.9590 
Tchol 4.56±1.23 4.39 4.65±1.28 5.23±1.33 0.0217 4.53±1.07 5.21±1.44 0.5401 
TRL 1.10±0.50 1.11 1.07±0.78 1.33±0.93 0.1190 1.04±0.25 1.30±0.81 0.5490 
HDL 1.22±0.35 1.28 1.29±0.52 1.34±0.31 0.5252 1.02±0.21 1.34±0.24 0.1652 
LDL 2.80±1.08 2.60 2.81±1.13 3.42±1.01 0.0032 3.04±0.95 3.43±1.32 0.6914 
VLDL 0.50±0.23 0.51 0.49±0.36 0.64±0.54 0.0979 0.48±0.11 0.63±0.36 0.4430 
FBG 6.50±2.48 15.07 6.57±3.45 6.18±3.94 0.5849 5.20±0.95 6.16±14.35 0.8854 
2+ 
*The p-value could not be determined for the low Mg because only one of the control subject recorded a low value.Magnesium ion categories 
mean the parameter has been stratified as low = below reference range (< 0.70 mmol/L), normal = within reference range (0.70 – 1.00 mmol/L) and high = 
above reference range (> 1.00 mmol/L).Significance at p< 0.05 
**There were some outliers within the CK values of both the cases and controls thereby driving the SD figures higher than expected. 
 
54 
 
4.5 Association between Magnesium and biochemical variables in the study population
The Pearson’s Product Moment Correlation test revealed a significantly positive association 
+ 2-
between serum magnesium level with Ca, ALB, K ,PO4  and HDL, r = 0.264, 0.220, 0.216, 
0.187, 0.184  (Table 4.5). 
 
Table 0:5Association between Magnesium and biochemical variables in cases 
Correlates Pearson Correlation Pearson Coefficient P- value (two 
2
Coefficient (r) determination (r ) tailed) 
2+ 2+
Mg  and Ca  0.264 0.0696 0.003 
2+
Mg  and ALB 0.220 0.0484 0.013 
2+
Mg  and HDL 0.184 0.0339 0.038 
2+ 2- 
Mg  and PO4  0.187 0.0350 0.034 
2+ +
Mg  and K  0.216 0.0467 0.077 
Significance at p< 0.05 
4.6 Association between Magnesium abnormality and cardiovascular disease 
Magnesium abnormalities (both low and high) were positively associated with CVD in Table 
4.6. Even though the trend of higher odds of outcome persisted when the exposed group was 
treated as those having only high magnesium levels, the odds ratio was not statistically 
significant (Table 4.6.1).  
 
Table 0:6Odds ratio showing Magnesium abnormality (both high and low levels) and 
cardiovascular disease 
Unadjusted Odds CVD Controls (-) Odds Ratio =5.4167 (1.4484 – 20.2569) 
 Cases (+) Yates X2 = 6.06, p-value: 0.0138;   
                    Corrected for continuity. 
Magnesium ion (Mg2+) 12 3 Fisher exact test two tail p-value = 0.0111 
Abnormal (High or Low) 
 
Magnesium ion (Mg2+)  48 65 
Normal 
Significance at p< 0.05 
55 
 
Table 0:6.1Odds ratio of abnormal Mg (high) in the study population 
 Exposed Unexposed Total Proportion Exposed 
 
Cases 3 57 60 0.0500 
     
Controls 2 66 68 0.0294 
Total           5                    123 1280.0391 
   
Point Estimate [95% confidence Interval] 
Odds Ratio 1.736842 0.1911334         21.38132 (exact) 
Attr. frac. ex. 0.4242424 -4.231948          0.953230 (exact) 
Attr. frac. pop 0.0212121 
 
2 2
Chi  (1) =   0.36   Pr>Chi  =   0.5485 
Unexposed had both low and normal Mg levels; whilst exposed had only high Mg levels 
4.7 Adjusted Odds Ratio (OR) 
With an adjusted OR from binary logistics (table 4.7) and confounding variables e.g. SBP, BMI 
2+
controlled and an adjustment made as SBP increment of 10 plus a BMI increment of 5; Mg  
categories were seen to be associated with phosphate categories, adjusted calcium, CK 
categories, DBP categories, ALB categories and Tchol categories. 
 
 
 
 
 
 
 
 
 
 
56 
 
Table 0:7Adjusted odds ratio (binary logistics) 
 Adjusted odds by binary logistic regression** Parameters 
 
2-
 Controls (n = 47) 0.030 (-4.210 to -2.340);  Covariate: SBP 10, BMI 5, PO4 Cat 
A* p-value = 0.021  
2+
Cases (n = 59) 0.073 (-4.060 to -1.940);  Dependent: Mg new cat 
p-value = 0.017  
2+
 Cases (n = 59) 0.074 (-4.043 to -1.920);  Covariate: SBP 10, BMI 5, Adj.Ca Cat 
B p-value = 0.017  
2+
Controls (n = 52) 0.030 (-4.205 to -2.534);  Dependent: Mg new cat 
p-value = 0.019 
+
 Cases (n = 59) 0.073 (-4.060 to -1.852);  Covariate: SBP 10, BMI 5, K Cat 
C p-value = 0.016  
2+
 Controls (n = 52) 0.030 (-4.205 to -2.587);  Dependent: Mg new cat 
p-value = 0.021  
*CK categories, DBP categories, ALB categories and Tchol categories gave the same odds and 
p-value but confidence interval was different. CK categories (CI=-4.060 to -1.658); DBP 
categories (CI = -4.060 to -2.005); ALB categories (CI = -4.205 to -2.408. Tchol (CI= -4.174 to -
2.501). Significance at p< 0.05 
**Adjusted odds controlled significant confounders from section 4.6; however, SBP and BMI 
were found to be significant confounders when OR was adjusted. 
4.8 Linear regression analysis 
This analysis was performed to test the hypothesis about the cause and effect relationship (s) that 
existed between magnesium and other biochemical parameters (Table 4.8) in the study with or 
without CVD types, having observed the trend in section 4.6 to 4.7. 
Table 0:8 Linear Regression 
Parameters  With Rule (CVD cases) Without Rule 
2+
Dependent variable: Mg cat   
Independent variable   
categories: Age, SBP, DBP, P = 0.013 P = 0.013 
2+ + 2-
BMI, Adj. Ca , K , PO4 , CK, 
ALB, TRL, HDL, LDL, 
VLDL, FBG. 
2+
SBP: Systolic Blood Pressure; DBP: Diastolic Blood Pressure; BMI: Basal Metabolic Index; Mg : Magnesium ion; 
Ca2+: Calcium ion; ALB: Albumin; Adj. Ca2+: Adjusted Calcium ion; K+: Potassium ion; PO 2-4 : Phosphate ion; CK: 
Creatine Kinase; Tchol: Total Cholesterol; TG: Triglycerides; HDL: High Density Lipoprotein; LDL: Low Density 
Lipoprotein; VLDL: Very Low Density Lipoprotein; FBG: Fasting Blood Glucose. Significance at p< 0.05 
CVD = cardiovascular type. With rule: CVD cases selected; without rule: no preference made 
 
57 
 
4.9 Univariate analysis 
This analysis in Table 4.9 restricted and accounted for confounding variables thereby taking 
2+ 
Mg only and summarizing its influence on CVD having observed the trend in section 4.8. 
 
Table 0:9Univariate Analysis 
Parameters Hypothesis Testing 
2+
Dependent variable: Mg   
Fixed factor variable: Agecat and Gendercat Fdf, α = 8.069 
Covariate variable: CVD Types  
2+
Random factor variable:  Age, SBP, DBP, BMI, Adj. Ca ,                 P = 0.001 
+ 2-
K , PO4 , CK, ALB, TG, HDL, LDL, VLDL, FBG. 
SBP: Systolic Blood Pressure; DBP: Diastolic Blood Pressure; BMI: Basal Metabolic Index; Mg2+: Magnesium ion; 
Ca2+: Calcium ion; ALB: Albumin; Adj. Ca2+: Adjusted Calcium ion; K+: Potassium ion; PO 2-4 : Phosphate ion; CK: 
Creatine Kinase; Tchol: Total Cholesterol; TG: Triglycerides; HDL: High Density Lipoprotein; LDL: Low Density 
Lipoprotein; VLDL: Very Low Density Lipoprotein; FBG: Fasting Blood Glucose. Significance at p< 0.05 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
58 
 
CHAPTER FIVE 
5.0 DISCUSSION AND CONCLUSION 
5.1 DISCUSSIONS 
5.1.1 Serum Magnesium levels and CVDs 
Magnesium is a typical macro element that is associated with cardiovascular related diseases 
(Ishimura et al., 2007; Lee et al., 2005; Kieboom et al., 2016) but this conflicts other studies 
(Khan et al., 2010). In this study, a report on baseline information of serum magnesium in the 
studied Ghanaian cardiovascular disease population and its impact on clinical and biochemical 
variables showed that a 13.33% increase risk of CVD prevalence in the participants with low 
magnesium was consistent with similar studies (Kieboom et al., 2016). Notwithstanding, meta-
analysis elsewhere (Ford, 1999 & Reunanen, 1996) found an increased risk of cardiovascular 
diseases (Bernardin et al., 2005). Ford, (1999) used hazard ratio and found magnesium 
concentrations to have an indirect relationship with all-cause mortality and mortality occasioned 
by ischemic heart disease. Although studies reported by Reunanen (1996) found raised level of 
serum copper and low level of serum zinc to be related to elevated cardiovascular mortality, no 
such relationship was found with serum calcium and magnesium and associated mortality 
predisposition. Nevertheless, the current research work rather shared similar thoughts with 
Kieboom et al., (2016) depicting serum magnesium levels to be considerably reduced in CVDs 
in comparison to healthy controls. This results was also consistent with several studies 
(Alexander et al., 2008; Spiegel, 2011; Covic, 2010; Kanbay, 2010) especially among women 
and the elderly (Whang, 1987; Touitou  et al., 1987).  Low magnesium levels have been shown 
to cause damage to the endothelium and thereby could lead to cardiovascular diseases since 
magnesium promotes vasodilation, reduced vascular resistance, and lower systemic and coronary 
59 
 
blood flow and pressure (Baker et al., 2009) as it generates a pro-inflammatory, prothrombotic, 
and pro-atherogenic environment that might lead to the onset of CVD (Maier et al., 2004). In 
myocardial tissues, the ability of magnesium to antagonize calcium activity during ischaemia 
limits infarct size; reduces coronary artery spasm, and limits post-infarction oxidative damage 
(Leor, 1995). Magnesium deficiency was reported to raise blood pressure in animal models and 
its supplementation had led to the avoidance of raised blood pressure. 
 
