RC656.Ac 7 blthr C .l G330559 University of Ghana http://ugspace.ug.edu.gh INVESTIGATION OF THE POSSIBLE ROLE OF GOITROGENS IN THE DEVELOPMENT OF IODINE DEFICIENCY DISORDERS IN GHANA BY JULIANA ADJOAH ACQUAH A THESIS SUBMITTED TO THE DEPARTMENT OF NUTRITION AND FOOD SCIENCE, UNIVERSITY OF GHANA'IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF A MASTER OF PHILOSOPHY DEGREE IN NUTRITION DEPARTMENT OF NUTRITION AND FOOD SCIENCE UNIVERSITY OF GHANA, LEGON AUGUST, 1992 University of Ghana http://ugspace.ug.edu.gh i. D E C L A R A T I O N This project was conducted by me as presented under the supervision of Dr. E. Asibey-Berko of the Department of Nutrition and Food Science, University of Ghana. v jv i . A -.& fq fcd L..... JULIANA A. ACQUAH (STUDENT) • • . E. ASIBEY-BERKO (SUPERVISOR) University of Ghana http://ugspace.ug.edu.gh Dedicated to my husband, John Pwamang, Son, Wudior, and the family for their love and support both materially and spiritually. University of Ghana http://ugspace.ug.edu.gh A C K N O W L E G E M E N T S I wish to express my sincere gratitude to Dr. E. Asibey-Berko for his supervision of this project. His keen interest and valuable guidiance and assistance throughout this project made the work a success. Appreciation and gratitude go to Professor Sefa-Dedeh, Mrs Anna Lartey, Ms. Josephine Nketsia-Tabire, Mrs Agnes Simpson Budu, and Mr. David Bansah for their moral support and encouragement. Special thanks to Dr. J.K. Atta, a Lecturer at I.S.S.E.R, Dr. N.N.N. Nsowah- Nuamah, of Statistical Department and Mr. Albert Kwame Klevor for their assistance and advice in the statistical analysis of the data. I feel indebted to Mr. John Affel, Director of Education in Axim, and his family; the Blood Bank staff at Effua-Kwanta Hospital, Tokoradi, Sekoti and Axim Chiefs, Headteachers, 'Teachers and Pupils of the various schools visited who made collection of the data for this project a success. I am grateful to Dr. Amoah at Korle-Bu Teaching Hospital for his assistance. Special thanks goes to the technicians at the Nutrition and Food Science Department, Messrs E. Quansah, Kuma, J.A. Boney, D. Abugri, M. Da Maida the Librarian, Theophilus Kwame Agboli , the secretaries, Franklin P. Anku and Mr. D. Teye Korboeam for their help in diverse ways. Appreciation and gratitude also go to Mrs Margaret B. Quist-Therson at the Korle-Bu Teaching Hospital, Reference Laboratory for her help in the bacterial analysis of water-samples, Technicians at the Chemistry Department, Noguchi Memorial Institute For Medical Research, Standard Boards for their assistance in providing double distilled water, glasswares and chemicals. Special thanks and gratitude go to Miss Helen Attipoe of Environmental Protection Council and Mr. Vincent Attigah of Physics Department for typing my work so beautifully. Finally, special thanks goes to I.D.R.C. for sponsoring part of the project. iii.University of Ghana http://ugspace.ug.edu.gh A B S T R A C T The important role of iodine deficiency in the development of endemic goitre and cretinism is well established. However, it has been found that adequate iodine intake (75-300 fj.g/day) does not always eradicate goitre. Therefore, it is understandable that other environmental factors, known as goitrogens^present in die staple foods or drinking water contribute to the persistence of the disease. This paper reports on the possible role of goitrogens in the development of goitre in Axim (Western region, Ghana), Sekoti (Upper East region, Ghana) and Accra (Greater Accra region, Ghana; Examinations for thyroid size were carried out on 249 school children aged between ten and fourteen years inclusive in Sekoti, 220 in Axim, and 210 in Accra. With the target of analysing urine sample from at least 10% of those examined for goitre, urinary iodine and thiocyanate analysis were done on 43 pupils in Sekoti, 59 in Axim and 55 in Accra. Total goitre prevalence (visible and invisible) ranged from 56.2% in Sekoti, 20.5% in Accra and 17.3% in Axim. Mean urinary iodine levels in Sekoti was 22.93pg/dL, 46.9|Jg/dL in Axim and 20.5jJg/dL in Accra. The mean urinary thiocyanate was 3.30mg/dL, 1.13mg/dL and 1.84mg/dL res­ pectively in Axim, Accra and Sekoti. iv. University of Ghana http://ugspace.ug.edu.gh Based on goitre prevalence alone, Sekoti could be considered a severe ai'i! . ....endemic goitre area, while Accra Axim could be c1 nunltled as mild. However, the mean urinary iodine level in all the areas were highly in excess of the 5 ug/dl or less defined to be an indication of iodine deficiency. Moreover, goitrous pupils in all the areas were also excreting iodine levels (18.95 Mg I/dl, 47.8 j.jg l/dl and 21/42 j,g I/dl respectively in Sekoti, Axim and Accra) far higher than would be expected in people with dietary iodine deficiency. It may be concluded that the goitre endemia of the areas of study may be contributed to by goitrogens either in the food or water. The urinary iodine to thiocyanate ratio (I/SCN ratio) was used as an index to the exposure to dietary goitrogens, in this case, thiocyanate. This ratio was found to be almost statistically the same by analysis of variance in the three areas. The mean I/SCN ratio in Sekoti was 21. 4 jjg/mg; 42.2 |ig/ing in Ax ini and 29.1 iig/uig in Accra. Since the thiocyanate exposure is almost the same in the three areas, it could suggest that the high incidence of goitre seen in Sekoti may be contributed to by other goitrogens. Analyses of nutrient intakes based on the 24-hour dietary recall method showed that mean protein intakes were adequate and comparable to the Recommended Dietary Allowances, (RDA) in all the areas. How­ ever, the mean energy requirements in all three areas were not met. Axim had the lowest (64% of the RDA) while Accra and Sekoti met 74% and 73.7% respectively. The low energy intakes observed especially in Axim may explain the higher incidence of chronic malnutrition. 25% of the children in Axim were found to be stunted (less than 90% of mean height-for-age). Malnutrition was also found to be severe in University of Ghana http://ugspace.ug.edu.gh Sekoti in terms of wasting where 26,-5% of the children examined had weight-for-height values of less than 80% of standard. 17.2% of Sekoti children were also found to be chronically malnourished. Mean vitamin A intake was also found to be low in Sekoti (81% of the RDA) compared with Accra (1460% of the RDA) and Axim 1988% of RDA). Millet and sorghum contributed about 64% of the total daily caloric intakes according to the 24-hour recall. Thus the possible role of the goitrogenic effect of millet in the aetiology of the high incidence of goitre in the Upper East cannot be ruled out. A multiple logistic regression analysis revealed that about 90% of the variability in goitre prevalence could be attributed to a low iodine/high thiocyanate ratio (I/SCN ratio) chronic malnutri­ tion and vitamin A deficiency. Another possible contributing factor to the goitre seen in the areas of study may be attributed to polluted drinking water since most of the water samples collected in the study had a high bacterial and coliform counts as well as E. Coli. The findings of this study confirm what has been observed by Ingeenbleek, 1986 that protein energy malnutrition, hypovita- minosis A, and endemic goitre all of which were once considered distinct clinical entities resulting from specific alimentary deficiencies, might soon prove to be closely interrelated nutri­ tional disorders. It is recommended that plasma thyroid hormones and serum vitamin A levels should be measured to confirm the findings of this study. University of Ghana http://ugspace.ug.edu.gh V . T A B L E O F C O N T E N T S Declaration .... . Dedication .... . Acknowledgement ... . Abstract .... . Table of Contents List of Figures . List of Tables . CHAPTER ONE 1.1 CHAPTER TWO 2 . 1 2 . 2 2 .3 2 . 4 2 .5 2.6 2 .7 2.8 CHAPTER THREE 3.1 3 .2 3 . 3 3 .4 3 . 5 3 . 6 3 .7 : INTRODUCTION Aims and Objectives : LITERATURE REVIEW Definition of Iodine Deficiencey Disorders. Sources and Requirements of Iodine in Man. The Cycle of Iodine in Nature and the Iodine Content of Foods.......... .... ... Metabolism of Jodine .... .... ... The Role of Naturally-Occurring Goitrogens in the Development of Endemic Goitre ... Nutritional Status and Goitre .... ... Consequences of Iodine Deficiency Disorders Iodine Deficiency in Africa and Ghana ... MATERIALS AND METHODS Geographic Areas of Study The Subjects .... .... Epidemiological. Data .... Dietary Assessment .... Determination of Cyanide Content of Food Bacterial Analysis of Water . Statistical Analyses of Data .... . PAGE 1 11 iii iv v vi vii 1 2 4 4 4 5 8 12 27 28 31 36 36 37 38 42 42 42 42 University of Ghana http://ugspace.ug.edu.gh CHAPTER FOUR : RESULTS ................... 44 4.1 Epidemiological Data Goitre and Cretinism Prevalence .... .... .... .... 44 4.2 Anthropometric Data -Protein - Energy Malnu- trion Incidence .... .... .... .... 48 4.3 Biochemical Studies - Urinary Iodine, Thiocya- nate Ratios .... .*•• .... .... 57 4.4 Analysis of Nutrient Intakes .... .... 66 4.5 Food Habits .... .... .... .... 69 4.6 Cyanide Content of Selected Foods .. .... 73 4.7 Sources of Water .......... .... .... 76 4.8 Microbiological Studies of Water Samples.... 77 4.9 Data Analysis .... .... .... .... 82 CHAPTER FIVE : DISCUSSION 85 CHAPTER SIX : SUMMARY AND RECOMMENDATIONS 94 References .... .*•• ■•• • • • • ■ ■ * •. 99 Apendices .... .... .... .... .... 115 University of Ghana http://ugspace.ug.edu.gh VI. L I S T O F F I G U R E S FIGURES PAGE 1. The Iodine Cycle in Nature .... .... .... 6 2. The Pathogenesis of Iodine Deficiency .... .... 11 3. Antithyroid and Action Site .... .... .... 15 4. The Metabolic Disposal of Inorganic Cyanide .... 18 5. Thioglycoside Chemistry .... .... .... 19 6 . Linamarin and its Hydrolysis Products .... .... 20 7. Distribution of Endemic Goitre in Africa .... 32 8. Distribution of Endemic Goitre in Ghana .... 34 9. Comparison of Median Weight as a Function of Age in Males in Sekoti, Axim, and Accra .... .... 51 10. Comparison of Median Weight as a Function of Age in Females in Sekoti, Axim, and Accra .... .... 52 11. Comparison of Median Height as a Function of Age in Males in Sekoti, Axim and Accra .... .... 53 12. . Comparison of Median Height as a Function of Age in Females in Sekoti, Axim, and Accra .... .... 54 13. The Distribution of Urinary Iodine Excretion (jjg/dL) in Sekoti, Axim, and Accra .... .... .... 59 14. Comparison of Urinary Thiocyanate (SCN, mg/dL) in Sekoti, Axim and Accra .... .... .... .... 61 15. Comparison of the Distribution of the Urinary Iodine/ Thiocyanate Ratio (l/SCN,jjg/dL) in Sekoti, Axim, and Accra .... .... .... .... .... .... 62 16. The Relationship between the Urinary I/SCN Ratio and the Prevalence of Goitre .. .... .... .... 65 17. Comparison of the Mean Percentage RDA met for Calories, Protein, and Vitamin A in Sekoti, Axim, and Accra 67 University of Ghana http://ugspace.ug.edu.gh vii. L I S T O F T A B L E S TABLE PAGE 1. Naturally-Occurring agents Producing Goitrogenic and/of Antithyroid Effects .... .... .... .... 12 2. Incidence of Goitre in Africa .... .... .... 33 0 Percent Distribution of Goitre by Goitre Grade in the 44 Study Areas. 4. Percentage Distribution of Goitre by Goitre Grade in Males 45 5. Percentage Distribution of Goitre by Goitre Grade in Females 47 6 . Percentage Protein-Energy Malnutrition Among 10-14 Years School Children in the Study Areas (Washing) .... 48 7. Percentage Protein-Energy Malnutrition Among 10-14 Years School Children in the Study Areas (Stunting) .... 49 8. Mean Weight of Children 10-14 Years According to Age and Sex. .... .... .... .... ... .... 5 o 9. Mean Height of Children 10-14 Years According to Age 56 10. X.D.D. Severity and Need for Correction .... .... 57 11. Comparison Of the Urinary Iodine, Thiocyanate, and I/SCN Ratios in Sekoti, Axim, and Accra .... .... 58 12. Comparison of .Urinary Iodine, SCN, and I/SCN Ration Among Children with Goitre and those without Goitre from Sekoti, Axim, and Accra .... .... .... .... .... 63 13. Percentage Requirement met of Energy, Protein, and Vitamin A in 24-hour Dietary Recall .... .... .... 68 14. Percentage Requirement Met of Energy, Protein and Vitamin A Among Pupils with Goitre and those with Goitre ... 70 15. Percentage of Children Questioned who had Consumed the Principal Food Items at least once in the past week 72 16. Cyanide Content of Selected Foods .... .... 74 17. Definition of HCN Toxicity .... .... .... 74 18. Cyanide Content of Fruits and Vegetables in Sekoti .. 75 19. Percentage of Children Using the Following source of Water for Drinking .... .... .... .... 76 20. Bacterial Analysis of Water in Accra Samples .... 77 21. Bacterial Analysis of Water in Axim Samples .... 78 22. Bacterial Analysis of Water in Sekoti Samples .... 78 23. Microbiological Standards for Water (W.H.O. Reference) 79 24. Microbiological Standards for Water (Compiled by Korle-Bu Teaching Hospital Reference Laboratory) .... .... 80 25. Relationship of Goitre Prevalence with Urinary I/SCN Ratio, % RDA met for Vitamin A, and Chronic Malnutrition in Eleven Schools of the Study Areas .... .... .... 84 University of Ghana http://ugspace.ug.edu.gh 1. CHAPTER ONE 1.0 INTRODUCTION It is estimated that one billion people are exposed to the risk of goitre because of a deficiency of iodine, and most of them dwell in the tropical regions of the Third World (Hetzel, 19S8 ) . In Africa, endemic goitre is still a major public health problem affecting 227 (two hundred and twenty seven) million people. Owing to its benign appearance, endemic goitre ranks low in the hierarchy of acute and chronic diseases plaguing developing countries. Moreover, the full extent of its many complications, all of them deleterious to the well-being of the population as well as to the health budget of the country involved, is by no means fully appreciated. The most notable of these include: an increased rate of cretinism, whether myxedematous or neurological; severe post surgical complications such as hypoparathyroidism and laryngeal nerve paralysis; an association with impaired fertility and mental impairment of school children; and a higher prevalence of cancer (Benmiloud, 1982). It was considered until recently that iodine deficiency by itself would invariably result in the development of goitre and endemic cretinism. How­ ever, in the last few years, several groups of investigators have reported situations in which no goitre or endemic cretinism was evident despite severe dietary iodine deficiency (less than 25 ug/day) (Gilbert, 1984). These reports challenge the concept that iodine deficiency by itself invariably results in endemic goitre and cretinism. Therefore, it was logical to postulate the existence of other factors that, acting in conjunction with iodine deficiency, determine the development of these two pathological con­ ditions. In the presence of other environmental goitrogenic factors, iodine deficiency results in the highest incidence of endemic goitre. More than half of the population can be affected by the disease, with up to 10% University of Ghana http://ugspace.ug.edu.gh suffering from anomalies characteristic of endemic cretinism (Gaitan et al, 1978). The important role of iodine deficiency in the development of endemic goitre and cretinism is well established by several observations indicating that iodine supplementation consistently results in a marked decrease in the prevalence of endemic goitre and the disappearance of endemic cretinism. However, it has been found that adequate iodine intake (75-300 ug/day) does not always eradicate goitre as a prevalence rate of 6-40% persists in some areas (Gaitan, 1982). Therefore, it is understandable other environ­ mental factors are thought to contribute to the persistence of the disease. Under these circumstances, goitrogens in staple foods and water appear to be most important as environmental factors in the development of endemic goitre. Environmental goitrogens may, normally, be ineffective when low in concentration, but may become significant when the supply of iodine is low. In other situations, they may be sufficiently potent in themselves to cause goitre despite an abundance of iodine (Gaitan et al, 1978). In Ghana there has been no formal epidemiological survey to systema­ tically investigate the distribution, prevalence, and severity of goitre since the W.H.O. report (1958) and the National Food and Nutrition Survey (1961) reported that goitre is prevalent in the Northern and Upper Regions. Recently also undocumented incidences of goitre have been reported in the Volta Region, Kokofu in Ashanti and in some villages in the Akwapim hills belt (Asibey-Berko, 1990). There has also been no research to identify and assess the contribution of dietary goitrogens in the development of goitre in Ghana. 1.1 AIMS AND OBJECTIVES The aim of this project is to investigate the possible role of goitrogens in the development of goitre in Axim (Western region, Ghana), Sekoti (Upper East region, Ghana) and Accra (Greater Accra region, Ghana). University of Ghana http://ugspace.ug.edu.gh 3. Specific Objectives: (1) To conduct goitre surveys in some selected areas. (2) To determine the iodine nutritional status in these areas (ie. urinary iodine concentrations). (3) To study the nutrient intake of the people with special reference to Vitamin A, protein and energy. (4) To estimate urinary thiocyanate (SCN). (5) The food habits of the people with respect to consumption of vegetables, staples, seaweeds and fish. (6) To determine the total bacterial count, that is gram positive and E. coli in the sources of water. (7) To make a list of tables of foods containing hydrocyanic acid (HCN). University of Ghana http://ugspace.ug.edu.gh 2 . 1 CHAPTER TWO LITERATURE REVIVIEW DEFINITION OF IODINE DEFICIENCY DISORDERS Iodine is an essential micro-nutrient which is required for the synthesis of the hormone, thyroxine by the thyroid gland. The thyroid hormones have extensive effects throughout the body. They influence metabolic rate, protein synthesis, enzyme function, cellular transport, and other physiological processes. They are essential for normal growth and development and function of the brain and nervous' systems, and for maintenance of body heat and energy. When people do not have enough iodine, they cannot make enough thyroid hormones. This deficiency of iodine has several important health consequences that together are called "Iodine deficiency disorders1' or I.D.D. (Dunn, 1990). 2.2 Sources and Requirements of Iodine in Han The nutritional need of iodine depends on: (1) The rates of iodine excretion in the urine and feces, and (2) Individual "host" factors including growth, age, body-weight, sex, nutrition, reproductive functions, climate, disease, and the presence or not of goitrogens (Koutras, 1990). Inorganic iodine in the plasma (PII, plasma Inorganic Iodine) is one of the key factors controlling thyroid function. There is no renal homeostatic mechanism to keep the PII constant, so this varies with the iodine intake and the iodine excretion rates, urinary and fecal (Koutras, 1990, Wayne et al, 1964) When the PII falls below 0.08|jg/dl, iodine deficiency may occur (Koutras, 1990, Alexander et al, 1962). Iodine intake itself varies greatly from area to area, and even in the same area from individual to individual. Wayne et all (1964) have calculated that in order to ensure a safe PII level of O.OlOjjg/dl a dietary intake of 70)jg iodine daily is required on average. This would allow for 50|jg of urinary iodine and 20>jg for fecal excretion. Since the renal and fecal excretion rates may differ from person to person, individual requirements may University of Ghana http://ugspace.ug.edu.gh range from 40 to 120^g/day. Querido et al (1974) have defined an average urinary iodine excretion of 50)jg/day or 5)jg/dl as the minimum for adequate thyroid hormone synthesis (Koutras, 1990). The Food and Nutrition Board of U.S.A. National Research Council recommended an intake of 35)jg/day for babies up to 6 months, of age, 45|Jg/day for those 6-12 months, and 60-110)Jg/day for children 1-10 years of age, and 150)jg/day for older children and adults. The daily re­ quirement in adults is placed at about l-2)jg/kg of body weight. An iodine intake between "a minimum of 50jJg and a maximum of 1000/Jg/day" is considered safe (NAS, Food and Nutrition Board, 1971). An additional 25)Jg and 50^g are recommended during pregnancy and lactation respectively. These additional increases in pregnant and lactating women is due to the transfer of iodine to fetus or the milk. Furthermore, in pregnancy, the renal iodine clearance increases by 107% according to Aboul-Khair et al (1 9 6 4 ) . This leads to a fall in the PII, hence an increased prevalence of goitre during pregnancy (Koutras, 1990, Crooks et al 1964). 2.3 The Cycle of Iodine in Nature and The Iodine content of Foods Iodine intake depends on its concentrations in the food. This also depends on the iodine content of the soil where the food has been produced. In general, there are great variations in the iodine content of the soil. Iodine present in the original earth surface has been leached away by rain and carried to the oceans. However, from the oceans iodine evaporates, is concentrated in the rain, falls to the ground and gradually enriches the superficial soil. For this reason, old soils have a higher iodine content than newly formed ones. It also explains why proximity to the sea can affect iodine content of soil, plants and food. There is thus in nature an iodine cycle (Fig. I). Miyake and Tsunogai (1963) estimated that about 400,000 tons of iodine escape every year from the ocean surface. The iodine content of the ocean water averages 50jjg/l; whereas in the rain and river water it is 10 times less i.e. 5jug/l and it only 0.7jjg/l 5. University of Ghana http://ugspace.ug.edu.gh : The iodine cyc le in nature. Iod ine from Ihe ocoans (50 |.ig/i) evapora tes , is con ce n tra te d in the rain (5 ,ug/l), falls on the earth, and the r ivers c a n y back to the oceans (A dap ted from K outras 1986). University of Ghana http://ugspace.ug.edu.gh in the atmosphereic air (Matovinovic, 1983, Koutras, 1990). Heavy rain on slopy ground washes away the superficial iodine-rich soil layers, exposing the iodine - poor ones below them. Soil erosion is therefore accompanied by iodine deficiency. This happened also with the last glacial period, 8,000 to 18,000 years ago. Glaciation swept away the iodine rich superficial humic soil, and so areas subjected to intense glaciation are now afflicted with endemic goitre. The Iodine Content of Foods Iodine intake is based on the iodine content of the foods. Drinking water makes usually a small contribution, but its iodine concentration is an index of the iodine in locally produced foods, hence, its negative correlation with endemic goitre. In general, food contains widely different amounts of iodine, depending not only on the particular item, but also on the place where it has been produced. As a general rule, seafood contains the largest quantities, followed by terres­ trial animal food, whereas legumes and fruits contain very little. Recently, the contribution of adventitious sources of iodine is increasingly recognized. Several drugs contain large quantities of iodine, including, clioquinol, formerly widely used in developing countries for any diarrhea, and amiodarone, commonly used in some countries as an anti-arrhythmic. Furthermore, fish flour as chicken feed as well as iodoform as disinfectant may greatly in­ crease the iodine content of poultry and eggs. Iodate as dough-conditioner in bread and erythrosine as a colouring substance in candies and pills are other examples of adventitious sources of iodine. The iodine content of the food consumed is not the same with the iodine intake. Part of the iodine of the raw food may be lost during cooking. Harrison et al (1965) found that frying reduced the iodine content of fish by 20% and boiling University of Ghana http://ugspace.ug.edu.gh by 58%. Furthermore, from what is left, absorption is not always complete. Hence, the food consumed must contain more iodine than the minimum require­ ments listed above, so as to allow for these losses. 