All CVD types of interest e.g. CCF, IHD, HHD and Stroke had decreased magnesium levels in 
this study. The benefits of magnesium in cardiovascular patients include opposing release of 
glutamate, blockade of n-methyl d-aspartate receptor, resistive action of calcium channel, and 
maintenance of blood flow to the cerebral region (Muir, 2002). Even though the classification of 
cardiovascular mortality is heterogenic (Kieboom et al. 2016) with an inclusion of non - 
atherosclerotic outcomes and the heterogeneity often made it difficult to study associations 
underlying CVD pathophysiologies, the study was able to use all CVD types of congestive 
cardiac failure, hypertensive heart disease, cerebrovascular accident (Stroke) and ischaemic heart 
disease with the help of linear regression and univariate analytical tools. In this study, serum 
magnesium levels were significantly associated with or without CVD as the preferred option in 
our model (p = 0.013). One striking resemblance was it being withheld even after compensatory 
adjustment and this was consistent with a similar trend in the study conducted by other 
researchers (Lee et al., 2005). 
 
5.1.2 Association between Magnesium and biochemical variables in the study population 
The study provided information for the first time in Ghana on the serum magnesium level in 
cardiovascular disease persons and how an adjusted odds ratio with systolic blood pressure 
60 
 
(SBP) increments of ten (10) and BMI increment of five (5) could make magnesium levels 
closely relate with phosphate, calcium, creatine kinase (CK), diastolic blood pressure (DBP), 
albumin and total cholesterol. Finally, the hypotheses that; (1) there were no differences in serum 
magnesium and other biochemical factors and (2) that there were no differences between CVD 
cases and controls even after controlling for confounders were tested and found consistent with 
existing literature (Lee et al., 2005 & Kieboom et al., 2016), in that there were significant 
statistical differences. Results from the odds ratio showed that when confounders (e.g. SBP and 
BMI) were controlled and or adjusted, magnesium levels were associated with high density 
lipoprotein, albumin, phosphate, calcium and potassium levels.  
 
In the present study, albumin, calcium, high density lipoprotein, phosphates and potassium 
influenced magnesium in CVD cases. Serum potassium levels were found to have a significant 
predictive value for hypomagnesaemia and this was consistent with other research work 
(Djagblatey et al., 2016). High serum potassium has been found elsewhere to protect against 
hypertensive and sodium-induced endothelial dysfunction independent of blood pressure 
(Sugimoto et al., 1988; Volpe et al., 1990). Intravenous potassium ameliorates hypertensive 
endothelial dysfunction in humans (Taddei et al., 1994). This effect is lessened by N-
monomethyl-L-arginine a competitive nitric oxide (NO) synthase inhibitor implicating the NO 
pathway. Potassium partly mediates vasodilation via strong inwardly rectifying potassium 
channels and the sodium-potassium-ATPase pump of vascular smooth muscle cells (Dawes et 
al., 2002). This might be important when NO bioavailability is low. Potassium blunts 
angiotensin-II–induced vasoconstriction (Novak and Harrison; 1973). Hence it was increasingly 
apparent that endothelial dysfunction was associated with a worse prognosis in cardiovascular 
disease (Suwaidi et al., 2000; Perticone  et al., 2001). Potassium also has protective effects on 
61 
 
acute myocardiac infarction. Ischaemic myocardium extrudes potassium, causing 
hypopolarization and reducing the arrhythmic threshold (Harris et al., 1954; Grumbach  et 
al.,1954; Gettes  et al., 1966). Several large studies have shown an inverse relationship between 
blood pressure and potassium intake (Ascherio et al., 1996; Geleijnse  et al., 1996). This 
antihypertensive effect may be mediated by increased natriuresis, vasodilation, heightened 
baroreflex sensitivity, and reduced cardiac sensitivity to catecholamines and angiotensin II 
(Barri  & Wingo, 1997). However, concurrent repletion of magnesium with potassium with 
aldosterone blockade increases cellular potassium uptake and replenish tissue levels of both 
cations (French et al., 1984). Potassium supplements and other potassium-sparing diuretics do 
not confer the same benefits (Farquharson  & Struthers, 2002). High potassium intake reduces 
the risk of stroke (Khaw & Barret-Connor, 1987; Gillman et al., 1995). However, potassium-rich 
diets tend to be low in sodium and high in anti-oxidants, fiber, and magnesium possibly 
confounds the issue. 
 
The serum magnesium concentration as noted in this study, also, positively correlated with the 
serum concentration of other biochemical factors such as albumin, potassium, calcium, 
phosphorus and HDL in cardiovascular disease patients (Table 4.3) and these were consistent 
with de Baaij et al., (2012). In their study, de Baaij et al., (2012) observed atherogenic lipid 
profile characterized by increased total cholesterol, LDL cholesterol in newly diagnosed CVD. 
Low magnesium level and dyslipidemia observed in the current study might be predictive risk 
factors for CVD, thereby suggesting that magnesium supplementation, may prove to be 
beneficial to reduce the risk of CVD. A positive correlation between the serum magnesium and 
albumin may be expected in CVD, because the serum magnesium concentration includes 
complexed or protein-bound fractions (Ishimura et al., 2007). Depending on the nature of 
62 
 
binding, there could possibly be spectator species that might lead to reduced states of these 
compounds. Hypoalbuminemia in CVDs has been attributed to a variety of factors, including 
exogenous albumin loss, albumin distribution, catabolism rate of proteins, and the presence of 
inflammatory cytokines (Don & Kaysen, 2000 & Cesari et al., 2003). Serum albumin had been 
considered a surrogate marker of inflammatory status. However, controlling for inflammatory 
markers in a study alone by Williams et al., (2008), had no effect on the association between 
serum albumin concentration and the incident of heart failure risk, suggesting that inflammatory 
status alone does not explain the albumin-heart failure link entirely (Williams et al., 2008). 
Another alternative explanation was co-morbidities being associated with the development of 
heart failure that was associated with worsening serum albumin profile. Koch (2002), Huijgen et. 
al (2000), Chernow (1989) and their co-workers found no correlation between magnesium levels 
and serum albumin levels. However, in this study, inferential statistics revealed an association 
between magnesium and albumin which was consistent with other studies (Swaminathan, 2003). 
Hypomagnesemia, on the other hand, is being known to be frequently linked with hypokalemia 
(de Baaij et al., 2012). Hypokalemia is induced when the rennin-aldosterone-angiotensin system 
and sympathetic nervous system are activated during a heart failure. High intake of diuretics also 
aggravates hypokalemia and heightens neuro-hormonal activation (Cleland et al., 1987). 
Abnormal cellular ion transport resulting in altered membrane control over intracellular calcium 
might also be related to essential HHD. The free intracellular calcium concentration determines 
the tension in vessel smooth muscle cells, and thus peripheral vascular resistance (Chlumsky, 
1993). In addition, studies have linked the fact that when there is excessive deposition in the 
vascular system it results in increased hardening of the arteries. This further leads to the 
elevation of the index of the mass of the left ventricle thereby contributing to the cause of carotid 
63 
 
vessel disease (Kendrick et al., 2010; Meng et al., 2010) with higher serum phosphorus 
concentrations.  
 
5.2CONCLUSIONS 
In conclusion, the cardiovascular disease patients and controls in this study were adult with 
majority having secondary school education and of Christian religious background. The study 
established statistically that there was a significant relationship between mean serum magnesium 
levels in the controls and cases in that magnesium level in the cases were lower in comparison to 
the controls. Despite this significance, further statistical analysis in accounting for confounding 
variables with or without rules established that there was a significant relationship between 
serum magnesium levels in the studied cases and controls. The study also established that serum 
magnesium level was positively associated with other biochemical parameters measured. The 
biochemical parameters such as serum potassium, phosphorous, HDL, LDL and albumin, FBG 
and CK levels were found to be significantly different between CVD patients and apparently 
healthy controls by being higher in the cases. The study in addition established a 13.33% 
increased risk of CVD prevalence in the participants with low magnesium levels. The study 
further showed that an adjusted odds ratio of 5.42 with systolic blood pressure increments of ten 
(10) and body mass index increment of five (5) could make magnesium levels closely relate with 
potassium, phosphate, calcium, CK, DBP, albumin and total cholesterol as determinants of risk 
of cardiovascular disease. 
 
 
64 
 
5.3 LIMITATIONS 
The analysis measured total serum magnesium levels and not metabolically ionized magnesium 
as the methods required for the latter was not readily available. Although, the dry chemistry 
analytical method employed by the Vitrios 5.1 FS analyzer is used routinely in the hospital to 
determine serum concentration of magnesium, atomic absorption spectrophotometry method is 
the gold standard method in research for analysis of the magnesium. Serum troponins have been 
found in recent times to have excellent sensitivity and specificity and are superior to creatine 
kinase (CK-MB) as markers for myocardial dysfunctions but could not be included in the panels 
of biochemical analytes measured in the study due to its high financial cost of measurement. The 
effect of magnesium and the various biochemical parameters in the presentation of the various 
CVD cases sampled such as congestive heart failure, ischaemic heart disease, hypertensive heart 
disease and stroke should have been explored using statistically adequate numbers of each 
condition for comparison. Finally there were insufficient financial and material resources 
available for a larger sample size. 
 
5.4 RECOMMENDATIONS 
Considering that CVD has long term complications, it will be of significant interest to investigate 
extensively on magnesium and its contribution to the disease phenotype in CVD for point of care 
diagnostics.  The gold standard of atomic absorption spectrophotometric method is to be used to 
see if similar trend can be established. Parathyroid hormone should be included in further work 
for further insights to the interplay among the electrolytes and the biochemical parameters. This 
study could be replicated with larger study population for stronger case for clinical policy 
formulation.  
 
65 
 
Since hormonal levels play crucial roles in biochemical parameters, analyzing hormonal levels in 
the current study might have been an added advantage. Also, the analysis measured total serum 
magnesium levels and not metabolically ionized magnesium as the methods required for the 
latter was not readily available. Although, this was the first report in the Ghanaian population, 
much work is needed in this regard. Also, considering that CVD has long term complications, it 
will be of significant interest to investigate extensively on magnesium and its contribution to the 
disease phenotype in CVD.  When this is widely done, it would aid in point of care diagnostics 
for faster decision making in CVD management. The effect of magnesium and the various 
biochemical parameters in the presentation of the various CVD cases sampled should be 
explored in further studies using statistically adequate numbers of each condition for 
comparison. 
 