2.4 Metabolism of Iodine The normal human thyroid weighs 20-25g in adults. It contains 8-10mg of iodine, 95% of it bound to thyroglobulin. Some 45% and 3% of iodine in the diet absorbed from the intestine as inorganic iodide is normally taken up by the thyroid gland to produce thyroid hormones, thyroxine (T4) and tri-iodothy- ronine (T3) respectively. 42% occurs in the T3 and T4 precursors, mono and di-iodotyrosines (MIT and DIT). Thyroid structure and function are regulated by two inter-related systems. The first regulator is iodine itself and it controls both the thyroid hormone secretion and the reserves of iodine :Ln the form of iodotyrosines in thyro­ globulin. When the iodine supply is low, all functions of the thyroid gland are accelerated; at short or prolonged excessive iodine intake, all processes in the thyroid are slowed or modified. The second regulatory system, the pituitary thyroid stimulating hormone (TRH) of the hypothalamus, controls the thyroid function, serving to maintain the normal concentration of free thyroid hormone in the blood. Thyroid stimulating hormone is also known as thyrotropin or throtropic hormone (Taber's cyclo­ pedic Dictionary, 1973). Both control systems, the iodine and the TRH-TSH, regulate the intermediary metabolism of the thyroid cell, largely via the adeny1-cyclase-cyclic adenosine monophosphate. Under physiological condi­ tions, their effects are complementary (DeGroot et al, 1975). The production of thyroid hormone involves the following processes: 1. Iodide Transport: The transport of iodide from the plasma across the cell membrane is an active process against electrical and mass gradients. The normal concentra­ tion of iodide in thyroid cells is 30-40 times higher than in the serum. 8.University of Ghana http://ugspace.ug.edu.gh 9. 2. synthesis of Thyroid Hormones At the interface ot the cell and the colloid, a peroxidase is instrumental Ln oxidizing iodide (~l) into an "iodine - intermediate". It facilitates the formation of MIT and DIT by incorporating iodine into the tyrosyl/residues of thyroglobulin. These are called the processes of "organification". The subsequent oxidative coupling of iodotyrosines into 1'4 and T3 is also carried out by the same peroxidase that is the thyroidal peroxidase. 3. Secretion of Thyroid Hormones Thyroglobulin is engulfed by the cytoplasm of the thyroid cells and it undergoes proteolysis. The secretory phase ends by diffusion of the hormones into the capillaries via extracellular space (DeGroot et al 1975). Definition of Endemic and Spordic Goitre "Goitre" is defined as any enlargement of the thyroid gland, and as such it is a symptom and not a specific disease. "Non-toxic goitre is due to several causes (iodine deficiency, goitro­ genic substances, inborn error of thyroid hormone synthesis, and action, and auto immunity). But the pathogenesis is more or less the same. It is a pro­ cess aiming at keeping at normal levels the amount of thyroid hormones secreted, when this is threatened by any of the etiologic factors mentioned above. The compensatory hyperplasia (excessive increase in the number of normal cell in the tissue) leading to non-toxic goitre formation is in general initiated by an increased thyroid stimulating hormone (TSH) University of Ghana http://ugspace.ug.edu.gh secretion. If the compensation is adequate and the supply of thyroid hormones stays normal, the TSH level may fall back into the normal range, otherwise, it stays elevated (Koutras, 1990b). Non-toxic goitre may be sporadic i.e. affecting less than 10% of the population, or endemic, affecting more than 1 0%. The limit of 10% is of course arbitrary, but in any case when it is exceeded, an environmental cause, such as iodine deficiency or goitrogens is usually at play, hence the separate description of endemic goitre. According to Perez et al (1960), "A thyroid gland whose lateral lobes have a volume greater than the terminal phalanges of the thumb of the person examined, will be considered goitrous". Goitrogenesis Induced By Iodine Deficiency Endemic goitre is a direct consequence of the thyroid's adaptation to iodine deficiency. (fig 2) Dietary iodine deficiency causes depletion of thyroid iodine stores with reduced daily production of thyroid hormone (T4). A fall in serum T4 triggers the secretion of increased amounts of pituitary thyroid - stimulating hormone (TSH) which increases thyroid activity. The thyroid cells grow and multiply; the colloid of the follicle's empties; the vascularisation of the gland develops intensely and the size of the gland increases, even if a goitre as such is not detected clinically. Also there is increase in the activity of the iodide pump. The concentrating process of iodide by the thyroid gland is markedly enhanced through an in­ creased number of thyroid cells. Thyroid iodine uptake is increased so as: (1) to maintain a daily incorporation of about lOOug iodide into the gland; and (2) to adjust the renal excretion of iodine at the level of its dietary supply. (Koutras, 1990). University of Ghana http://ugspace.ug.edu.gh Fig 2: P A T H O G E N ESI S O F E N D E M IC G O I1 E R . SOURCE : Koutras, 1990. University of Ghana http://ugspace.ug.edu.gh 2.5 The Role of Naturally - Occurring Goitrogens In the Development of Endemic Goitre Goitre can arise from causes other than primary iodine deficiency, due to a variety of agents named as goitrogens (Gaitan, 1980). Goitrogens are antithyroid compounds that may be present in food or water and interfere with the formation of thyroid hormones by the thyroid gland and cause enlarged thyroid' (Goitre). Agents known to have goitrogenic and/or antithyroid effects on the thyroid of humans and other animal species are listed in Table 1. Environmental compounds may cause goitre by acting directly on the thyroid gland but also indirectly by altering its regulatory mechanisms and/or the peripheral metabolism and excretion of thyroid hormones. Agents Acting Directly on the Thyroid The various environmental goitrogenic and anti thyroid compounds, and their sites of action in the thyroid gland are shown in Figure 3. Goitrogens act in thyroid gland to interfere with the process of hormonal synthesis, but the mechanisms that induces the trophic changes leading to goitre formation is not yet well understood. Anti thyroid compounds can be divided into three catego­ ries according to the way they act on iodine metabolism in the thyroid (Gaitan, 1990). CLASS 1: The thiocyanates or thiocyanate - like compounds which appear primarily to inhibit the active concentrating mechanism of iodine, and their goitrogenic activity can be overcome by iodine administration. These ions have a molecular volume and charge similar to those of iodine. This is the reason they compete with iodine for transport in the follicular cell (Gaitan, 1990). 12. University of Ghana http://ugspace.ug.edu.gh 13. Table 1: Compounds Naturally - Occurring Agents Producing Goitrogenic and/or Antithyroid Effects Goitrogenic/Antithyroid Effects In Vivo In Vitro Human Animals Systems Sulfurated Organics Thiocyanate (SCN-) + Isothiocyanates NT L-5-Vinyl-2-Thio-oxa Zolidone (Goitrin) + Disulfides (R-S-S-R) NT Flavonoids (Polyphenols) Glycosides NT Aglycones NT C-ring fission metabolites NT (ie. Phloroglucinol, Phenolic acids) + + + + + + + + + + + (?) + + + Phenolics Phenol NT Catecol (1,2, dihydroxy- benzene) NT Resorcinol (1,3- dihydroxy benezene) + Hydroquinone (1,4 - dihydroxy benzene) NT m- dihydroxy acetophenones NT 2 - methylresorcinol NT 5 - methyresorcinol NT (orcinol) NT NT NT NT + + + + + 4 - methylcathecol NT NT University of Ghana http://ugspace.ug.edu.gh Compounds Goitrogenic/Antithyroid Effects In Vivo In Vitro Human Animals Systems Pyrogallol (1,2,3-tri hydroxy benzene) Phloroglucinol (1,2,3,- trihydroxy benezene Pyridines 3-hydroxy pyridine Dihydroxy pyridines Phtalate Esters and Metabolites Diisobutyl phtalate Dioctyl phtalate 0-phtalic acid m-phtalic acid 3.4 - dihydroxy benzoic acid (DH BA) 3,5, dihydroxy benzoic acid ■ Polycyclic Aromatic Hydrocarbons (PAH) 3.4 - benzpyrene (Rap) 3, methylcolanthrene (MCA) 7, 12-dimethyl-benzanthracene (DMBA) Inorganics Excess iodine Lithium NT + + NT + + NT NT + NT + + NT NT 0 NT NT 0 NT NT 0 NT NT 0 NT NT + NT NT + NT +(?) NT NT + NT NT + NT + + + + + + + = Active 0 = Inactive NT = non tested Source: Gaitan, 1990 University of Ghana http://ugspace.ug.edu.gh T h iocyana te I so th iocyana tes . Iodide T r a n s p o r t . G o i t r l n ’ F lavono ids Resorc tno ! & Phenol Ics DHBAs P y r id ln e s Ox ldat ion Orcjanic b in d in g and Coup I ing Iodide L it h iu m P r o te o l y s i s Release and Dehalogenat ion F i g ,3 N a t u r a l l y o c cu r r in g g o i t ro gen s and t h e i r s l t e ' o f a c t i o n In the t h y r o i d gland. DHBAs = d ih y d ro x ib e n z o ic acids; I =■ Iodide, MIT - m o n o io d o ty ro s in e ; Oi l = di l o d o ty ro s ln e ; T 3 = Lrl loc lo thyron Ine; T 4 = th y rox ine . SOURCE : Gaitan 1990 University of Ghana http://ugspace.ug.edu.gh 16. The isothiocyanates act on the thyroid mainly by their rapid conversion to thiocyanate. The naturally-occurring butyl, allyl, and methyl isothiocyanates do not inhibit the throidal peroxidase enzyme (Gaitan, 1986). However, isothio­ cyanates not only use the thiocyanate metabolic pathway but react also sponta­ neously with amino groups forming di-substituted thirourea - like antithyroid effect. Additive antithyroid effects of thiocyanate, isothiocyanate, and the thioglycoside "goitrin" occurs with combinations of these naturally - occurring goitrogens. CLASS II: The thiourea or thionamide - like goitrogens interfere with the processes of organification of iodine and coupling of iodotyrosines to form the active thyroid hormones, and their action usually cannot be antagonized by iodine. These goitrogens prevent the oxidation, of iodine by thyroid peroxidase (TPO) and impair covalent binding of iodine to thyroglobulin. In small amounts, they inhibit the formation of active thyroid hormones from iodotyrosine precursors. In larger quantities, formation of MIT and DIT is impaired. These types of compounds do not prevent transporl of iodine into the thyroid gland, and pharmacological doses would be required to suppress iodine uptake. The naturally-occurring thioglycoside L-5-Vinyl-2-thiooxazolidone, "goitrin" is representative of this category. Goitrin is unique in that it does not degrade like thioglycosides. Goitrin acts in vitro on the thyroidal peroxidase and 1251 organification, and in vivo exerts a thionamide - like effect (Gaitan, 1986). University of Ghana http://ugspace.ug.edu.gh Flavonoids, which also belong to this category, are polyhydroxyphenols with a (6-C3-C6 structure (Cody et al, 1986). Flavonoid glycosides possess intrinsic antithyroid activity which is increased by conversion to flavonoid aglycones by o-methylation in the b-ring and by middle ring fission to phoroglucinol, resorcinol and other phenolic acids (Gaitan, 1990) . CLASS III Agents in this group interfere with the processes of proteolysis and release of thyroid hormones. The most important representative of this group is iodine (Gaitan, 1986). An excess intake of iodine, arbitrarily defined as 2mg or more per day, inhibits the synthesis and release of thyroidal hormones and eventually produces "iodine goitre" and hypothyroidism. The recommneded dietary allowance for iodine is 150)jg/day for both adult males and females who are not pregnant or lactating. An additional 25jjg and 50pg are recommended during pregnancy and lactation respectively. Lithium has also been shown to belong to this category (Gaitan, 1990). Goitre has developed in some mental patients as a result of treatment with high levels of Lithium. Agents Acting Indirectly on the Thyroid The thyroid hormones are excreted into the intestine in both free and conjugated forms, along with small amounts of their de-ionated metabolites. Glucuronide conjugation occurs mainly in the liver by the action of a UDP - glucuronyl transferase and sulfate conjugation mainly in the kidney by the action of a sulfate transferase. However, under normal circumstances little T4 and T3 are excreted in conjugated form. University of Ghana http://ugspace.ug.edu.gh The polycyclic aromatic hydrocarbons (PAH), 3 - methylcholanthrene (MCA) and 3, 4 - benzpyrene (BaP), accelerate T4 metabolism and excretion of T4 - glucuronide, but there is also indication that MCA interferes directly with the process of hormonal synthesis in the thyroid gland (Gaitan, 1986). Flavonoids not only inhibit the thyroid peroxidase (TPO), but acting on iodothyronine, deiodinase enzymes, also the peripheral metabolism of thyroid hormones (Cody et al, 1986). Furthermore polymers of the fla- vonoid, phloretin, interact with TSH preventing its action at the follicular thyroid cell, thus, indicating that this class of compounds alters thyroid hormone economy in a complex manner (Gaitan, 1990). Examples of Foods which Contain The Various Classes of Goitrogens Sulfurated Organics Studies have shown that staple foods in some third world countries such as cassava, maize, bamboo shoots, sweet potatoes, lima beans, and some millets may contain cyanogenic glucosides (thiocyanate precursors) capable of liberating large quantities of cyanide by hydrolysis. After their ingestion, these glucosides can be readily converted to thiocyanate (SCN) by a widespread tissue enzyme (Ermans, et al, 1980). In the human liver, cyanide is metabolized by the enzyme rhodanase in the presence of thiosulphate into thiocyanate, which is a goitrogen (see Fig. 4). Fig 4: The Metabolic Disposal of Inorganic Cyanide Thiosulphate + Pyruvate \Sulfur transferase \ + CN ■V _ OSO3 *• + thiocyanate 18. Thiocyanate + pyruvate Source: Montgomery, 1973. University of Ghana http://ugspace.ug.edu.gh Thioglucosides undergo a loosen re-arrangement to form isothiocyanate derivatives and in some instances thiocyanate (Fig. 5). Therefore, the amount of thioyanate in the urine is a good indicator of the presence of thioglycosides in food. Source: Van Etten, 1973 Only under conditions of moderate to severe iodine deficiency is SCN a strong goitrogen. During the past 30 years, thiocyanates and isothiocyanates have been shown as the principal goitrogens in cruciferae family, genus Brassica (Van Etten et al, 1973). The potent anti thyroid compound "goitrin" an aglucone from the thioglycoside progoitrin, was isolated from yellow turnips and from Brassica seeds (Gaitan, 1990). Fig 5: Thioglycoside Chemistry ^ S - C 6 H u 05 R-(J----------- N-0-S02 0-K+ Thioglucosidase H70 R-C N- S II + Glucose + KHS04 Thioglucoside R-N=c=s R-C=N R-S-C=N ThiocyanateIsothiocyanate Nitrile + Sulfur The cyanogenic glucoside of cassava and lima beans is also known as Linamarin and considered as a beta glucoside of acetone cyanohydrin which is then split by hydroxynitrilelyase into HCN and acetone (Fig. 6). University of Ghana http://ugspace.ug.edu.gh Figure 6 : Linamarin and its hydrolysis products. CN Glucose - C-CN + H2O B-glucosidase s Glucose + HO - C - CH^ CH3 Acetone cyanohydrin Linamarin CN HO - C CH3 hydroxynitrile HCN + 0 = C-CH lyase 3 CH3 Acetone cyanohydrin Acetone Scource : Montgomery, 1973 Both enzymes are in the plant tissues and are released when the cells are broken. No free HCN is readily ever present in these plants and vegetables until the glycosides are broken. Lima beans seed of different varieties may release 10-30mg HCN per lOOg seed while fresh cassava releases 38mg per lOOg. Cassava is however processed reducing the cyanide content to l-6mg per lOOg in different preparations. Consumption of unfermented cassava is suspected to contribute to the goitre problem in Eastern Nigeria (Ekpechi, 1973), and myxedematous endemic cretinism (1-7%) in a population of 1.5-20 million people in the northern part of Idjwi Island and Ubanga, Zaire (Matovinovic, 1983). Glycosides occur in the inedible portions of the foods mentioned, with the exception of cassava and therefore do not pose much threat. However, with cassava, the glycosides occur in the edible portion (Van Etten et al 1973) . Another form of goitrogen is known as goitrin. Its anti-thyroid effect cannot be counteracted by dietary iodine. These are derived from (R) 2-hydroxy-3-butenyl-glycosinolate present in cabbage, cauliflower, brussels sprouts, broccoli, kale, kohlrabi, turnips, rutabaga, rapeseed, mustard and crambe. These vegetables were shown to be high in thiocyanate, isothiocyanate and goitrin (Van Etten, 1973). University of Ghana http://ugspace.ug.edu.gh Apart from the foods mentioned above, there have been several goitre endemias attributed to these sulfurated organics in foodstuffs (Delange et al, 1983). Two goitre endemias have been ascribed to the presence of these goitrogenic subs­ tances in milk. One was in Tasmania, where a seasonal variation in goitre prevalence in school children was noted in spite of adequate iodine intake, and in which an isothiocyanate, cheilorine, was suspected as the principal goitrogen (Clements, 1968). The other occurred in Finland, where goitrin present in cow's milk from the region of endemic goitre was considered as the causative factor. Rats fed for 1-2 years on milk produced in districts with endemic goitre developed thyroid glands almost twice as large as those in control rats given milk from non-goitrous districts (Gaitan, 1982). The concentration of 1,5, Vinyl-2-thio-oxazolidone (goitrin) in the range of 35-100)Jg/l in milk specimens from goitre districts, exceed the level necessary to explain the goitrogenic effect of this milk when fed to rats in long-term experiments. Thus, the authors concluded that goitrin might well be responsible, at least in part, for the goitre endemia in those areas of pinland. On the other hand, available data from the Tasmanian endemia failed to establish the goitrogenic properties of milk (Gaitan, 1982). In Idjwi Island (Kivu Lake) and the Ubangi area in Central Africa, as many as 60% of the population are affected by goitre. Studies have shown that cassava, a staple food in these areas, has definite anti thyroid effects in humans and experimental animals. Thus daily consumption of some types of cassava in the presence of severe iodine deficiency, is thought to be the causative factor of endemic goitre and cretinism in these areas of Zaire (Delange et al, 1971). University of Ghana http://ugspace.ug.edu.gh The Effect of Mineral Elements In The Incidence of Goitre Cobalt and also manganese, have been reported to be necessary for the synthesis )f the thyroid hormone in rats. The addition of physiological doses of colbat :o a diet which was not naturally high in iodine or cobalt did not affect the 7eight of the gland, but caused definite histological changes, including in increase in the height of the epithelial cells and a decrease in the size of :he follicles. It was concluded that the appearance of endemic disturbances of ihyroid gland function in people inhabiting biogeochemical provinces with a _ow iodine and a low cobalt content depend not only on the level of Iodine and of -.obalt, but also the ratio/these elements in the environment. Other workers .n the Soviet Union CKovalsky,1970) , have observed an inverse relationship >etween the cobalt levels in the foods, water, and soils in certain areas and he incidence of goitre in man and farm animals. A possible relationship etween these warrants investigation in other areas and further critical examina- ion of the suggestive cobalt iodine interaction in animals is desirable Hegsted et al, 1976). Fluoride: The role of fluoride in goitrogenesis is controversial in both experimental s well as epidemiological studies (Koutras, 1980). It has been suggested as n etiological factor in South Africa, Tanzania, and Kenya. However, fluorosis nd endemic goitre do not co-exist in Algeria or Nigeria. Calcium: The goitrogenic action of calcium, on the other hand, has been established nder experimental conditions. Although epidemiological data are conflicting, his problem can be reconciled if one assumes that the goitrogenic effect of igh calcium intake is unmasked only in presence of iodine deficiency. Some vidence of high calcium concentrations in water has been reported in Algeria, gypt, Sudan and Zambia (Osman and Fattah, 1981). University of Ghana http://ugspace.ug.edu.gh Disulfides: Small aliphatic disulfides, the major component of onion and garlic have sen shown to exert marked anti thyroid activity in the rat, and been incriminated y Abdou et al (1971) as a causative factor in Egypt. These foods, used argely in North African diets are consumed in both cooked and raw forms. Disulfides are also present in high concentration (0.3-0.5g/L) in aqueous Efluents from coal - conversion processes. Disulfides have also been identified 3 water contaminants in the United States in water supplying a Columbian district Lth endemic goitre (Gaitan, 1990). The most frequently isolated compounds l the United States are dimethyl, diethyl and diphenyl disulfides. Iodine: An excessive intake of iodine, arbitrarily defined as 2mg or more per day, lhibits proteolysis and release of thyroidal hormones and eventually produces .odide goitre" and hypothyroidism. Sustained ingestion of seaweeds (Kelp) _ch in iodine causes "endemic coast goitre" as described among natives in ikkaido, Japan (Suzuki, 1980). Suzuki reported that goitre prevalence in 8077 :hool children in the coastal districts of Hidaka and on the island Rishiri l s 9.0% and 2.6% respectively. In 3,400 school children in Sapporo, an inland iwn, it was only 1.3%. The population of seaweed fishermen of Hidaka (Hokkaido) id Rishiri consumed 10-50g of dry seaweed, mostly in soup while Kelp was not icluded in the diet of the people of Sapporo, a town far from the coast. The dine content of several varieties of Kelp was between 0.8 and 4.5g/kg of the ied plant, about 60% of which was in the form of iodide. A bowl of seaweed up contained 80-200mg iodide, but the consumption was on an intermittent basis, pending on the surplus of Kelp unsold at the market place. Goitre was more equent in girls at puberty, and it was also more common in some families, ggesting a possible goitrogenic influence of additional factors. 23.University of Ghana http://ugspace.ug.edu.gh Lithium: Studies in Venezuela documented higher lithium (Li+) concentration in the water supply of a high incidence endemic goitre locality than in nearby non-endemic communities. Experimental observations indicated that Li+ at those concentrations can be goitrogenic, but this effect is conditioned by dietary protein and iodine intake. It is accepted that Li+ is goitrogenic, as demonstrated by development of goitre in Lithium-treated manic patients. Li+ readily crosses the placenta with possible adverse effects on fetal thyroid function. Thus, an assessment of Li+ intake should be part of studies on environmental goitrogenesis (Gaitan, 1990). Flavonoids: Flavonoids are polyhydroxy phenolic compounds that usually exist in plants as complex glycoside polymers. Following ingestion by mammals, flavonoid glyco­ sides are hydrolyzed by intestinal microbial glycosidases to flavonoid aglycones which may be absorbed and undergo metabolism by mammalian tissues or be further metabolized by intestinal micro-organisms to undergo B-ring hydroxylation and middle ring fission with production of various metabolic compounds which include phenolic acid, phloroglucinol and gallic <*cid (Gaitan, 1988). Each metabolic step is characterized by marked increases in anti thyroid effects. For instance, flavonoid glycosides are 0 . 2 to 2 times as potent inhibitors of thyroid peroxidase (TPO) as propylthiouracil (PTU), while their corresponding aglycones are 0.5 to 14 times as potent, and the middle ring fission metabolite, phloroglucinol, 38 times more potent. - Flavonoids are important stable organic constituents of a wide variety of plants, including millet, sorghum, beans and groundnut etc. (Hulse, 1980). Epidemiological observations indicate that Pearl millet (Pennisetum americanum (L) Leeke) may be a factor contributing to the high incidence of goitre in rural areas of the semi-arid tropics, an ecological zone that almost circles the earth. 24.University of Ghana http://ugspace.ug.edu.gh Studies demonstrate that a diet comprised largely of millet is goitrogenic in the rat, and effect that is not overcome by high iodine intake. It suggests the activity of the type of goitrogen known as a goitrin. Heating and storage, akin to the manner in which millet is used as a food, increase the antithyroid activity of millet. Pennisetum millet is very rich in C-glycosyl flavones (C-GF). The C-GF glycosylvitexin, glycosyl rientin and vitexin, which constitute the largest proportion of the phenolic compounds in millet, all possess intrinsic antithyroid activity and appear, therefore, to be goitrogens in millet. Thiocyanate is also present in millet, and its antithyroid effects are additive to those of the C-GF (Gaitan, 1990). Thus, consumption of millet, together with iodine deficiency and various degrees of protein-calorie malnutrition, may contribute to the high incidence of goitre and attending morbidity in some areas of the semi-arid tropics. Water Borne Goitrogens Water borne goitrogens have also been known to cause goitre in parts of Latin America, Algeria, Sudan, and Egypt (Benmiloud, 1982). Polluted drinking water is common in these isolated areas. Bacteriological analyses done in these countries have revealed the presence of Clostridium perfringens and Escherichia Coli, both of which could be goitrogenic. They act either through production of myrosinase (Gaitan, 1980), which converts progoitrin into goitrin, or pro­ duction of a substance that has an effect similar to that of T.S.H. (Benmiloud, 1982). In bacteriological studies of some villages in Greece, the drinking water in villages with high prevalence of goitre was polluted with E. Coli and Coli-like substances significantly more often than water from non-goitrous localities (Malamos et al, 1971). A similar relationship had been demonstrated previously by Vought et al (1967) in Richmond Country, Virginia, U.S.A., where goitre exists despite adequate iodine supplementation. Vought et al (1974) also showed antithyroid activity in culture of E-Coli isolated from a polluted 25.University of Ghana http://ugspace.ug.edu.gh system in an area of high endemia. A class I-type anti thyroid activity reflected as reduced uptake of 131l by the rat thyroid was present in the 5x10 ̂to 10x104 molecular weight fraction of the cell-free extract of the E-Coli. More recent studies (Koutras, 1980, Gaitan, 1980) in endemic and non-endemic areas of Greece showed that concentrations of both E. Coli antibodies and Ig G were higher in the goitrous population than in the non-goitrous population of the endemic area, and that IgG concentrations were higher in the endemic area, where drinking water was subject to pollution, than in the non-endemic area, which had a non-polluted water supply. Previous epidemiological studies have shown a significant statistical corre­ lation (p< 0.005 to p< 0.0005) between goitre prevalence and rock types in watersheds supplying 37 localities in Western Colombia. This correlation accounted for 57% of the variation in goitre prevalence, and it was hypothesized that bacterial contamination of water supplies could be one factor involved in the remaining 43%. Therefore, bacteriological studies were performed to incorporate this variable into the statistical model in 34 of the 37 localities previously surveyed (Gaitan et al, 1980). Only two variables demonstrated significant relationships with goitre prevalence. The overall concentration of bacteria in the pipeline system (associated with increased goitre prevalance (p< 0.005) and K. pneumoniae in the water source (associated with decreased goitre prevalence, p< 0.001). A model fitted with the geological (p< 0.005) and bacteriological variables (p< 0.005) accounted for 80% of the variability in goitre prevalence. Phtalates are ubiquitous in their distribution have been frequently identi­ fied as water pollutants (Gaitan, 1986). Dibutyl and dioctyl have been repeatedly isolated from the goitrogenic well water supplying the high endemic goitre district of Candelaria Town in Western Columbia (Gaitan, 1983) . Phtalate esters were also found in water supplies from the coal - rich Appalachian goitre area of 26. University of Ghana http://ugspace.ug.edu.gh eastern Kentucky in the United States and from other goitre localities in Western Columbia (Gaitan, 1983). Commonly, phtalates result from industrial pollution or artificial contamination, but phtalates also occur naturally in plants, shale, crude oil, petroleum and as emission from coal - liquefaction plants (Gaitan, 1986). PAHs (Polycyclic Aromatic Hydrocarbons) have been found repeatedly in food, domestic water supplies, and in industrial and municipal waste effluents. They also occur naturally in coal, soils, ground water and surface water, and in their sediments and biota. One of the.mos.tpotent of the carcinogenic PAH compounds, 3,4, benzpyrene (BAP), is widely distributed and as in the case of other PAHs, is not efficiently removed by conventional water treatment processes (Gaitan, 1990). The PAH carcinogens, BAP and 3 - methylcolanthrene (MCA), accelerate T4, metabolism and excretion of T4 glucuronide, resulting in decreased serum T4 concentrations, activation of pituitary-thyrotropin-thyroid axis and eventually in goitre formation (Gaitan, 1990). 2.6 Nutritional Status and Goitre Nutrition may also play a role in goitrogenesis (i.e development of goitre), through protein-energy malnutrition and Vitamin A deficiency. These may have secondary effects on iodine nutritional status. Protein-energy malnutrition, occurring as marasmus, kwarshiorkor, marasmic- kwarshiorkor, or adult protein malnutrition, is commonly found in less developed countries with goitre endemias. Iodine malabsorption may be associated with protein-energy malnutrition (PEM) and thus contribute to endemic goitre (Ingenbleek and Beckers, 1973), particularly where iodine intake is limited. PEM may also interfere with iodide uptake by the thyroid (Gaitan et al, 1983), and with thyroglobulin formation (Ingenbleek and Devisscher, 1979). On the other hand, very severe P.E.M. in some areas with extremely low iodine intakes may impair the ability to develop goitre with a resultant mild prevalence rate for this condition (Delange, 1986). 27.University of Ghana http://ugspace.ug.edu.gh Another nutritional factor that may be involved in the goitrogenic action of cassava in humans is the protein-energy intake, since the endogenous conver­ sion of cyanide (HCN) into SCN, thiocyanate requires sulfur amino acids. Ex­ periments with pigs have indicated that protein deficiency protects against the anti thyroid action of cassava by reducing the quantity of SCN arising from HCN. It has also been shown experimentally that the presence of protein energy deficiency impaires the development of goitre due to a goitrogenic diet (Delange et al, 1982). Low blood retinol levels, an indicator of Vitamin A status, are correlated with higher goitre incidence (Ingenbleek et al, 1979). Studies in Senegal have shown that concomittant Vitamin A deficiency (ie. presence of Vitamin A deficiency as a secondary factor) increases the severity of iodine deficiency (Ingenbleek et al, 1986). The mechanism suggested for this is that decreased retinol could reduce thyroid hormone synthesis by defective glycosylation of thyroglobulin and its subsequent iodation. 2.7 Consequences of Iodine Deficiency Disorders Direct complications of endemic goitre are mechanical complications which are pressure symptoms. These are either from the trachea or from the esophagus. From the trachea, there is respiratory difficulty, progressing to dyspnoea (difficult or laboured breathing) and in rare cases to death from suffocation. X-rays show deviation of the trachea and narrowing of its lumen. From the esophagus, there may be difficulty in swallowing (Dunn, 1990, Koutras, 1990b). 28. Hypothyroidism - means that the body does not receive enough thyroid hormone. Hypothyroidism is detected by low levels of serum T4, relatively normal T3 and increased TSH Levels. Hypothyroidism produces sluggishness, University of Ghana http://ugspace.ug.edu.gh sleepiness, dry skin, cold intolerance, and constipation. In neonates, hypothyroidism results in mental retardation and impaired growth. It may contribute to endemic cretinism and other associated disorders (Dunn, 1990). Endemic Cretinism Endemic cretinism occurs only in areas of severe endemic goitre, and its pathogenesis is not well understood. However, the condition is defined by three major features according to the Pan American Health Organization. (1) Epidemiology: It is associated with endemic goitre and severe iodine deficiency. (2) Clinical Manifestations: These comprise mental deficiency together with either; (a) A predominant neurological syndrome including defects of hearing and speech, squint, and characteristic disorders of stance and gait of varying degrees or; (b) Predominant hypothyroidism and stunted growth. Although in some regions, one of the two types may predominate, in others a combination of the two syndromes will occur. (3) Prevention: In areas where adequate correction of iodine deficiency has been achieved, endemic cretinism has been prevented (Delange, 1990). There are three forms of endemic cretinism. These are: (a) Nervous or Neurological endemic cretinism (b) Mixed nervous - Myxedematous (c) Myxedematous cretinism Neurological Endemic Cretinism This is the commonest form of endemic cretinism. Its symptoms include principally impairment of intellectual function, of hearing and speech and of motoricity. Total deafness is accompanied by total mutism. 29. University of Ghana http://ugspace.ug.edu.gh The two main features of the motor disorder are proximal spasticity and regidity, both more marked in the lower extremities. The proximal spasticity is manifested by increased knee jerks and adductor jerks. Standing posture and gait are characterized by adductor thightness, partial flexion at hips and knees, occassionally wide-based; in severest cases, walking or even standing is impossible (Delange,1990) . The prevalence of goitre in these cretins is as high as in the non cretinous population of the area and they are clinically euthyroid. However, these individuals have higher serum TSH levels and lower levels of serum T4 and thyroidal uptake of radio-iodine than do non cretinous clinically euthyroid adults from the same endemic area. Myxedematous endemic Cretinism These cretins show less retardation than the neurological cretins and are often capable of performing simple manual tasks. All exhibit major clinical symptoms of longstanding hypothyroidism, dwarfism, myjtedema, dry skin, sparseness of hair and nails, retarded sexual development, and retarded maturation of body proportions. The prevalence of goitre in the myxedematous cretins is much lower than in the non cretinous population (Matovonic, 1983). (3) Mixed Neurological and Myxedematous This is characterized by dominant neurological disorders or dominant hypothyroidism in the same individual. Reproductive Failure Women in severely iodine deficient areas have more miscarriages, still births, and other problems of pregnancy and reproduction than do iodine - sufficient women. Continued miscarriages and fetal wastage decrease the fertility of a population and endanger the health of women (Dunn, 1990). University of Ghana http://ugspace.ug.edu.gh 31. Childhood Mortality Iodine deficiency kills children. Their defenses against infections and other nutritional problems are lower than those of children in iodine-sufficient areas. Socio-Economic Retardation Iodine deficiency also affects the socio-economic development of a community in two ways. First, the people are mentally slower and less vigorous. They are harder to educate and harder to motivate, and thus they are less pro­ ductive in their work. Scarce community resources may have to be diverted to support such persons. Secondly, in most of these areas, agriculture is the most important economic activity and domestic animals suffer from iodine deficiency in much the same way that people do. Thus domestic animals will be smaller and produce less meat, eggs and wool. They also have more abortions and are frequently sterile (Dunn et al, 1990). 