 
 
 
 
 
 
 
 
 
 
 
 
66 
 
REFERENCES 
Abanilla, P. K. A., Huang, K. Y., Shinners, D., Levy, A., Ayernor, K., Aikins, G. A., &  
            Ogedegbe, O. (2011). Cardiovascular prevention in Ghana: feasibility of a faith based  
           organizational approach. Bulletin World Health Organisation. 89(9), 648-656   
Abbott, R. D., Ando, F., Masaki, F. H., Tung, K. H., Rotriguez, B. L., Petrovitch, H., Yano, K. & 
Curb, J. D. (2003). Dietary magnesium intake and the future risk of coronary heart 
disease (Honlulu Heart Programme). Am J Cardiol., 92(6), 665 – 669.  
Acquaye, J. A. (1991). Standard Operating Procedure for performing venepuncture in the KBTH.  
Haematology Laboratory Manual.   
Adamopoulos, C., Pitt, B., Sui, X., Love, T. E., Zannad, F., & Ahmed, A. (2009). Low serum  
magnesium and cardiovascular mortality in chronic heart failure: a propensity-matched 
study. International journal of cardiology, 136(3), 270-277. 
Addo, J., Smeeth, L., Leon, D. A. (2007). Hypertension in sub-saharan Africa: a systematic  
review. Hypertension, 50, 1012-1018 doi: 10.1161/hypertensionaha.107.093336 pmid: 
17954720. 
Agarwal, S. (2016). Magnesium Deficiency and Cardiocascular Disease. The Internet Journal of  
 Cardiology, 12(1), 1-8. 
Agyemang, C., Attah-Adjepong, G., Owusu-Dabo, E., De-Graft Aikins, A., Addo, J., Edusei, A.,  
67 
 
K., Nkum, B. C., & Ogedegbe, G. (2012). Stroke in Ashanti region of Ghana. Ghana 
Med J., 46 (2 Suppl):12-17.  
Agyemang, C. (2015). Cardiovascular diseases in poor resource settings (Accessed on 2015 May  
23). Available online: http://globalmedicine.nl/issues/gm10/article6.pdf 
Agyei-Mensah,  S., & de-Graft Aikins,  A. (2010).  Epidemiological transition and the double  
burden of disease in Accra, Ghana.J Urban Health, 87, 879-897. [PMC free 
article][PubMed] 
Allain, C.C., et al. (1974). Enzymatic determination of total cholesterol in serum. Clin. Chem.  
            20, 470 
Alegría-Ezquerra, E., González-Juanatey, J. R., González-Maqueda, I. (2006). "Hypertensive  
heart disease: a proposed clinical classification". Revista Española de Cardiología (in 
Spanish). 59(4), 398–399. doi:10.1016/S1885-5857(06)60781-0. PMID 16709396 
Alexander, R., Hoenderop, J., & Bindels, R. (2008). Molecular determinants of magnesium 
homeostasis: insights from human disease. J Am SocNephrol, 19, 1451-1458. 
Al-Hadi, H. A. & Fox, K. A. (2009). Cardiac markers in the early diagnosis and management of  
patients with acute coronary syndrome. Sultan Qaboos Univ Med J., 9(3), 231–246. 
Amighi, J., Sabeti, S., Schlager, O., Mlekusch, W., Exner, M., Lalouschek, W., . . . Schillinger, 
M. (2004, January). Low serum magnesium predicts neurological events in patients with 
advanced atherosclerosis. Stroke, 35(1), 22-27. 
Ambrose, J., & Singh, M. (2015). Pathophysiology of coronary artery disease leading to acute  
68 
 
coronary syndromes, F1000 Prime report, 7. doi: 10 127031P7-08 issn 2057-7599 
Anderson, T. W., Le Riche, W. H., & MacKay, J. S. (1969). Sudden death and ischemic heart  
disease. Correlation with hardness of local water supply. N Engl J Med.,280(15), 805–
807. [PubMed] 
Antman, E. M. (1996). Magnesium in acute myocardial infarction: Overview of available  
evidence. American Heart Journal, 132(2), 487-495. 
Assaadi, F.(2010). Hypomagnesia:an evidence based approach to clinical cases. Iranian Journal  
of Kidney disease, 4(1), 13-19. 
Ascherio, A., Hennekens, C., & Willet, W. (1996). Prospective study of nutritional factors, blood 
pressure, and hypertension among US women. Hypertension, 27, 1065-1072. 
Badii, C. (2017). Hypertensive heart disease. www.healthline.com/health/hypertensive-heart- 
disease (Accessed on 15 April 2017) 
Ba id e n,  F . ,  Ho dgso n,  A. ,  B ink a ,  F .  N .  ( 2006). Demo graphic surveillance  
sites and emerging challenges in international health.  Bull World Health 
Organ.,84(3), 161–256. 
Baker, W., Kluger, J., White , C., Dale, K., Silver, B., & Coleman, C. (2009). Effect of 
magnesium L-lactate on blood pressure in patients with an implantable cardioverter 
defibrillator. Ann Pharmacother, 43, 569-576. 
Barbagallo, M., & Dominguez, L. (2007). Magnesium metabolism in type 2 diabetes mellitus, 
metabolic syndrome and insulin resistance. Arch BiochemBiophys, 458, 40 - 47. 
69 
 
Barri, Y., & Wingo, C. (1997). The effects of potassium depletion and supplementation on blood 
pressure: a clinical review. Am J Med Sci, 314, 37-40. 
BeLue, R., Okoror, T. A., Iwelunmor, J., Taylor, K. D., Degboe, A.N., & Agyemang, C. (2009).  
An overview of cardiovascular risk factor burden in sub-Saharan African countries: a 
socio-cultural perspective. Global Health, 5: 10  doi: 10.1186/1744-8603-5-10 pmid: 
19772644.  
Bernadini, D., Nasulewic, A., & Mazur, A. (2005). Magnesium and microvascular endothelial 
cells: a role in inflammation and angiogenesis. Front Biosci, 10, 1177-1182. 
Binka, F.N., Ngom, P., Phillips, J.F., Adazu, K.F., & Macleod, B. (1999). Assessing Population  
Dynamics in a Rural African Society; Findings from the Navrongo Demographic 
Surveillance System. Journal of Biosocial Science, 31, 375-391. 
Burstein, M., Scholnick, H.E. & Morfin, R. (1970). Rapid method for the isolation of       
           lipoproteins from human serum by precipitation with polyanions. J. Lipid R,es. 11, 583-  
           595.  
Cesari, M., Penninx, B., & Newman, A. (2003). Inflammatory markers and onset of 
cardiovascular events: Results from the Health ABC study. Circulation, 108, 2317-2322. 
Chakraboti, S., Chakraboti, T., Mandal, M., Mandal, A., Das, S., & Ghosh, S. (2002). Protective 
role of magnesium in cardiovascular diseases: a review. Mol Cell Biochem, 238, 163-179. 
Chernow, B., Bamberger, S., Stoiko, M., Vadnais, M., Mills, S., Hoellerich, V., & Warshaw, A.  
L. (1989). Hypomagnesemia in patients in postoperative intensive care. Chest, 95(2), 
391-397. 
Chlumsky, J. (1993). Calcium and hypertension. VnitrLek, 39, 1181-1184. 
70 
 
Chiuve, S. E., Korngold, E. C., Januzzi, J. L. Jr., Gantzer, M. L. & Albert, C. M. (2011).  
Plasma and dietary magnesium and risk of sudden cardiac death in women. Am J Clin 
Nutr., 93(2), 253–260. doi:  10.3945/ajcn.110.002253 
Chobanian, A. V., Bakris, G. L., Black, H.R., Cushman, W.C., Green, L. A., Izzo, J. L. Jr.,  
Jones, D. W., Materson, B. J., Oparil, S., Wright, J. T. Jr., & Roccella, E. J. (2003). The 
Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation 
and Treatment of High Blood Pressure: the JNC 7 report. JAMA. 289, 2560–2572.  
Cines, D. B., Pollak, E. S., Buck, C. A., Loscalzo, J., Zimmerman, G. A., McEver, R. P., ... & 
Barnathan, E. S. (1998). Endothelial cells in physiology and in the pathophysiology of 
vascular disorders. Blood, 91(10), 3527-3561. 
Cleland, J., Dargie, H., & Ford, I. (1987). Mortality in heart failure. Clinical variables of 
prognostic value. Br Heart J, 58, 572-582. 
Cleland, J., Dargie, H., Robertson , I., Robertson, J., & East , B. (1987). Total body electrolyte 
composition in patients with heart failure: a comparison with normal subjects and patients 
with untreated hypertension. Br Heart J, 58, 230-238. 
Commonwealth Health. (2016). Accessed from  http://www.commonwealthhealth.org/ 
africa/ghana/non_communicable_diseases_in_ghana on 14 August 2016 
Covic, A. (2010). Magnesium in chronic kidney disease- More than just phosphate binding. 
EuroNephrol, 4, 28-36. 
Curme, H., & Rand, R. N. (1997). Early history of Eastman Kodak Ektachem slides and  
determination of total serum cholesterol. Clinical chemistry, 20(4), 470-475. 
instrumentation. Clinical chemistry, 43(9), 1647-1652. 
J, 25, 366-368. 
71 
 