2.8 IODINE DEFICIENCY IN AFRICA AMD GHANA A look at a map of Africa (Fig.7) shows that with the exception of a few Sahelian countries such as Mauritania and Niger and a few West African coastal countries such as Benin, Gabon and Togo, goitre endemia is present everywhere. The incidence of goitre varies among countries and regions within the same country (Table 2) severe endemias are found in Zaire and some of its neighbours, e.g. Angola, Chad, and Rwanda. Similarly, 20% (4 million) of the population of Algeria has a goitre incidence varying from 10-80%. Morocco has a smaller endemic area, but the incidence of goitre is quite high (Benmiloud et al, 1982). University of Ghana http://ugspace.ug.edu.gh 32. SOURCE : Benmiloud et al, 1982 University of Ghana http://ugspace.ug.edu.gh 33. Table 2: Incidence of Goitre in Africa Maximum Percentage Affected Countries < 90 Zaire, Angola, Chad, Uganda, Sudan < 80 Kenya, Sierra Leone, Algeria, Morocco, Tanzania, Mali, Upper Volta (Burkina Faso) < 60 Zambia, Egypt, Tunisia, Nigeria, Guinea < 50 Malagasy Republic, Central Africa Republic Senegal, Gambia < 40 Rwanda, Zimbabwe Source: Benmiloud et al, 1982 Although the areas involved are frequently found in the highlands or moun­ tains, this is not always the case. In Senegal, Egypt, Zaire, and Algeria goitrous areas can also be found at low altitudes. Although normally occurring inland, endemia can also be found on the seashore in Algeria, Tanzania, Sudan and Senegal. Iodine Deficiency in Ghana Figure 8 shows the endemic goitre areas in Ghana. In Ghana, endemic goitre has been reported from several places including Axim, (a coastal town), Brong- Ahafo, Mampong in Ashanti and the Upper Region (Baddoo, 1974). High incidences of goitre were reported from Sandema, Nandom and Bawku in the Upper Region. At a clinic in Zebilla, 25% of women in attendance had goitre. These goitres were reported to have started with the first pregnancy, receded between the pregnancies and recurred during subsequent pregnancies. In a 1961/62 National Nutrition Survey of Ghana, the nutrition of adults in the Northern and Upper Regions of Ghana was studied. In each of three towns - Binduri, Yarogo and Jirapa, goitre was found to be endemic. In each place, percentage of goitres were higher among women than men (National Food and Nutrition Board, Ghana 1961). University of Ghana http://ugspace.ug.edu.gh Fig. 8. MAP OF GHANA SHOWING THE M A JO R ROAD N E T W O R K AND T H E RAILWAY S Y S T E M 34.University of Ghana http://ugspace.ug.edu.gh Incidences of goitre have been reported recently in the Volta Region. Kokofu in Ashanti and more areas of the Northern Savannah of Ghana (Asibey Berko, 1990). 2.9 Summary Although the primodial role of iodine deficiency as environmental determinant in the development of endemic goitre and attending morbidity is firmly established, there is epidemiological and experimental evidence indicating that concomitant exposure to other naturally-occurring antithyroid agents, magnify the size of the goitre endemia and may affect as well as the clinical expression of the associated disorders. Furthermore, supplementation of iodine not always results in complete eradication of goitre leaving in some well defined instances, clusters or geographical "pockets" where the condition remains endemic. 35. University of Ghana http://ugspace.ug.edu.gh CHAPTER THREE MATERIALS AND METHODS 3.1 Geographic Areas of Study The research was conducted in three areas of Ghana. These were Axim in the South-Western, Sekoti in the Upper-Eastern and Accra, in the Greater Accra Region. These towns especially Axim and Sekoti were selected based on prior knowledge that goitre is prevelent in these areas (Asibey-Berko, 1990, 1991, Corraney, 1972). Axim (Appendix 1) is a coastal town and originally a fishing village. It lies close to the sea on flat and undulating sandy land at an altitude of 0-5ft above sea level with an annual average rainfall of 151.77mm. Axim being the district capital of the Nzema East area, is the principal administrative, educational and health centre for the whole district. According to the chief (personal communication), over 90% of the male population are engaged in fishing and faming, while the majority of the female population are involved in coconut oil production. The main produce food crop is cassava. Sekoti (Appendix II) is about 36km from the district and regional capital of Upper East, Bolgatanga on the Bolgatanga-Bawku road. It comprises seven villages, at an altitude of 820-960ft above sea level. The average annual rainfall is about 79.63mm. Their settlements consist of households which are scattered over a large area and widely separated from each other. The houses are built with earth consisting of round hut with a conical roof arranged in circles within an enclosing wall to form a compound household. Apart from the people, the household contains a poultry yard, a grain store and a piece of land where cattle and goats are kept for the night. The main occupation of the population is farming and rearing of cattles and goats, as well as guinea fowls and chickens. The crops grown in the area include rice, millet, guinea corn, beans and groundnuts. Sekoti has a Health Centre which is opened once a week to cater for the 36.University of Ghana http://ugspace.ug.edu.gh health needs of the people and those of the surrounding villages. Accra (Appendix III) is the country's political and administrative capital and also the headquarters of numerous institutions and organizations. It is the educational, commercial and entertainment centre for the country. It is a major industrial centre, it produces a wider range of medical facilities than any other town in the country. It is a major communication centre and offers more opportunities for employment than any other urban settlement in the country. Accra is at an altitude of about 50-250ft and has an average annual rainfall of 56.73mm. 3.2 The Subjects The subjects involved in the study were Primary/Junior Secondary School students aged between 10 and 14 years inclusive. School children were used because they congregate in one place and are easily accessible. They also are representative of the current state of iodine deficiency, and are a major priority group for prompt correction of iodine deficiency (Dunn, 1990). The age group was limited to 10-14 years because it has been found that the goitre is palpable at this time, when growth rate is very rapid. In each of the study areas, a minimum of 200 (two hundred) subjects were surveyed. Four schools were randomly selected and 50 pupils in each school selected using systematic random sampling (FAO, 1990) to take part in the goitre/cretinism survey and anthropometry. However, in Sekoti, there were only two schools, one primary and the other Primary/Junior Secondary school. The population for the 10-14 years group did not reach the two hundred needed for the goitre/cretinism survey. University of Ghana http://ugspace.ug.edu.gh Therefore, children from the community were also randomly selected to make up the number. A sub-sample of 14 pupils in each school were further systematically randomly sampled for urinary thiocyanate, urinary iodine,the "24-hour dietary recall" and the food habits of the students. 3.3 Epidemiological Data Goitre Survey: A recommended modification (Hetzel, 1988) of the technique suggested by Perez et al (1960) was used for the goitre survey. Physical Examination of the Subject The detection of goitre was done by palpation. The children were examined while standing with the head and neck in a vertical position. The thyroid area was examined and without delay the tips of the four fingers from both hands were used simultaneously to examine very gently the full extent of the lobes of the isthmus. The children were asked to relax the neck muscles by throwing their heads slightly backwards. Since the thyroid follows the movements of the larnyx during swallowing, the children were given a glass of water to swallow to differentiate the goitre from other neck masses. Classification of the Goitre Size (Appendix IV) Delange et al (1986) recommend the following classification of thyroid size: Size: Stage 0 : No goitre State IA : Goitre detectable by palpation and not visible even when the neck is fully extended. Thyroid lobes larger than ends of thumbs. Stage IB : Goitre palpable and visible only when the neck is fully extended. This stage also includes nodular glands, even if not goitrous. Stage 2 : Goitre visible with the neck in normal position, palpation is not needed for diagnosis. 38.University of Ghana http://ugspace.ug.edu.gh Stage 3 : Very large goitre that can be recognized at about 10 meters. Cretinism Survey A questionnaire (Appendix V ) was used to determine the cretinism rate. The presence of mental retardation were looked and inquired about. Defects of hearing, speech, presence of squint, disorders of stance and gait were recorded. Anthropometric Data (a) Weight The subject without any footwear and in light clothes was made to stand on the centre of the Seltzer bathroom scale, looking straight ahead with arms hanging on the sides. The weight was then taken in kilograms. (b) Height The height of the subjects were measured with a microtoise. The subjects, without shoes, were made to stand straight against a wall and the height measured with a microtoise in centimetres. Urinary Iodine Excretion Urinary iodine excretion was determined using the method of Sandell and Kolthoff (1937) as described by Karmarkar et al (1986). Casual urine samples were collected into 25-30mlsterile bottles and pre­ served with 0.1ml Acetic acid per 25ml urine. The urines were stored frozen as soon as possible and subjected to dry ashing for two hours at 600°c, i-n the presence of potassium carbonate. Iodide present in the ash was measured by Ceric arsenite system using Schimazu 120 spectrophotometer. (a) Water for Analysis Double distilled de-ionized water was collected from Noguchi Memorial Institute for Medical Research and de-ionized water from Chemistry Department of the University of Ghana to prepare any reagents needed in the urinary iodine assay. 39.University of Ghana http://ugspace.ug.edu.gh (b) Cleaning of Glassware All glassware used were washed and first boiled in 5N Cone. HNO^ for two hours and soaked overnight. The glassware were then first rinsed four times with tapwater, once with distilled water, twice with deionized water and finally with double distilled deionized water. Drying was carried out in air oven. Measurement of Concentration of Iodine In studies on iodine, some authors have used the iodine in jjg/creatinine in g ratio on spot samples and very rarely on 24-hour specimens. However, other studies have shown that the iodine status was much better reflected by pg iodine/dl concentration than by the iodine/creatinine ratio (Bourdoux, 1988). Therefore, it is suggested that iodine concentrations in spot sample expressed as microgram iodine per 100ml urine instead of the iodine/creatinine ratio should be used for assessing the iodine nutritional status (Dunn, 1990). While subjects will vary in the concentration of their urinary iodine depending upon how much liquid they have been drinking, this variation will tend to even out among samples from many subjects. For this reason, it is recommended that samples be obtained from at least 40 subjects to determine the mean concentra­ tion of urinary iodine in a given region (Dunn, 1990, Bourdoux, 1988). Thus in the study, iodine concentration was measured as microgram per 100ml urine. The concentration of each samples was calculated by using regression equation. In each batch of analysis, several standards were prepared including a quality control sample and the absorbances used for the regression equation. All analyses were done in duplicates. Ashing of Samples The dried urine samples in the test-tube were ashed at 600°C for two hours. During this period the furnace door was opened for 15 seconds at approximately 30 minutes intervals to renew the air in the furnace. 40.University of Ghana http://ugspace.ug.edu.gh Sample used for Quality Control The quality control sample was prepared from a pupil's urine in Accra. The concentration of iodine in the urine was measured using the method by Karmarkar (1986). The urine was then divided into small (0.5ml) quantities and stored frozen. The purpose of the Quality control was to ensure that reliable and acceptable results were obtained from the assays. The repeated analysis of the control should give results within the "acceptable limits of error". Percent Recovery Experiment A recovery experiment was done to check the accuracy of the method by Karmarkar (1986). In the experiment, a test sample was prepared by adding a standard solution of the analyte to an aliquot of a urine sample. A baseline sample was prepared by similarly adding solvent to a second aliquot of the urine sample. The two samples were then analyzed by the test method. The difference between the measured values of the two samples gave the amount recovered (Westgard, 1978). It is recommended that the volume of standard added to original sample should not be more than ten percent and that this be carried out by adding 0.1ml of standard to 1.0ml of a patient sample (Westgard, 1978). A. Sample Preparation for Percent Recovery Experiment A known concentration of standard Potassium Iodate was added to the aliquot of the same urine as follows: Sample (1) = baseline sample consisted of 1ml of urine +0.1ml water. (2) = 1ml of urine + 0.1ml ljjg^/dL (3) = 1ml of urine + 0.1ml dL (4) = 1ml of urine + 0.1ml SOpg^/dL B. Formulae for Calculating for Percent Recovery Experiment Cone. Added = Standard Cone, x ml Standard ml urine + ml Standard Cone. Recovered = Cone. Measured. - Cone. Measured,, ,(test) (baseline) 4 1. University of Ghana http://ugspace.ug.edu.gh 42. Recovery = Cone. Recovered x 100% Cone. Added The recovery of iodine was found to range from 83.3% to 95.59%. The sensitivity of the assay was found to ibe less than 1/jg/dL. Intra-assay coefficients of variation were from 0.19 to 1.5%. Classification of Severity of Iodine Deficiency The severity of iodine deficiency was classified as follows: Grade I : Mild iodine deficiency: There is an average of more than 5pg/dL in the urine. The thyroid hormone supply is adequate for normal physical and mental development. Grade II : Moderate iodine deficiency, the average urinary excretion is between 2.0-3.5)jg/dL. The secretion of thyroid hormones may not be adequate and these individuals are at risk of developing hypothyroidism but not overt cretinism. Grade III : Severe iodine deficiency: The average urinary iodine excretion is less than 2.0|jg/dL. The population is at serious risk of cretinism (Dunn, 1990, Matovinovic, 1973). Jrinary Thiocyanate (SCN) This was measured according to the procedure of Aldridge (1945). The concentration of urinary SCN was measured in mg/dL. Determinations were done in luplicates. )ietary Assessment (Appendix VI) The nutrient intake of the subjects were assessed using the "24-hour lietary recall". The subjects were asked to recall everything that they had saten within the last 24-hours including breakfast, lunch, dinner and foods :onsumed in between meals, both in and outside the home. The subjects were asked University of Ghana http://ugspace.ug.edu.gh to estimate the amount or size of food portions, using food portions obtainable from cooked vendors as reference. Samples of these foods were obtained from the place of purchase and weighed. The foods consumed were converted into the quantitative data of energy, protein and other nutrients using Food Composition Tables. The intakes were compared with FAO/WHO recommended daily intakes of nutrients (FAO/WHO, 1974, 1985). A questionnaire (Appendix VII) was also used for a listing of staples, vegetables, seaweeds, and fish eaten by the people. Samples of the staples and fruits eaten in the Upper East Region, in particular Sekoti, were collected into polythene bags, stored and used for goitrogen analyses - that is HCN. 3.5 Determination of Cyanide Content of Food The alkaline titration method by A.O.A.C. (1975) was used. About 20g of samples were used and determination done in duplicates. The cyanide content was expressed as mg HCN/Kg fresh weight. 3.6 Bacterial Analysis of Water 250ml of water was collected into sterile bottles from each source of drinking water at each locality for bacterial analysis. To reduce multiplication of bacteria, the samples were immediately placed on ice and refrigerated as soon as possible. The bacterial analyses were done at the Reference Laboratory at Korle Bu Teaching Hospital, Accra. 3.7 Statistical Analyses of Data 1. Anthropometric data were analysed using the National Centre for Health Statistics, U.S.A. recommended by W.H.O. for height and weight reference median value for age group 10-14 years. 43.University of Ghana http://ugspace.ug.edu.gh 44. Dietary intake were analysed by the use of the FAO Food Composition tables for Africa (1968) together with published information by Watson (1971) Ankrah and Dovlo (1973) and Eyeson and Ankrah (1975). Analysis of variance (ANOVA) was used to compare the means of the various variables in the three areas of study. Walker-Ducan Adaptive procedure was used to compare the means where ANOVA was found to be significant. The logistic multiple regression model was used to explore the possible relationship between the response variable (goitre) and the explanatory variables. This model was used because the outcome variable (goitre) is discrete taking on two or more possible values. That is the outcome variable is binary dichotomous. University of Ghana http://ugspace.ug.edu.gh CHAPTER FOUR R E S U L T S .1 Epidemiological Data - Goitre and Cretinism Prevalence The prevalences of goitre, and cretinism are compared in Tables 3 and 4. TABLE 3 : PERCENT DISTRIBUTION OF GOITRE BY GRADE IN THE STUDY AREAS (NUMBER OF SUBJECTS IN PARENTHESIS)_____________ 45. SURVEY AREA TOTAL Sekoti Axim Accra Total No. Examined 249 220 210 679 % 1A 16.9 (42) 13.2 (29) 15.7 (33) 15.3 (104) % IB 37.3 (93) 3.2 (7) 4.8 (10) 16.2 (110) % 2 2.0 (5) 0.9 (2) 0.0 (0) 1.0 (7) % 3 0.0 (0) 0.0 (0) 0.0 (0) 0.0 (0) % Visible goitre (grade 2-3) 2.0 (5) 0.9 (2) 0.0 (0) 1.0 (7) % Total goitre (grade 1 -3) 56.2 (140) 17.3 (38) 20.5 (43) 32.5 (221) % Normal (grade 0) 43.8 (109) 82.7 (182) 79.5 (167) 67.5 (458) Distance from the Sea. 610km 100m 200m Altitude Above Sea Level. 820-960ft 0-50ft 50-250ft University of Ghana http://ugspace.ug.edu.gh TABLE 4 : PERCENT DISTRIBUTION OF GOITRE BY GRADE AMONG MALES IN THE STUDY AREA (NUMBER OF PUPILS IN PARENTHESIS) SURVEY AREA TOTAL Sekoti Axim Accra Total No. Examined 159 113 99 371 % 1A 16.3 (26) 8.0 (9) 14.2 (16) 13.8 (51) % IB 32.1 (51) 0.9 (1) 1.0 (1) 14.3 (53) % 2 1.3 (2) 0.0 (0) 0.0 (0) 0.5 (2) % 3 0.0 (0) 0.0 (0) 0.0 (0) 0.0 (0) % Visible goitre (grade 2-3) 1.3 (2) 0.0 (0) 0.0 (0) 0.5 (2) % Total (grade 1 goitre -3) 49.7 (79) 8.8 (10) 17.2 (17) 28.6 (106) % Normal 50.3 (80) 91.4 (103) 82.8 (82) 71.4 (265) Goitre examinations were performed on 679 school children aged between ten and fourteen years inclusive. There were 371 males and 308 females. Overall goitre for both sexes was 32.5%. Goitre was found more prevalent in females (37.3%) :(table 5),'fchah'in males (28.6%) (table 4). There were marked differences in goitre prevalences among the school children from different areas (Chi-square trend p<0.001). The mean prevalence of goitre was 17.3% in Axim, 20.5% in Accra and 56.2% in Sekoti where 2.0% of the children population studied had visible goitre (grade 2). Among the schools within each area, total goitre prevelance ranged from 8.2% to 21.6 in Axim, 16.4 to 27.6% in Accra and 50.4 to 64.0% in Sekoti (Appendix IX). Endemic cretinism was not found in any of the areas studied. This may be probably due to the fact that parents will not normally send such children to the school. In fact in the community such persons are normally hidden (personal observations In Sekoti). (Table 3). University of Ghana http://ugspace.ug.edu.gh Tables 4 and 5 show the percentage distribution of goitre by goitre grade and sex ; > . Goitre grade 1A and IB are known as invisible goitre, while goitre grade 2-3 are collectively called visible goitres. Total goitre is defined as the sum of invisible and visible goitres. 47. TABLE 5 : PERCENT DISTRIBUTION OF GOITRE BY GRADE AMONG FEMALES IN THE STUDY AREA (NUMBER OF PUPILS IN PARENTHESIS) Total No. Examined SURVEY AREA TOTAL Sekoti Axim Accra 90 107 111 308 17.8 (16) 18.7 (20) 15.3 (17) 17.2 (53) 46.7 (42) 5.6 (6) 8.1 (9) 18.5 (57) 3.3 (3) 1.9 (2) 0.0 (0) 1.6 (5) O•o (0) 0.0 (0) 0.0 (0) 0.0 (0) 3.3 (3) 1.9 (2) 0.0 (0) 1.6 (5) 67.8 (61) 26.2 (28) 23.4 (26) 37.3 (115) 32.2 (29) 73.8 (79) 76.6 (85) 62.7 (193) % 1A % IB % 2 % 3 % Visible goitre (grade 2-3) % Total goitre (grade 1-3) % Normal University of Ghana http://ugspace.ug.edu.gh Most goitre were classified as goitre Grade 1 with IB predominating. In both Axim and Accra, goitre Grade 1A was more prevalent compared with goitre Grade IB in Sekoti. 4.2 Anthropometric Data - Protein Energy Malnutrition Incidence The nutritional status of the children assessed by means of body measurements of weights and heights compared with the U.S. National Centre for Health Statistics (NCHS) is shown in Table 6. Table 6: Percentage Protein-Energy Malnutrition Among 10-14yrs School Children in the Study Areas (Number of Children in Parenthesis) Weight For Height (Wasting) 48. Survey Area Sex No. Examined % [ Moderately wasted (60-80%) Median % Severely wasted <60% median Total wasting <80% median Sekoti Males 152 21.7 (33) 0 (0) 21.7 (33) Females 86 33.7 (29) 1.2 (1) 34.8 (30) Combined 238 26.1 (62) 0.4 (1) 26.5 (63) Axim Males 113 0 (0) 0 (0) 0 (0) Females 107 0 (0) 0 (0) 0 (0) Combined 220 0 (0) 0 (0) 0 (0) Males 90 1.1 (1) 0 (0) 1.1 (1) Accra Females 108 2.8 (3) 0 (0) 2.8 (3) Combined 198 2.0 (4) 0 (0) 2.0 (4) University of Ghana http://ugspace.ug.edu.gh Wasting, defined as a low weight-for-height (<-2SD from the reference median value or <80% Median value) is an indication for acute (rather than chronic) malnutrition. Wasting was most frequent in Sekoti where 26.5% of the children studied were total wasted, while 26.1% were severely wasted. In Accra, only 2.0% of the children were found total wasted while no wasting was found among Axim's school children. Among the schools within each area, percent total wasting ranged from 15.2 to 25.0% in males in Sekoti while total wasting in the females ranged from 23.2% to 37.7%. In Accra only 3 out of 22 boys or 13.6% in Osu were wasted. One out of 22 boys in Madina was wasted. While wasting was not found among children in Nima Primary/JSS or Mamprobi (Appendix X). 