Dao, H. H., Essalihi, R., Bouvet, C., & Moreau, P. (2005). Evolution and modulation of age- 
related medial elastocalcinosis: impact on large artery stiffness and isolated systolic 
hypertension. Cardiovascular research, 66 (2), 307-317. 
Dasgupta, A., Sarma, D., & Saikia, U. K. (2012). Hypomagnesemia in type 2 diabetes mellitus.  
Indian journal of endocrinology and metabolism, 16(6), 1000. 
Dawes, M., Sieniawska, C., Delves, T., Dwivedi, R., Chowienczyk, P., & Ritter, J. (2002). 
Barium reduces resting blood flow and inhibits potassium-induced vasodilation in the 
human forearm. Circulation, 105, 1323-1328. 
de-Graft Aikins, A. (2007). Ghana’s neglected chronic disease epidemic: a developmental  
challenge. Ghana Med J,41(4), 154-159 pmid: 18464903.  
de Baaij, J. H., Hoenderop, J. G., Bindels, R. J. (2015). Magnesium in man: implications for  
health and disease. Physiol Rev., 95, 1–46. 
de Baaij, J. H., Stuiver, M., Meij, I. C., Lainez, S., Kopplin, K., Venselaar, H., ... & Hoenderop,  
J. G. (2012). Membrane topology and intracellular processing of cyclin M2 (CNNM2). 
Journal of Biological Chemistry, 287(17), 13644-13655. 
Deedwania, P., & Fonseca, V. (2005). Diabetes, prediabetes, and cardiovascular risk: shifting the 
paradigm. Am J med, 118, 939-947. 
Djagbletey, R., Phillips, B., Frank Boni, F., Owoo, C., Owusu-Darkwa, E., deGraft-Johnson, P.  
K. G., & Yawson, A. E. (2016). Relationship between serum total magnesium and serum 
potassium in emergency surgical patients in a tertiary hospital in Ghana. Ghana Med 
J.,50(2), 78–83. PMCID: PMC5012135 
Don, B. R., & Kaysen, G. A. (2000). Assessment of inflammation and nutrition in 
patients with end-stage renal disease. Journal of Nephrology, 13(4), 249-259. 
72 
 
Douban S., Brodsky M. A., Whang D. D., & Whang R. (1996). Significance of magnesium in  
congestive heart failure. American Heart Journal, 132(3), 664 – 671  
Drueke, T. B., & Lacour, B. (2007). Magnesium homeostasis and disorders of magnesium  
rd
metabolism. Comprehensive Clinical Nephrology. 3  ed. Philadelphia, PA Mosby; (136-
138) 
Euser, A. G., &  Cipolla, M. J. (2009). Magnesium sulfate treatment for the prevention of  
eclampsia: A brief review. Stroke,40(4): 1169 - 1175.  
Farquharson, C., & Struthers, A. (2002). Increasing plasma potassium with amiloride shortens 
the QT interval and reduces ventricular extrasystoles but does not change endothelial 
function or heart rate variability in chronic heart failure. Heart, 88, 475-480. 
Fawcett, W. J., Haxby, E. J., Male, D. A. (1999). Magnesium: physiology and pharmacology.  
Br J Anaesth.,83, 302–320. [PubMed] 
Fiske, C. H. and Subbarou, Y. (1925). The colorimetric determination of phosphorus. J. Biol.  
           Chem., 66, 375. 
Foley, R., Collins, A., Herzog, C., Ishani, A., & Kalra, P. (2009). Serum phosphorus levels 
associate with coronary atherosclerosis in young adults. J Am Soc Nephrol, 20, 397-404. 
Folkman, J. (1995). Angiogenesis in cancer, vascular, rheumatoid and other disease. Nature  
medicine, 1(1), 27. 
 
Folsom, A. R., Yatsuya, H., Nettleton, J. A., Lutsey, P. L., Cushman, M. & Rosamond, W. D.  
(2011). ARIC Study Investigators: Community prevalence of ideal cardiovascular health, 
by the American Heart Association definition, and relationship with cardiovascular 
disease incidence.J Am Coll Cardiol.,57(16), 1690-1696. doi: 
10.1016/j.jacc.2010.11.041. 
73 
 
Ford , E., & Mokdad, A. (2003). Dietary magnesium intake in a national sample of US adults. J 
Nutr, 133, 2879-2882. 
Ford, E. S. (1999). Serum magnesium and Ischemic heart disease; Findings from National  
Sample of US adults. International Journal of Epidemiology, 28, 645-651 
French, J., Thomas, R., Siskind, A., Brodsky, M., & Iseri, L. (1984). Magnesium therapy in 
massive digoxin intoxication. Ann Emerg Med, 13, 562-566. 
Freedman, B. I., Bowden, D. W., Ziegler, J. T., Langefeld, C. D., Lehtinen, A. B., Rudock, M.  
E., ... & Carr, J. J. (2009). Bone morphogenetic protein 7 (BMP7) gene polymorphisms 
are associated with inverse relationships between vascular calcification and BMD: the 
Diabetes Heart Study. Journal of Bone and Mineral Research, 24(10), 1719-1727. 
Gallo, L., Faniello, M. C., Canino, G., Tripolino, C., Gnasso, A., Cuda, G., Costanzo, F. S.,  
Irace, C. (2016).  Serum calcium increase correlates with worsening of lipid profile. An 
observational study on a large cohort from south Italy. Medicine (Baltimore), 95(8), 
e2774. doi:  10.1097/MD.0000000000002774 
Geiger, H & Wanner. C. (2012). Magnesium in disease. Clin Kidney J.,5(1), 25–38.  
Geleijnse, J., Witteman, J., & den Breeijen, J. (1996). Dietary electrolyte intake and blood 
pressure in older subjects: the Rotterdam study. J Hypertens, 14, 737-741. 
Gettes, L., Surawicz, B., & Kim, K. (1966). Role of myocardial K and Ca in initiation and 
inhibition of ventricular fibrillation. Am J Physiol, 211, 699-702. 
Gillman, M., Cupples, L., & Gagnon , D. (1995). Protective effect of fruits and vegetables on 
development of stroke in men. JAMA, 273, 1113-1117. 
Global Burden of Disease (GBD). (2013). Mortality and Causes of Death, Collaborators (17  
74 
 
December 2014). "Global, regional, and national age-sex specific all-cause and cause-
specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the 
Global Burden of Disease Study 2013". Lancet, 385, 117–71. doi:10.1016/S0140-
6736(14)61682-2. PMC 4340604. PMID 25530442 
Gomori, G. (1942). A modification of the colorimetric Phosphorus determination for use with a  
           photoelectric colorimeter. J. Lab. Clin. Med. 27, 955 
Gordis, L. (2009). Epidemiology: fourth edition. Philadelphia: Saunders Elsevier, 375. 
Grumbach, L., Howard, J., & Merril, V. (1954). Factors related to the irritation of ventricular 
fibrillation in the isolated heart. Circ Res, 2, 452-459. 
Grzesiak, J. J. & Pierschbacher, M. D. (1995). Shifts in the concentrations of magnesium and  
calcium in early porcine and rat wound fluids activate the cell migratory response. J Clin 
Invest., 95(1), 227–233. doi:  10.1172/JCI117644 
Gums, J. G. (2004). Magnesium in cardiovascular and other disorders. Am J Health Syst Pharm,  
61, 1569-1576.  
Gund, B.M., Jagtap, P.N., Ingale, V.B., & Patil, R.Y. (2006). Stroke: A brain attack. IOSR  
Journal of Pharmacy, 3(8), 1- 23. 
Harris, A., Bisteni, A., DiMarco, J., Brigham, J., & Firestone , J. (1954). Excitatory factors in 
ventricular tachycardia resulting from myocardial ischaemia. Science, 119, 200-203. 
Seelig, M.S. & Rosanoff, A. (2003). The magnesium factor. Avery Publishers, Ne Yor, USA. 
He, K., Liu, K., Daviglus, M. L., Morris, S. J., Loria, C. M., Van Horn, L., Jacobs, D. R. Jr.,  
Savage, P. J. (2006). Magnesium intake and incidence of metabolic syndrome among 
young adults. Circulation,113(13), 1675-1682 
Houston, M. C., & Harper, K. J. (2008). Potassium, magnesium, and calcium: Their role in both  
75 
 
the cause and treatment of hypertension. J Clin Hypertens (Greenwich),10, 3-11. 
Hu, F., Stampfer, M., Haffner, S., Solomon , C., Willet, W., & Manson, J. (2002). Elevated risk 
of cardiovascular disease prior to clinical diagnosis of type 2 diabetes. Diabetes Care, 25, 
1129-1134. 
Huijgen, H. J., Soesan, M., Sanders, R., Mairuhu, W. M., Kesecioglu, J., & Sanders, G. T.  
(2000). Magnesium levels in critically ill patients. American journal of clinical 
pathology, 114(5), 688-695. 
Ishimura, E., Okuno, S., Yamakawa, T., Inaba, M., & Nishizawa, Y. (2007). Serum magnesium  
concentration is a significant predictor of mortality in maintenance hemodialysis patients. 
Magnesium Research, 20(4), 237-244. 
James, M. (1992). Clinical use of magnesium infusions in anesthesia. Anesthesia & Analgesia,  
74(1), 129-136. 
Kadiri, S. (2005). Tackling cardiovascular disease in Africa. Brit Med J, 331, 711-712 doi:  
10.1136/bmj.331.7519.711 pmid: 16195264.  
Kadiri, S., Salako. B. (1997). Cardiovascular risk factors in middle aged Nigerians. East African  
Medical Journal, 74(5), 303-306. PubMedGoogle Scholar 
Kanbay, M., Goldsmith, D., & ErkmanUyar, M. (2010). Magnesium in chronic kidney disease: 
challenges and opportunities. Blood Purif, 29, 280-292. 
Kanemaru, K., Seya, K., Miki, I., Motomura, S., & Furukawa, K. I. (2008). Calcification of  
aortic smooth muscle cells isolated from spontaneously hypertensive rats. Journal of 
pharmacological sciences, 106(2), 280-286. 
Kao, W. H., Folsom, A. R., Nieto, F. J., Mo, J. P., Watson, R. L., Brancati, F. L. (1999). Serum  
and dietary magnesium and the risk for type 2 diabetes mellitus: the Atherosclerosis Risk 
in Communities Study. Arch Intern Med, 159, 2151–2159.  
76 
 
Kasner, S. E. & Sacco, R. L. (2013). Implications of the AHA/ASA Updated Definition of  
Stroke for the 21st Century. World Neurology: The official newsletter of world 
federation of neurology. Accessed on 06 March 2017. 
Kaye, S., McKetin, R., Duflou, J., & Darke, S. (2007). Methamphetamine and cardiovascular  
pathology: a review of the evidence. Addiction, 102 (8), 1204-1211. 
Kelsey, J. L., Whittemore, A. S., Evans, A. S., & Thompson, W. D. (1996). Methods of sampling  
oxygen acceptor. Annals of clinical Biochemistry, 6(1), 24-27. 
Kesteloot, H., & Geboers, J. (1982). Calcium and blood pressure. The Lancet, 319(8276), 813- 
815. 
Kendrick, J., Ix, J., Targher, G., Smits, G., & Chonchol, M. (2010). Relation of serum 
phosphorus levels to ankle brachial pressure index (from the Third National Health and 
Nutrition Examination Survey). Am J Cardiol, 106, 564-568. 
Kendrick, J., Kestenbaum, B., & Chonchol, M. (2011). Phosphate and cardiovascular disease. 
Adv Chronic Kidney Dis, 18(2), 113-119. 
Khan, A. M., Sullivan, L., McCabe, E., Levy, D., Vasan, R. S., Wang, T. J. (2010). Lack of  
association between serum magnesium and the risks of hypertension and cardiovascular 
disease. Am Heart J, 160(4), 715-720. doi: 10.1016/j.ahj.2010.06.036 
Khan, A., Lubitz, S., Sullivan, L., Sun, J., Levy, D., & Vasan, R. (2013). Low serum magnesium 
and the development of atrial fibrillation in the community: The Framingham heart study. 
Circulation, 127, 33-38. 
Khaw, K., & Barret-Connor, E. (1987). Dietary potassium and stroke-associated mortality: a 12-
year prospective population study. N Engl Med, 316, 235-240. 
77 
 
Kieboom, B. C., Niemeijer, M. N., Leening, M. J., van den Berg, M. E., Franco, O. H., Deckers,  
J. W., & Hoorn, E. J. (2016). Serum magnesium and the risk of death from coronary heart 
disease and sudden cardiac death. Journal of the American Heart Association, 5(1), 
e002707. 
Kircelli, F., Peter, M. E., Sevinc, O.  E., Celenk, F. G., Yilmaz, M., Steppan, S., Asci, G., Ok, E.  
& Passlick-Deetjen, J. (2012). Magnesium reduces calcification in bovine vascular 
smooth muscle cells in a dose-dependent manner.Nephrol Dial Transplant, 27(2), 514-
21.  
Koch, S. M., Warters, R. D., & Mehlhorn, U. (2002). The simultaneous measurement of ionized  
and total calcium and ionized and total magnesium in intensive care unit patients. Journal 
of critical care, 17(3), 203-205. 
Larsson, S., Orsini, N., & Wolk, A. (2012). Dietary magnesium intake and risk of stroke: A 
meta-analysis of prospective studies. Am J Clin Nutr, 95, 362-366. 
Laurant, P., & Touyz, R. (2000). Physiological and pathophysiological role of magnesium in the 
cardiovascular system: implications in hypertension. J Hypertens, 18, 1177-1191. 
Lee, D. H., Folsom, A. R., & Jacobs, D. R. (2005). Iron, zinc, and alcohol consumption and  
mortality from cardiovascular diseases: the Iowa Women's Health Study. The American 
journal of clinical nutrition, 81(4), 787-791. 
Leor, J., & Kloner, R. (1995). An experimental model examining the role of magnesium in the 
therapy of acute myocardial infarction. Am J Cardiol, 75, 1292-1293. 
Leurs, L. J., Schouten, L. J., Mons, M. N., R. Alexandra Goldbohm, R. A., & Piet A. van den  
78 
 
Brandt, P. A. (2010). Relationship between Tap Water Hardness, Magnesium, and 
Calcium Concentration and Mortality due to Ischemic Heart Disease or Stroke in the 
Netherlands. Environ Health Perspect, 118(3), 414–420. doi:  10.1289/ehp.0900782 
Levitzky, Y., Pencina, M., & D'Agostino, R. (2008). Impact of impaired fasting glucose on 
cardiovascular disease: the Framingham Heart Study. J Am Coll Cardiol, 51, 264-270. 
Liamis, G., Rodenburg, E. M., Hofman, A., Zietse, R., Stricker, B. H., & Hoorn, E. J. (2013).  
Electrolyte Disorders in Community Subjects: Prevalence and Risk Factors  
Am J Med, 126 (3), 256-263. 
Liao, F., Folsom, A., & Brancati, F. (1998). Is low magnesium concentration a risk factor for 
coronary heart disease? The Atherosclerosis Risk in Communities (ARIC) Study. Am 
Heart J, 136, 480-490. 
Lifton, R. P., Gharavi, A. G., & Geller, D. S. (2001). Molecular mechanisms of human  
hypertension. Cell, 104(4), 545-556. 
 
Lind, L., Jakobsson, S., Lithell, H., Wengle, B., & Ljunghall, S. (1988). Relation of serum 
calcium concentration to metabolic risk factors for cardiovascular disease. BMJ, 297, 
960-963. 
Lin, C. Y., Tsai P. S., & Hung Y. C. (2010). L-type calcium channels are involved in mediating  
Makgoba MW, Bos ER, Baingana FK, Hofman KJ, & Rogo KO, editors. Disease and 
mortality in Sub-Saharan Africa. Washington, DC: World Bank Group; 305–327. 
Liu, J., Grundy, S., & Wang, W. (2007). Ten year risk of cardiovascular incidence related to 
diabetes, prediabetes, and the metabolic syndrome. Am Heart J, 153, 552-558. 
Livesay, J. J. ( 2007). Cardiovascular Diseases in Africa. Tex Heart Inst J, 34, 6-7. [PMC free    
article] [PubMed] 
79 
 
Lloyd-Jones  DM., Hong  Y., Labarthe  D., (2010). American Heart Association Strategic  
 Planning Task Force and Statistics Committee Defining and setting national goals for  
cardiovascular health promotion and disease reduction: the American Heart Association's     
Strategic Impact Goal through 2020 and beyond. Circulation. 121, 586-613. 
Ma J, Folsom AR, Melnick SL, Eckfeldt JH, Sharrett AR, Nabulsi AA, Hutchinson RG, Metcalf   
PA. (1995). Associations of serum and dietary magnesium with cardiovascular disease, 
hypertension, diabetes, insulin, and carotid arterial wall thickness: the ARIC study. 
Atherosclerosis Risk in Communities Study. Journal of Clinical Epidemiology, 48(7), 
927-40. 
Macdonald, J. E & Struthers, A. D. (2004). What is the optimal serum potassium level in  
cardiovascular patients? Journal of the American College of Cardiology, 43(2), 155-161 
Maier, J., Malpuech-Brugere, C., & Zimowska, W. (2004). Low magnesium promotes 
endothelial cell dysfunction: implications of atherosclerosis, inflammation and 
thrombosis. BiochimBiophysActa, 1689, 13-21. 
Manea, M. M., Comsa, M., Minca, A., Dragos, D.& Popa, C. (2015). Brain-heart axis - Review  
Article. J Med Life, 8(3), 266–271.  
Mazzone, T., Chait, A., & Plutzky, J. (2008). Cardiovascular disease risk in type 2 diabetes 
mellitus: insights from mechanistic studies. Lancet, 371, 1800-1809. 
Mbewu A, & Jean-Claude, M. (2006). Cardiovascular disease. In: Jamison D, Feachem RG,  
Sample of US adults. International Journal of Epidemiology, 28, 645-651 
the anti inflammatory effects of magnesium sulphate. British Journal of Anaesthesia, 
104(1), 44-51  
Mbewu, A., & Mbany, J. (2015). Chapter 21: Cardiovascular Disease. In Disease and Mortality  
80 
 
in Sub-Saharan Africa (Accessed on 2015 June 13). Available online: 
http://www.ncbi.nlm.nih.gov/books/NBK2294/ 
MedicineNet (2016). Definition of cerebrovascular accident, accessed at
 http://www.medicinenet.com/script/main/art.asp?articlekey=2676 
MedicineNet (2016). Definition of heart failure, accessed at http://www.medterms.com/  
script/main/art.asp?articlekey=3672 
Mehta, P. K., Wei, J. & wenger, N. K. (2014). Ischemic heart disease in women: a focus on risk  
factors. Trends in cardiovascular medicine, 25, 140-151. doi:10-1016/j. tem. 2014. 
10.005. PMID 25453985. 
Mendis, S., Puska, P., & Norvis, B. (2011). Global Atlas on Cardiovascular disease and  
st
prevention (1  edition). Geneva: WHF and world stroke organization, 3-18. 
ISBN9789241564373 
Meng , J., Wassel, C., Kestenbaum, B., Collins , T., Criqui, M., Lewis, C., . . . Ix, J. (2010). 
Serum phosphorus levels and the spectrum of ankle-brachial index in older men: the 
Osteoporotic Fractures in Men (MrOS) study. Am J Epidemiol, 171, 909-916. 
Meyer, K. A., Kushi, L. H., Jacobs Jr, D. R., Slavin, J.,  Sellers, T. A., &Folsom, A. R. (2000).  
Carbohydrates, dietary fiber, and incident type 2 diabetes in older women. Am J Clin 
Nutr,71(4), 921-930 
Mocumbi, A. O. (2012). Lack of focus on cardiovascular disease in sub-Saharan Africa.  
Cardiovasc Diagn Ther, 2, 74-77. [PMC free article] [PubMed] 
Montezano, A. C., Zimmerman, D., Yusuf, H., Burger, D., Chignalia, A. Z., Wadhera, V., van  
81 
 
Leeuwen, F. N. & Touyz, R. M. (2010). Vascular Smooth Muscle Cell Differentiation to 
an Osteogenic Phenotype Involves TRPM7 Modulation by Magnesium. Hypertension, 
56, 453-462. 
Moran, A. E., Tzong, K. Y., Forouzanfar, M. H., Roth, G., Mensah, G. A., Majid, E., Murray, C.  
J. L., & Naghavi, M. (2014). Variations in Ischemic Heart Disease Burden by Age, 
Country, and Income: The Global Burden of Diseases, Injuries and Risk Factors 2010 
Study. Glob Heart, 9(1), 91–99. doi:  10.1016/j.gheart.2013.12.007 
Muir, K. (2002, November). Magnesium in stroke treatment. Postgrad Med J, 78(925), 641-645. 
Mussoni, L., Sironi, L., Tedeschi, L., Calvio, A. M., Colli, S., & Tremoli, E. (2001). Magnesium  
inhibits arterial thrombi after vascular injury in rat: in vivo impairment of coagulation. 
Thrombosis and haemostasis, 86(05), 1292-1295. 
Nakaigawa, Y., Akazawa, S., Shimizu, R., Ishii, R., Ikeno, S., Inoue, S., & Yamato, R. (1997).  
Effects of magnesium sulphate on the cardiovascular system, coronary circulation and 
myocardial metabolism in anaesthetized dogs. British journal of anaesthesia, 79(3), 363-
368. 
Nathan, D. M., Davidson, M.B., DeFronzo, R. A., Heine, R. J., Henry, R. R., Pratley, R. & 
Zinman, B. (2007). Impaired Fasting Glucose and Impaired Glucose Tolerance: 
Implications for care. Diabetes Care, 30(3), 753-759.  
National Heart, Lung and Blood Institute (1998). Clinical Guidelines on the Identification,  
Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report. 
National Institute of Health (NIH). (2016). U. S. Department of health and human services.  
Bethesda, New York, united states 
National Institutes of Health (NIH), Office of Dietary Supplements. (2005). What are some of  
82 
 