49. HEIGHT-FOR-AGE (STUNTING) TABLE 7 : PERCENTAGE PROTEIN-ENERGY MALNUTRITION AMONG 10-14 YEARS SCHOOL CHILDREN IN THE STUDY AREA (NUMBER OF CHILDREN IN PARENTHESIS) Survey Area Sex No Examined % Moderately Stunted 90-80% median value % Severely Stunted <80% Median value % Total Stuntec median <90% value Sekoti Males 152 19.7 (30) 0 (0) 19.7 (30) Females 86 9.3 (8) 3.5 (3) 12.8 (11) Combined 238 16.0 (38) 1.3 (3) 17.2 (41) Axim Males 113 23.0 (26) 6.2 (7) 29.2 (33) Females 107 17.8 (19) 3.7 (4) 21.5 (23) Combined 220 20.5 (45) 5.0 (11) 25.5 (56) Accra Males 90 3.3 (3) 2.2 (2) 5.6 (5) Females 108 1.8 (2) 0.0 (0) 1.8 (2) Combined 198 2.5 (5) 1.0 (2) 3.5 (7) Total Males 355 16.6 (59) 2.5 (9) 19.1 (68) Females 301 9.6 (29) 2.3 (7) 12.0 (36) Combined 656 13.4 (88) 2.4 (16) 15.8 (104) University of Ghana http://ugspace.ug.edu.gh Stunting due to chronic malnutrition (defined as <-2SD or <90% of median Height-for-age) was found highest among Axim School children, where 25.5% of the children studied were stunted. In Sekoti, 17.2% of the children were stunted compared with 3.5% in Accra. Among the schools within each area of study, Appendix XI shows that stunting ranged from 11.5 to 23.7% among males in Sekoti compared with 0-16.4% in females. In Axim, stunting ranged from 20.0 to 31.3% in males while 3.8 - 28.1% were found in females. In Accra, stunting in males ranged from 0- 13.6% as compared with 0-4.5% in females. The differences observed in degrees of stunting among males and females were highly significant (Chi-squared trend p<0.05). The development with age of weight and height in the three areas of study is shown in Tables 8 and 9 and figures 9-12. Weight in both females and males were systematically lower in Sekoti and Axim than in Accra (Fig. 9 and 10). Analysis of variance showed significant differences(p<0.05) in mean weight for age at all ages with the exception of the ten and eleven year olds in males. Mean height (Table 9 and Fig. 11 and 12) was also lower in Sekoti and Axim than in Accra in both males and females. All differences were also signifi­ cant at p<0.05 by Analysis of variance at ages 11-14 in males and all the ages in females. University of Ghana http://ugspace.ug.edu.gh 51. Fig 9. Comparison of Median Body Weight as a function of Age in Males in Sekoti, Axim, and Accra L E G E N D SEKOTI AXIM -------- A C C R A University of Ghana http://ugspace.ug.edu.gh M ED IA N BO DY W EI G H T (k g) AGES IN Y E A R S University of Ghana http://ugspace.ug.edu.gh 52. FigfiOl'i Comparison of Median Body Weight as of Age in Females in Sekoti, Axim, L E G E N D SEKOTI AXIM a function and Accra A C C R A University of Ghana http://ugspace.ug.edu.gh M ED IA N BO DY W EI G HT (k g) AGES IN YEARS University of Ghana http://ugspace.ug.edu.gh 53. Fig 11. Comparison of Median Body Height as a function of Age in Males in Sekoti, Axim, and Accra. L E G E N D SEKOTI AXIM A C C R A University of Ghana http://ugspace.ug.edu.gh M ED IA N BO DY H EI G H T (c m) AGES IN YEARS University of Ghana http://ugspace.ug.edu.gh 54. Fig 12. Comparison of Median Body Height as a function of Age in Females in Sekoti, Axim, and Accra. L E G E N D SEKOTI AXIM ACCRA University of Ghana http://ugspace.ug.edu.gh M ED IA N BO DY H E IG H T (c m) AGES IN Y E A R S University of Ghana http://ugspace.ug.edu.gh 55. Table 8: Mean Weight of Children 10-14years According to age and (sex separate) (Number of children in parenthesis) (a) Males AGE N (Years) SEKOTI AXIM ACCRA 10 26.85 + 3 .3 8(4 3) 27.2 - 4.02(12) 27.50 - 2.46(17) 11 28.29 - 4.21(29) 29.23 - 4.32(24) 29.71 - 4.90(21) 12 29.19 - 3.36(26) 31.73 - 4.64(28) 34.03 ~ 2.09(17) 13 31.17 - 4.83(24) 33.27 - 4.81(22) 38.06 - 8.16(18) 14 33.79 - 3.66(29) 38.13 - 6.46(27) 41.76 - 5.99(17) ■k +i.Mean Weight in Kg. - S.D. (b) Females AGE SEKOTI AXIM ACCRA (Years) 10 25.81 - 4.06(31) 28.95 - 4.18(23) 28.14 - 3.74(22) 11 24.90 - 4.00(15) 29.58 - 5.80(20) 32.75 - 4.76(18) 12 28.71 - 4.41(17) 33.91 - 4.80(22) 40.45 - 9.19(28) 13 33.33 - 7.21(12) 39.50 - 5.91(20) 43.64 - 7.06(18) 14 35.23 - 4.00(11) 39.61 - 4.91(22) 47.16 - 7.5(22) University of Ghana http://ugspace.ug.edu.gh 56. Table 9: Mean Height of Children 10-14 Years According to Age (sex separate) (Number of children in parenthesis) (a) Males AGE (Years) SEKOTI AXIM ACCRA 10 11 12 13 14 ■ X*136.36 ± 6.59(43) 139.65 - 6.78(29) 139.07 - 6.04(26) 146.87 - 8.43(24) 148.02 - 7.70(29) 132.58 - 6.26(12) 134.92 - 6.15(24) 138.39 - 6.72(28) 141.19 - 6.76(22) 148.00 - 8.50(27) 133.59 - 5.30(17) 137.95 - 5.49(21) 145.19 - 5.46(17) 50.29 - 9.35(18) 155.89 - 7.92(17) £i. Mean Height in cm - S.D (b) Females AGE SEKOTI AXIM ACCRA (YEARS) 10 134.48 - 8.24(31) 134.67 - 7.52(23) 133.77 - 6.01(22) 11 138.45 - 7.33(15) 134.39 - 6.98(20) 141.58 - 6.51(18) 12 144.92 - 5.83(17) 141.55 - 5.8(22) 149.61 - 4.74(28) 13 146.15 - 7.60(12) 147.31 - 7.22(20) 153.37 - 5.18(18) 14 152.49 - 6.42(11) 149.45 - 6.38(22) 158.39 - 3.88(22) University of Ghana http://ugspace.ug.edu.gh 4.3: Biochemical Studies - Urinary Iodine, Iodine-thiocyanate Ratios and thiocyanate Urinary iodine and thiocyanate excretion determinations were made on specimens from 157 pupils. 43 pupils in Sekoti, 59 in Axim and 55 in Accra. The severity of iodine deficiency would be classified as in Table 10. Table 10: I.D.D. Severity and the Need for Correction Stage goitre Clinical Hypo- thyrodism Features cretinism Typical goitre prevalence Mean urinary iodine (ug 1/dl) Neeid for correction 1 Mild + 0 0 10-30% 3.5-5.0 Important II + + Moderate + 0 20-50 2.0-3.5 Urgent III + + + Severe + + + + + 30-100 < 2.0 ' Clinical 0 = absent; +, + + and + + + = present with + + + being most severe. Source : Dunn, 1990 University of Ghana http://ugspace.ug.edu.gh TABLE 11 : COMPARISON OF THE URINARY IODINE, THIOCYANATE, AND I/SCN RATIO LEVELS IN SEKOTI, AXIM, AND ACCRA (MEAN ± S.E.M NUMBER OF CHILDREN ARE SHOWN IN PARENTHESIS) SEKOTI AXIM ACCRA (43) (59) (55) Total Goitre 56.2 17.3 20.5 Urinary Concen­ tration I (jjg/dL) 22.93 ± 2.13 46.93 ± 2.25 20.48 ± 0.76 SCN (mg/dL) 1.84 ± 0.16 3.30 ± 0.55 1.13 ± 0.12 . . . . a * Urinary ratio 21.36 ± 5.92 42.15 ± 9.89 29.06 ± 3.39 1/SCN (pg/mg) a* I/SCN ratio > 7 : Normal < 3 : Goitre Appearance < 2 : Goitre and Hyperendemia The differences between the urinary iodine concentrations in Axim, Accra and Sekoti were highly significant (p<0.001) by ANOVA. Axim had 2.3 times and 2.0 times higher urinary iodine concentration than Accra and Sekoti respectively. The distribution of urinary iodine concentrations is shown in Fig. 13. The mean urinary iodine in Sekoti was 22.93 ± 2.13)jg/dL, a level far higher than would be expected in a place with dietary iodine deficiency. In Accra, the mean jrinary iodine level was 20.48 ± 0.76 with a range of 6.35 - 28.89jJg/dL. No pupils were found below 5jJg/dL or excretion level indicating iodine deficiency. University of Ghana http://ugspace.ug.edu.gh 59. Fig 13. The distribution of Urinary iodine excretion (jjg/dL) in Sekoti, Axim, and Accra. L E G E N D ACCRA A X IM SEKOTI University of Ghana http://ugspace.ug.edu.gh Iodine (jjg/dL) University of Ghana http://ugspace.ug.edu.gh In Axim, the mean urinary excretion was 46.92 ± 2.25jJg/dL. The range of values were 14-84/jg/dL. No persons were also found to be below 5)Jg/dL. Among the schools within each area (Apprendix XII), it was observed that the differences in iodine concentrations were not statistically significant. The urinary SCN in Axim was 1.8 and 2.9 times higher than in Sekoti and Accra (See Fig.14). All differences for the urinary SCN were highly significant at p<0.001 by ANOVA. Accra had the lowest SCN with a mean of 1.13 ± 0.12, followed by Sekoti 1.84 ± 0.16 and Axim 3.30 ± 0.55mg/dL. Despite the high SCN excretion in Axim, and because of its high urinary iodine excretions, the I/SCN ratio was also high with a mean of 42.15 ± 9.89. In Accra, the mean I/SCN ratio was 29.06 ± 3.92, followed by Sekoti 21.36 ± 5.92. Although there was a progressive decrease in I/SCN ratio in the areas, these ratios were not statistically significant (p>0.05 by ANOVA). The distribution of the urinary iodine/thiocyanate ratio is shown in Fig.15. In Axim, 6.78% of the children were found to be below I/SCN of 3, the point where goitre develops as a result of dietary goitrogens, thiocyanate, compared with 11.65% in Sekoti and no pupils for Accra. Table 12 compares the mean urinary iodine, SCN and I/SCN ratios among pupils with goitre and those without goitre in each area. The result for the urinary iodine showed no significantly different from each other in Axim schools. However, in Sekoti, the mean difference between goitre and no goitre pupils was highly significant at p<0.001, while those in Accra were also significant at p<0.01. Appendix XIII compares the urinary iodine excretion among children with goitre and those without goitre in the various schools. 60.University of Ghana http://ugspace.ug.edu.gh 61. Fig 14. Comparison of Urinary Thiocyanate (mg/dL) in iixim, Sekoti and Accra. University of Ghana http://ugspace.ug.edu.gh M EA N C O N C E N TR A TI O N (m g/ dL ) A REA University of Ghana http://ugspace.ug.edu.gh 62. Fig 15. Comparison of Urinary I/SCN Ratio (]jg/mg) in Accra, Axim, and Sekoti. L E G E N D 7 Z l V. * •' ACCRA AXIM SEKOTI University of Ghana http://ugspace.ug.edu.gh Pe rc en t I/SCN Ratio (yg/mg) University of Ghana http://ugspace.ug.edu.gh X 1-9 a>u> University of Ghana http://ugspace.ug.edu.gh In all the areas, the mean I/SCN ratios among pupils with goitre and those without goitre, were not significantly different from each other. The SCN excretion in Sekoti and Axim was not significantly different from each other. However, in Accra those with goitre and without goitre, the SCN excretion was statistically different (p<0.01). Fig. 16 shows the association between the urinary I/SCN ratio and the prevalence of goitre in the three areas of study. It is shown that the increase in prevalence of goitre is inversely correlated to the progressive decrease of the urinary I/SCN ratio (r = -0.75 p<0.01) used as an index of the balance between the dietary supplies of iodine and thiocyanate, goitrogens. 64. University of Ghana http://ugspace.ug.edu.gh 65. Fig 16 The Relationship between the Urinary I/SCN Ratio and the prevalence of Goitre. L E G E N D % i % Total Goitre Mean I /SCN Ratio, University of Ghana http://ugspace.ug.edu.gh G O IT R E University of Ghana http://ugspace.ug.edu.gh 4.4 Analysis of Nutrients Intake The nutrient intakes of protein, energy and Vitamin A of one hundred and forty-two (142) pupils were assessed by the 24-hour dietary recall method. The percentage Recommended Dietary Allowance ^RDA) met for each individual was calculated using the FAO/WHO recommended nutrient intakes (1974, 1985) for age and sex. The net protein utilization (NPU) for protein in a mixed diet was taken as 70% (FAO/WHO, 1985). Table 13-14 and Fig. 17 show the mean nutrient intake of the subjects aged 10-14 years in comparison with FAO/WHO, 1985 recommended intakes. For sample calculation of Energy and protein requirement, see Appendix XX. Energy require­ ment in all the areas studied were not met. Accra and Sekoti met 74.00 ± 2.58% and 73.71 ± 2.43% respectively compared with Axim which only met 63.97 ± 3.55%. The mean difference of energy among the areas was highly significant (p<0.001 by ANOVA). However, between Sekoti and Accra, the percentage requirement met for energy was not statistically significant (p<0.05). Mean protein intakes for all the areas were above the RDA. Accra met 123.88 ± 6.46%, Sekoti 119.00 ± 7.71% and Axim 109.87 ± 4.58%. The differences observed in the areas for protein were significant at (p<0.05). Mean Vitamin A (Fig. 17) intakes were not satisfied by the children in Sekoti. The overall percentage requirement met was 80.86 ± 13.54% in Sekoti compared with 1460.44 ± 227.87% in Accra and 1988.68 ± 252.36% in Axim. The males in Sekoti however, met 107.89% of the Vitamin A requirement while females satisfied only 55.52%. 66. University of Ghana http://ugspace.ug.edu.gh 67. Fig 17 : Comparison of the Mean percentage Recommended Dietary Allowance (RDA) Met for Calories, Protein, and Vitamin A in Sekoti, Axim, an