the current issues and controversies about magnesium? 2005 http:// 
th
ods.od.nih.gov/factsheets/magnesium.asp#h7…Retrieved 16  November, 2016 
NHLBI, 1998. Executive Summary. Clinical Guidelines on the Identification, Evaluation, and  
Treatment of Overweight and Obesity in Adults: The Evidence Report. National Heart, 
Lung, and Blood Institute. xi–xxx 
Nolte, E.E., & McKee, M. (2008). Caring for people with chronic conditions : a health system  
perspective. European Observatory on Health Systems and Policies Series, XXI, 259 p. 
http://doi.org/ISBN 978 92 890 4294 9 
Novak, L., & Harrison, C. J. (1973). Abnormalities of cellular potassium concentration in 
uncompensated and compensated congestive heart failure. Mayo Clin Proc, 48, 107-113. 
Oduro, A. R., Wak, G., Azongo, D., Debpuur, C., Wontuo, P., Kondayire, F. et al. (2012). Profile  
of the Navrongo Health and Demographic Surveillance System. Int J Epidemiol., 41(4): 
968–76. pmid:22933645 PubMed/NCBI   
Ofori-Asenso & Garcia, D. (2016). Cardiovascular diseases in Ghana within the context of  
globalization. Cardiovascular Diagnosis & Therapy, 6(1), 67–77. 
doi:  10.3978/j.issn.2223-3652.2015.09.02. PMCID: PMC4731582 
Pachikian, B. D., Neyrinck, A. M., Deldicque, L., De Backer, F. C., Catry, E., Dewulf, E. M.,  
Sohet, F. M., Bindels, L. B., Everard, A., Francaux, M., Guiot, Y., Cani, P. 
D.,&Delzenne, N. M. (2010). Changes in intestinal bifidobacterial levels are associated 
with the inflammatory response in magnesium deficient mice. Journal of nutrition, 140, 
509-514. 
83 
 
Palmer, M., Adani, H.-O., Bergstrom, R., Jakobsson, S., Akerstrom, G., & Ljunghall, S. (1987). 
Survival and renal function in untreated hypercalcaemia: population - based cohort study 
with 14 years of follow - up. Lancet, 1, 59 - 62. 
Peacock, M. (2010). Calcium metabolism in health and disease. Clinical Journal of the American 
Society of Nephrology, 5 (1), 23-30. 
Peacock, J., Folsom, A., Arnett , D., Eckfeldt, J., & Szklo, M. (1999). Relationship of serum and 
dietary magnesium to incident hypertension: The atherosclerosis risk in communities 
(ARIC) study. Ann Epidemiol, 9, 159-165. 
Peer, N., Steyn, K., Bradshaw, D., Norman, R., Laubscher, R., Dennison, C. R., Levitt, N. S.,  
Nyo, M. T., Nel, J. H., Commerford, P. (2008). Determinants of target organ damage in 
black hypertensive patients attending primary health care services in Cape Town: the Hi-
Hi study. Am J Hypertension, 21(8): 896-902. 10.1038/ajh.2008.210.  
Peppes, V., Rammos, G., Manios, E., Koroboki, E., Rokas, S. & Zakopoulos, N. (2008).  
Correlation between myocardial enzyme serum levels and markers of inflammation with 
severity of coronary artery disease and Gensini score: A hospital-based, prospective study 
in Greek patients. Clin Interv Aging, 3(4), 699–710. 
Perticone, F., Ceravola, R., & Pujia, A. (2001). Prognostic significance of endothelial 
dysfunction in hypertensive patients. Circulation, 104, 191-196. 
Qu, X., Jin, F., Hao, Y., Li, H., Tang, T., Wang, H., Yan, W. & Dai, K. (2013). Magnesium and  
the Risk of Cardiovascular Events: A Meta-Analysis of Prospective Cohort Studies. PLoS 
One, 8(3): e57720. doi:  10.1371/journal.pone.0057720. 
84 
 
Rand, R. N. (1978). Multilayer film elements for clinical analysis: applications to representative  
           chemical determinations. Clinical Chemistry, 24(8), 1343-1350. 
Ravn, H., Korsholm, T., & Falk, E. (2001). Oral magnesium supplementation induces favorable 
antiatherogenic changes in ApoE-deficient mice. ArteriosclerThrombVascBiol, 21, 858-
862. 
Rayssiguier, Y., Mazur, A., & Durlach, J. (2001). Advances in magnesium research: nutrition  
and health. John Libbey and Co. Ltd. 
Reddy K. S., Yusuf, S. (1998). Emerging Epidemic of Cardiovascular Disease in Developing  
Countries. Circulation, 97, 596–601. [PubMed] 
Reid, I., Mason, B., & Horne, A. (2002). Effects of calcium supplementation on serum lipid 
concentrations in normal older women: a randomized controlled trial. Am J Med, 112(5), 
343-347. 
Resnick, L., Laragh, J., Sealey, J., & Alderman , M. (1983). Divalent cations in essential 
hypertension. Relations between ionized calcium, magnesium, and plasma renin activity. 
N Engl J Med, 309(15), 888 - 891. 
Reunanen, A., Knekt, P., Marniemi, J., Maki, J., Maatela, J., Aromaa, A. (1996). Serum calcium, 
magnesium, copper and zinc and risk of cardiovascular death. Eur J Clin Nutr., 50, 431–
437. 
Rivas, I., Sanvisens, A., Bolao, F., Fuster, D., Tor, J., Pujol, R., Torrens, M., Rey-Joly, C., Muga,  
R. (2013). Impact of medical comorbidity and risk of death in 680 patients with alcohol 
use disorders. Alcohol Clin Exp Res. 221–227.  
Romani, A.,  Marfella, C. & Scarpa, A. (1993). Regulation of magnesium uptake and release in  
85 
 
the heart and in isolated ventricular myocytes. Circulation Research, 72(6), 1139-1148. 
Romani, A., Marfella, C. & Scarpa, A. (2000). Regulation of cellular magnesium. Front Biosci, 
5, 720-734. 
Romani, A. M (2007). Regulation of magnesium homeostasis and transport in mammalian cells.  
Archives of biochemistry and biophysics, 458(1), 90-102. 
Romani, A. M. (2008). Magnesium homeostasis and alcohol consumption. Magnesium research,  
21(4), 197-204. 
Rosenthal, F., & Roy, S. (1972). Hypertension and hyperparathyroidism. BMJ, 4, 396 - 397. 
Ross, R. (1999). Atherosclerosis—an inflammatory disease. New England journal of medicine,  
340(2), 115-126. 
 
Rotter, I., Kosik-Bogacka, D., Dołegowska, B., Safranow, K., Karakiewicz, B., & Laszczynska,  
M. (2015). Relationship between serum magnesium concentration and metabolic and  
hormonal disorders in middle-aged and older men. Magnesium Research, 28(3), 99-107.  
Sabanayagam, C., & Shankar, A. (2011). Serum calcium levels and hypertension among US 
adults. J Clin Hypertens , 13(10), 716-721.  
Sakaguchi, Y., Fujii, N., Shoji, T., Hayashi, T., Rakugi, H., Iseki, K., Tsubakihara, Y., Isaka, Y.  
(2014). Magnesium modifies the cardiovascular mortality risk associated with 
hyperphosphatemia in patients undergoing hemodialysis: A cohort study. PLoS ONE, 
9(12), e116273. https://doi.org/10.1371/journal.pone.0116273 
Salah, K., Pinto, Y. M., Eurlings, L. W., Metra, M., Stienen, S., Lombardi, C., Tijssen, J. G.,  
Kok, W. E. (2015). Serum potassium decline during hospitalization for acute 
decompensated heart failure is a predictor of 6-month mortality, independent of N-
86 
 
terminal pro-B-type natriuretic peptide levels: An individual patient data analysis. Am 
Heart J., 170(3), 531-542.e1. doi: 10.1016/j.ahj.2015.06.003.  
Saltevo, J., Niskanen, L., Kautiainen, H., Teittinen, J., Oksa, H., Korpi-Hyövälti, E., Sundvall,  
J., Männistö, S., Peltonen, M., Mäntyselkä, P. &Vanhala, M. (2011). Serum calcium level 
is associated with metabolic syndrome in the general population: FIN-D2D study.Eur J 
Endocrinol, 165, 429-434. 
Sanuade, O. A., Anarfi, J. K., de-Graft Aikins, A., Koram, K. A. (2014). Patterns of  
Cardiovascular Disease Mortality in Ghana: A 5-year Review of Autopsy cases at Korle-
Bu Teaching Hospital. Ethnicity and disease, 24(1), 55 – 59. 
Sanuade O. A., Anarfi J. K., de-Graft Aikins, A., Koram, K. A. (2013). Patterns of  
Cardiovascular Disease Mortality in Ghana: A 5-year Review of Autopsy cases at Korle-
Bu Teaching Hospital. Unpublished work last accessed at 
http://paa2013.princeton.edu/papers/130316...12 December 2015.  
Saris, N., Mervaala, E., Karppanen, H., Khawaja, J., & Lewenstam, A. (2000). Magnesium. An 
update of physiological, clinical and analytical aspects. ClinChimActa, 294, 1-26. 
Saris, N. E. L., Mervaala, E., Karppanen, H., Khawaja, J. A., & Lewenstam, A. (2000).  
Magnesium: an update on physiological, clinical and analytical aspects. Clinica chimica 
acta, 294(1), 1-26. 
Scatena, M., Liaw, L., & Giachelli, C. M. (2007). Osteopontin: a multifunctional molecule  
regulating chronic inflammation and vascular disease. Arteriosclerosis, thrombosis, and 
vascular biology, 27(11), 2302-2309. 
Seedat, Y. K. (2007). Impact of poverty on hypertension and cardiovascular disease in sub- 
Saharan Africa. Cardiovasc J Afr, 18, 316-20 pmid: 17957321.  
87 
 
Seelig, M. S., & Rosanoff, A. (2003).The magnesium factor. Avery Publishers, New York, USA 
Shakhalili, Y., Murset, C., & Meirim, I. (2001). Calcium supplementation of chocolate: effect on 
cocoa butter digestibility and blood lipids in human. Am J Clin Nutr, 73(2), 246-252. 
Shechter, M. (2003). Does magnesium has a role in treatment of patients with coronary artery  
disease? American Journal of cardiovascular drugs, 3, 231-239 
Shechter, M,. Kaplinsky, E., & Rabinowitz, B. (1996). Review of clinical evidence - is there a  
role for supplemental magnesium in acute myocardial infarction in high-risk populations 
(patients ineligible for thrombolysis and the elderly)? Coronary Artery Disease, 7(5), 
352-358. 
Shechter, M & Shechter, A. (2013). The Role of Magnesium in the Cardiovascular system:  
Magnesium in human health and disease, Nutrition and Health. Springer Science and 
Business Media, New York, USA 
Shechter, M & Shechter, A. (2005).Magnesium and myocardial infarction. Clinical calcium, 11,  
111-115 
Shechter, M., Kaphisky E., & Rabinomitz, B. (1992).The rationale of mg supplementation in  
acute myocardial infarction.A review of the literature. Archive of internal medicine,152, 
2189-2196 
Shechter, M., Sharir, M., Labrador, M., Forrester, J., Silver, B., & BaireyMerz, C. (2000). Oral 
magnesium therapy improves endothelial function in patients with coronary artery 
disease. Circulation, 102, 2353-2358. 
Shils, M. E., & Shike, M. (Eds.). (2006). Modern nutrition in health and disease. Lippincott  
Williams & Wilkins. 
Shufelt, C. L., Bairey,  Merz, C.N., (2009). Contraceptive hormone use and cardiovascular  
88 
 
disease.  J Am Coll Cardiol. 53(3): 221-31. 
Smith, T. J. (2009). Magnesium supplements for menopausal hot flashes. Journal of clinical  
oncology, 27(7), 1151-1152 
Song, Y., Li, T., van Dam, R., Manson, J., & Hu, F. (2007). Magnesium intake and plasma 
concentrations of markers of systemic inflammation and endothelial dysfunction in 
women. Am J Clin Nutr, 85, 1068-1074. 
Song, Y., & Liu, S. (2012. Magnesium for cardiovascular health: time for intervention. The  
American Journal of Clinical Nutrition, 95(2), 269-270. 
Spayd. R, et al. (1978). Multilayer film elements for clinical analysis. Clin. Chem. 24, 1348-1350 
Speer, M.Y., Yang, H.Y., Brabb, T., Leaf, E., Look, A., Lin, W.L., Frutkin, A., Dichek, D. and  
           Giachelli, C.M., (2009). Smooth muscle cells give rise to osteochondrogenic precursors    
            and chondrocytes in calcifying arteries. Circulation research, 104(6), 733-741. 
Speich, M., Bousquet, B., & Nicolas, G. (1981). Reference values for ionized, complexed, and  
protein-bound plasma magnesium in men and women. Clinical Chemistry, 27(2), 246-
248. 
Spiegel, D. (2011). Magnesium in chronic kidney disease: Unanswered questions. BloodPurif, 
31, 172 - 176. 
Stasiukyniene, V. (2001). Blood plasma potassium, sodium and magnesium levels in chronic  
alcoholism during alcohol withdrawal. Medicina (Kaunas, Lithuania), 38(9), 892-895. 
Stasiukyniene, V. (2002). Blood plasma potassium, sodium and magnesium levels in chronic  
alcoholic patients during alcohol withdrawal. Medicina, 38(9), 892-895. 
89 
 
Sugimoto, T., Tobian, L., & Ganguli, M. (1988). High potassium diets protect against 
dysfunction of endothelial cells in stroke-prone spontaneously hypertensive rats. 
Hypertension, 11, 579-585. 
Suwaidi, J., Hamasaki, S., Higano, S., Nishimura, R., Holmes, D. J., & Lerman, A. (2000). 
Long-term follow-up of patients with mild coronary artery disease and endothelial 
dysfunction. Circulation, 101, 948-954. 
Swaminathan, R. (2003). Magnesium metabolism and its disorders. Clinical Biochemistry 
Review, 24(2), 47-66. 
Taddei, S., Mattei, P., Virdis, A., Sudano, I., Ghiadoni, L., & Salvetti, A. (1994). Effect of 
potassium on vasodilation to acetylcholine in essential hypertension. Hypertension, 23, 
485-490. 
Takaya, J., Higashino, H., & Kobayashi, Y. (2004). Intracellular magnesium and insulin  
resistance. Magnesium research, 17(2), 126-136. 
Tominaga, M., Eguchi, H., Manaka, H., Igarashi, K., Kato, T. A. K. E. O., & Sekikawa, A.  
(1999). Impaired glucose tolerance is a risk factor for cardiovascular disease, but not 
impaired fasting glucose. The Funagata Diabetes Study. Diabetes care, 22(6), 920-924. 
Torres, M., Ferreira, S. T., Carvalho, D., & Sanjuliana , A. (2011). Dietary calcium intake and its 
relationship with adiposity and metabolic profile in hypertensive patients. Nutrition, 
27(6), 666 - 671. 
Touitou, Y., Godard, J., & Ferment, O. (1987). Prevalence of magnesium and potassium 
deficiencies in the elderly. ClinChem, 33, 518-523. 
Trinder, P. (1969). Determination of glucose in blood using glucose oxidase ith an alternative  
90 
 
           oxygen receptor. Ann. Clin. Biochem. 6, 24. 
Vaskonen, T., Mervaala, E., Sumuvuori, V., Seppanen - Laakso, T., & Karppanen, H. (2002). 
Effects of calcium and plant sterols on serum lipids in obese Zucker rats on a low - fat 
diet. Br J Nutr, 87(3), 239 - 245. 
Vedanthan. R., & Fuster, V. (2008). Cardiovascular disease in Sub-Saharan Africa: a complex  
picture demanding a multifaceted response. Nat Clin Pract Cardiovasc Med, 5, 516-517 
doi: 10.1038/ncpcardio1281 pmid: 18607395.  
Volpe, M., Camargo, M., & Mueller, F. (1990). Relation of plasma renin to end organ damage 
and to protection of K+ feeding in stroke-prone hypertensive rats. Hypertension, 15, 318-
326. 
Weisinger, J. R., & Bellorín-Font, E. (1998). Magnesium and phosphorus. The Lancet,  
352(9125), 391-396. 
Wen, C. P., Cheng, T. Y. D., Tsai, S. P., Hsu, H. L., & Wang, S. L. (2005). Increased mortality  
risks of pre-diabetes (impaired fasting glucose) in Taiwan. Diabetes Care, 28(11), 2756-
2761. 
Whang, R. (1987). Magnesium deficiency: pathogenesis, prevalence, and clinical implications. 
Am J Med, 82, 24-29. 
Williams, E., Shah, S., & Ali, S. (2008). C-reactive protein, diastolic dysfunction, and risk of 
heart failure in patients with coronary disease: Heart and Soul study. Eur J Heart Fail., 
10, 63-69. 
Witteman, J., Grobbee, D., Derkx, F., Bouillon, R., de Bruijn, A., & Hofman, A. (1994). 
Reduction of blood pressure with oral magnesium supplementation in women with mild 
and moderate hypertension. Am J Clin Nutr, 60, 129-135. 
91 
 
Wiredu, E. K., &Nyame, P. K. (2001). Stroke-related mortality at Korle Bu Teaching Hospital,  
Accra, Ghana. East African Medical Journal, 78(4), 180-184 
Wolf, F. I., & Cittadini, A. (1999). Magnesium in cell proliferation and differentiation. Front  
Biosci, 4, d607-d617 
Wolf, F., Torsello, A., Fasanella, S., & Cittadini, A. (2003). Cell physiology of magnesium. Mol 
Aspects Med, 24, 11-26. 
Wong, G., Poon, W., Chan, M., Boet, R., Gin , T., & Ng, S. (2010). Plasma magnesium 
concrntrations and clinical outcomes in aneurysmal subarachnoid hemorrhage patients: 
post 65 hoc analysis of intravenous magnesium sulphate for aneurysmal subarachnoid 
hemorrhage trial. Stroke, 41(8), 1841 - 1844. 
WHO Regional Committee for Africa. (2015). Cardiovascular diseases in the African region:  
current situation and perspectives-report of the regional director 2005. (Accessed on 2015 
June 03). Available online: http://www.afro.who.int/rc55/documents/ 
afr_rc55_12_cardiovascular.pdf  
WHO Technical Report Series, Geneva, Switzerland, (1995). "Physical status: The use and  
interpretation of anthropometry" (PDF). World Health Organization. 854 (854): 1–452.  
World Health Organization (WHO). (2006). "BMI Classification". Global Database on Body  
Mass Index. World Health Organization.Retrieved July 27, 2015. 
World Health Organisation (WHO). (2016). Cardiovascular Diseases (CVDs), Factsheet  
(Accessed on 14 July 2016). Available online: http://www.who.int/mediacentre/ 
factsheets/fs317/en/ 
World Heart Federation (WHF). (2015). Global Cardiovascular disease Atlas: Sub-Saharan  
Africa (Accessed on 2015 June 03). Available online: http://www.medbox.org/ 
92 
 
cardiovascular-diseases/global-cardiovascular-disease-atlas-sub-saharan-africa/preview 
World Heart Federation (WHF). (2015). World Heart Federation Statement Provisional agenda  
item 12.6 The Global Strategy on Diet, Physical Activity and Health (Accessed on 2015 
April 12). Available online: http://webcache.googleusercontent.com/search?q= 
cache:fIfQXFstXXsJ:www.world-heart federation.org/fileadmin/user 
upload/documents/wha-nutrition-statement.pdf+&cd=1&hl=en&ct=clnk&gl=gh 
World Heart Federation (WHF), 2016. Last accessed at http://www.world-heart federation.org/ 
cardiovascular-health/cardiovascular-disease-riskfactors/...15 December 2016. 
World Health Organisation (WHO). (2015). Chronic Diseases: A vital Investment (Accessed on  
2015 April 03). Available online: http://www.who.int/chp/chronic_disease_report/ 
full_report.pdf 
World Health Organisation (WHO). (2015). Deaths from Cardiovascular diseases and diabetes.  
(Accessed on 2015 May 02). Available online: http://www.who.int/gho/ncd/mortality 
morbidity/cvd/en/ 
World Health Organization (WHO), Geneva (2005). Cardiovascular diseases in the African  
th
region: current situation and perspectives, 55  Session, Maputo Mozambique, August 
2005. 
World Health Organization (WHO). Geneva (2007). Prevention of cardiovascular disease.  
           Guidelines for assessment and management of cardiovascular risk.  World Health  
           Organization, Geneva, Switzerland, August 2007.  
World Health Organization (WHO), Geneva (2008). Causes of death, http://www.who.int/ 
healthinfo/ global_burden_disease/ cod_2008_sources_methods.pdf 
World Health Organisation (WHO). (2010).  The World Health Report on Global Health and  
Causes of Deaths 2010. Geneva: World Health Organization 2010. 
93 
 
World Health Organization. (2011). Global Atlas on Cardioasccular Disease Prevention and 
Control. World Health Organization in collaboration with the World Heart Federation 
and the World Stroke Organization. 3-18. 
World Life Expectancy (WLE). (2016). Accessed from http://www.worldlifeexpectancy.com/ 
ghana-coronary-heart-disease accessed 14 august 2016. 
Zarjou, A., Jeney, V., Arosio, P., Poli, M., Antal-Szalmás, P., Agarwal & Balla, J. (2009).  
Ferritin prevents calcification and osteoblastic differentiation of vascular smooth muscle 
cells. Journal of the American Society of Nephrology, 20(6), 1254-1263. 
Zemel, M. (1998). Nutritional and endocrine modulation of intracellular calcium: implications in 
obesity, insulin resistance and hypertension. Mol Cell Biochem, 188(1 - 2), 129 - 136. 
Zemel, M. (2002). Regulation of adiposity and obesity risk by dietary calcium: mechanisms and 
implications. J Am Coll Nutr, 21(2), 146S - 151S. 
Zhang, H. Y., Kluge, M., Timpl, R., Chu, M. L., & Ekblom, P. (1993). The extracellular matrix  
glycoproteins BM‐90 and tenascin are expressed in the mesenchyme at sites of 
endothelial‐mesenchymal conversion in the embryonic mouse heart. Differentiation, 
52(3), 211-220. 
Zheltova, A A., Kharitonova, M. V., Iezhitsa, I. N., & Spasov, A. A (2016). Magnesium  
deficiency and oxidative stress: an update.Biomedicine (Taipei); 6(4): 20. 
 
 
 
 
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APPENDIX I 
PARTICIPANT CONSENT INFORMATION SHEET 
I am Michael Amewonye of the Department of Medical Laboratory Sciences, School
 of Biomedical and Allied Health Sciences (SBAHS), College of Health Sciences of University 
of Ghana. I am embarking on a study entitle
Serum magnesium level and related biochemical parameters in cardiovascular diseases at the 
Korle-Bu Teaching Hospital. The purpose of this study is to determine whether serum 
magnesium level is implicated in the pathogenesis of cardiovascular diseases (CVD). The 
development of CVD is due to many factors and one of it may be due to the inadequacy of 
magnesium level. 
You will be asked few routine questions about your personal details and risk factors, etc. The 
benefits of the study, is to educate you on magnesium and its health benefits with respect to 
cardiovascular disease (CVD). It will be appreciated if you volunteer as a participant.  
Participation is entirely voluntary and strictly confidential
.You may choose to withdraw from the study whenever you wish. Participants of the study will 
undergo an overnight fast after which 5mls of blood will be withdrawn. Both procedures may 
involve slight discomfort. The amount of blood to be taken by phlebotomists and used for this 
research study will not exceed 5mls.  
You are assured of the strictest confidentiality of your personal information. This study will 
adhere to all applicable protocols and will maintain quality assurance in accordance with good 
laboratory practice. The blood samples collected will bear an identification code to ensure 
anonymity, confidentiality but afford ease of identification. There is the possibility that you 
might not benefit directly from participation. However, the information obtained and conclusions 
drawn will be applied in the adoption of relevant health policies as well as the appropriate care 
and management. You will incur no costs and you will also not be paid for participating in this 
study. However, you are entitled to know the outcome of the laboratory results and this will be 
well explained to you.  
My mobile contact numbers is 0244664025. You may call me for any further clarification. Thank 
you for the cooperation and anticipated compliance to the study requirements including signing 
of this consent information form and the participatory consent form. 
Signature/ Thump Print of Participant:…………………………….  Date: ……………………… 
Signature of Researcher:…………………………………………….Date: ……………………… 
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APPENDIX II 
INFORMED CONSENT FORM 
Research Title: Serum magnesium level in cardiovascular disease and apparently healthy 
individuals in Korle-Bu Teaching Hospital. 
 
I, ………………………………………………… …………….have been invited to take part in 
this research. I have been told of the purpose and procedure of this study which is to answer the 
questions raised about the effect of magnesium level on cardiovascular disease. I have agreed to 
give information about personal information such as my educational background, exposure to 
risk factors, etc.  I understand that I will not be compensated monetarily for participating in this 
study. I am aware of the risk, dangers and discomforts that might be associated with the pain of 
blood collection. The study team will try to reduce the chances of those risks happening by 
employing trained health professionals including phlebotomists. The arm will be sanitized before 
blood collection, and new sterile needles and gloves will be used for each participant. I promise 
to comply with the requirement of study. I have therefore given my consent accordingly. 
 
 
Signature/Thumbprint………………………………….. Date………………………………. 
 
 
  
 
 
 
 
 
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APPENDIX III 
QUESTIONNAIRE 
Participant’s ID (Code) ………………………..          Date…………………………………… 
 
A. SOCIO –DEMOGRAPHIC STATUS 
1. Age ………. (years) 18-29 [  ] 30-39 [  ] 40-49[  ]  50 -59 [  ] 60 and above [  ] 
2. Marital Status: Single [  ]  Married [  ] Divorced [  ] Widowed [  ] Separated [  ] 
3. Religion: Christian [  ] Muslim [  ] Others, please specify……………............................. 
4. Education: No formal education [  ] Basic education (middle/JHS) [  ] SHS/O –Level [  ]    
HND/Diploma Certificate [  ] Bachelor Degree [   ] Postgraduate Degree [   ] 
5. Employment Status: Employed [   ] Unemployed [   ] Retired [   ] Student [   ] 
6. Are you a vegetarian?  YES [   ]                  NO [   ] 
7 If no, what is your typical regular meal?   ……………………………………………….. 
8. Do you have any medical condition?  YES [   ]       NO [   ] 
9. If yes, please state the condition …………………………………………………………. 
10.  Are you on any medication?  YES [   ]   NO   [   ] 
11b. If yes, mention the main drugs…………………………………………………………… 
12a. Do you take other medication or herbal treatments?  YES [   ]     NO [   ] 
12b.  If yes, please state the name………………………………………………………………. 
 
B. LIFE STYLE BEHAVIOURS 
13a. Do you smoke?   YES [   ]     NO [   ] 
13b.  If yes, how often?  Daily [   ] Weekly [   ] Monthly [   ] Occasionally [   ] 
14.  Do you drink alcohol?  YES   [   ]      NO [   ] 
14b.  If yes, how often?  Daily [   ] Weekly [   ] Monthly [   ] Occasionally [   ] 
One servings of alcohol: 120ml of wine (½ medium glass of dry wine) 
285ml of beer (1/2 large beer bottle, one full mini Guinness) 
30ml (1 tot of spirit, whisky gin, akpeteshi and alcoholic bitters) 
60ml of (brandy, vermouth, aperitif) 
14c. On average, how many servings of alcohol do you take daily? .......................................... 
15 Do you exercise regularly? YES   [   ]      NO [   ].  If so, which type of exercise? 
…………………………… and how often do you exercise? .............................. per week 
16 Any other relevant comments 
………………………………………………………………………………………………
……………………………………………………………………………………………… 
 
Thank you! 
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APPENDIX IV 
DATA COLLECTION PROCEDURE 
 
At the consent of a participant following adequate briefing; 
 
1. Ask if a control participant has fasted for 8 to 12 hours and in case of a hospitalized 
subject, note the time of last meal and time of taking sample. 
 
2. Check and record the blood pressure (BP) of participants in duplicate 
 
3. If the systolic BP is within a range of 90 to 130mmHg and the diastolic BP is within the 
range 60 to 100mmHg, proceed to take weight and height measurement for the controls. 
 
4. If a consented control subject is discovered to be hypertensive, discontinue with the 
procedure and direct him/her to seek treatment. This helps in avoiding waste of the 
questionnaire and minimizes errors. 
 
5. However, if a CVD case is found to be hypertensive or not hypertensive, proceed to take 
weight and height measurement as in the case of the control subjects.  
 
6. Please estimate weight and height figures or values from the folder records of stroke 
patients. 
 
7. Administer the questionnaire, ensuring that each question is adequately filled in. 
 
8. Proceed to take the following samples using a 5ml syringe and dispensing as follows:  
a) 3ml of blood into the coded gel separator tube or chemistry tubes provided and 
marching the code on the administered questionnaire. 
b) 1ml of blood into the same coded sodium fluoride tubes 
 
9. oSort and transport the collected samples for processing, aliquoting and storage at -20 C 
 
10. 2+ 2+ +Perform the following serum analysis on each sample: Mg , Ca , K , PO4; Lipid 
profile; CK; FBG 
 
11. Compile the results and submit to the Researcher/Investigator 
 
 
 
 
 
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APPENDIX V 
OTHER DATA COLLECTION PROTOCOL 
 
INCLUSION CRITERIA 
Cases: 
 All clinically confirmed male and female patients with congestive cardiac failure (CCF), 
Ischaemic heart disease (IHD), hypertensive heart disease (HHD), stroke (cardiovascular 
accident) and peripheral artery disease (PAD) 
 
Controls:  
 Apparently healthy male and female individuals without knowing or having previous  record of 
hypertension, myocardial infarction or stroke, dyslipidaemia, diabetes, liver and kidney diseases 
or other metabolic syndromes. 
 
Common inclusion criteria: 
 All participants should be adults aging between 18 and 80 years 
 Both case and control participants are recruited from KBTH 
 All participants who have consented and signed the consent form. 
 
EXCLUSION CRITERIA 
All clinically confirmed male and female patients with congestive cardiac failure (CCF), 
ischaemic heart disease (IHD), hypertensive heart disease (HHD), stroke (cardiovascular 
accident) and peripheral artery disease (PAD). 
 
Any subject that failed to meet the inclusion criteria above is excluded from participating in the 
study. Any participant unwilling to sign the consent form will be excluded from participating in 
the study. 
 
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