Browsing by Author "Si, L."
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Item Annual transition probabilities of overweight and obesity in older adults: Evidence from World Health Organization Study on global AGEing and adult health(Social Science & Medicine, 2020-01-28) Biritwum, R.B.; Lartey, S.T.; Si, L.; Otahal, P.; de Graaff, B.; Boateng, G.O.; Minicuci, N.; Kowal, P.; Magnussen, C.G.; Palmer, A.J.Overweight/obesity is becoming increasingly prevalent in sub-Saharan Africa including Ghana. However, transition probabilities, an essential component to develop cost-effective measures for weight management is lacking in this population. We estimated annual transition probabilities between three body mass index (BMI) categories: normal weight (BMI ≥18.5 and <25.0 kg/m2), overweight (BMI ≥25.0 and <30.0 kg/m2), and obesity (BMI ≥30.0 kg/m2), among older adults aged ≥50 years in Ghana. Data were used from a nationally representative, multistage sample of 1496 (44.3% females) older adults in both Waves 1 (2007/8) and 2 (2014/ 15) of the Ghana WHO SAGE. A multistage Markov model was used to estimate annual transition probabilities. We further examined the impact of specific socio-economic factors on the transition probabilities. At baseline, 22.8% were overweight and 11.1% were obese. The annual transition probability was 4.0% (95% CI: 3.4%, 4.8%) from normal weight to overweight, 11.1% (95% CI: 9.5%, 13.0%) from overweight to normal weight and 4.9% (95% CI: 3.8%, 6.2%) from overweight to obesity. For obese individuals, the probability of remaining obese, transitioning to overweight and completely reverting to normal weight was 90.2% (95% CI: 87.7%, 92.3%), 9.2% (95% CI: 7.2%, 11.6%) and 0.6% (95% CI: 0.4%, 0.8%) respectively. Being female, aged 50–65 years, urban residence, having high education and high wealth were associated with increased probability of transitioning into the overweight or obese categories. Our findings highlight the difficulty in transitioning away from obesity, especially among females. The estimated transition probabilities will be essential in health economic simulation models to determine sustainable weight management interventionsItem Evaluation of the Association Between Health State Utilities and Obesity in Sub-Saharan Africa: Evidence From World Health Organization Study on Global AGEing and Adult Health Wave 2(Value in Health, 2019-06-13) Biritwum, R.B.; Lartey, S.T.; Si, L.; De Graaff, B.; Magnussen, C.G.; Ahmad, H.; Campbell, J.; Minicuci, N.; Kowal, P.; Palmer, A.J.Background: Obesity is a major public health challenge and its prevalence has increased across the age spectrum from 1980 to date in most parts of the world including sub-Saharan Africa. Studies that derive health state utilities (HSUs) stratified by weight status to support the conduct of economic evaluations and prioritization of cost-effective weight management interventions are lacking in sub-Saharan Africa. Objectives: To estimate age- and sex-specific HSUs for Ghana, along with HSUs by weight status. Associations between HSUs and overweight and obesity will be examined. Study Design: Cross-sectional survey of the Ghanaian population. Methods: Data were sourced from theWorld Health Organization Study of Global AGEing and Adult Health (WHO SAGE), 2014 to 2015. Using a “judgment-based mapping” method, responses to items from the World Health Organization Quality-of-Life (WHOQOL-100) used in the WHO SAGE were mapped to EQ-5D-5L profiles, and the Zimbabwe value set was applied to calculate HSUs. Poststratified sampling weights were applied to estimate mean HSUs, and a multivariable linear regression model was used to examine associations between HSUs and overweight or obesity. Results: Responses from 3966 adults aged 18 to 110 years were analyzed. The mean (95% confidence interval) HSU was 0.856 (95% CI: 0.850, 0.863) for the population, 0.866 (95% CI: 0.857, 0.875) for men, and 0.849 (95% CI: 0.841, 0.856) for women. Lower mean HSUs were observed for obese individuals and with older ages. Multivariable regression analysis showed that HSUs were negatively associated with obesity (20.024; 95% CI: 20.037, 20.011), female sex (20.011; 95% CI: 20.020, 20.003), and older age groups in the population. Conclusions: The study provides HSUs by sex, age, and body mass index (BMI) categories for the Ghanaian population and examines associations between HSU and high BMI. Obesity was negatively associated with health state utility in the population. These data can be used in future economic evaluations for Ghana and sub-Saharan African populations.Item Health service utilization and direct healthcare costs associated with obesity in older adult population in Ghana(Health Policy and Planning, 2020-03) Aikins, M.; Lartey, S.T.; de Graaff, B.; Magnussen, C.G.; Boateng, G.O.; Minicuci, N.; Kowal, P.; Si, L.; Palmer, A.J.Obesity is a major risk factor for many chronic diseases and disabilities, with severe implications on morbidity and mortality among older adults. With an increasing prevalence of obesity among older adults in Ghana, it has become necessary to develop cost-effective strategies for its management and prevention. However, developing such strategies is challenging as body mass index (BMI)-specific utilization and costs required for cost-effectiveness analysis are not available in this population. Therefore, this study examines the associations between health services utilization as well as direct healthcare costs and overweight (BMI ≥25.00 and <30.00 kg/m2) and obesity (BMI ≥30.00 kg/m2) among older adults in Ghana. Data were used from a nationally representative, multistage sample of 3350 people aged 50+ years from the World Health Organization’s Study on global AGEing and adult health (WHO-SAGE; 2014/15). Health service utilization was measured by the number of health facility visits over a 12-month period. Direct costs (2017 US dollars) included out-of-pocket payments and the National Health Insurance Scheme (NHIS) claims. Associations between utilization and BMI were examined using multivariable zero-inflated negative binomial regressions; and between costs and BMI using multivariable two-part regressions. Twenty-three percent were overweight and 13% were obese. Compared with normal-weight participants, overweight and obesity were associated with 75% and 159% more inpatient admissions, respectively. Obesity was also associated with 53% additional outpatient visits. One in five of the overweight and obese population had at least one chronic disease, and having chronic disease was associated with increased outpatient utilization. The average per person total costs for overweight was $78 and obesity was $132 compared with $35 for normal weight. The NHIS bore approximately 60% of the average total costs per person expended in 2014/15. Overweight and obese groups had significantly higher total direct healthcare costs burden of $121 million compared with $64 million for normal weight in the entire older adult Ghanaian population. Compared with normal weight, the total costs per person associated with overweight increased by 73% and more than doubled for obesity. Even though the total prevalence of overweight and obesity was about half of that of normal weight, the sum of their cost burden was almost doubled. Implementing weight reduction measures could reduce health service utilization and costs in this population.Item Rapidly increasing prevalence of overweight and obesity in older Ghanaian adults from 2007-2015: Evidence from WHO-SAGE Waves 1 & 2(Plos One, 2019-08-19) Biritwum, R.B.; Lartey, S.T.; Magnussen, C.G.; Si, L.; Boateng, G.O.; de Graaff, B.; Minicuci, N.; Kowal, P.; Blizzard, L.; Palmer, A.J.Background Studies on changes in the prevalence and determinants of obesity in older adults living in sub-Saharan Africa are scarce. We examined recent changes in obesity prevalence and associated factors for older adults in Ghana between 2007/08 and 2014/15. Methods Data on adults aged 50 years and older in Ghana were drawn from the WHO SAGE 2007/ 08 (Wave 1; n = 4158) and 2014/15 (Wave 2; n = 1663). The weighted prevalence of obesity, overweight, normal weight and underweight, and of high central adiposity were compared in 2007/08 and 2014/15. Multinomial and binomial logistic regressions were used to examine whether the determinants of weight status based on objectively measured body mass index and waist circumference changed between the two time periods. Results The prevalence of overweight (2007/08 = 19.6%, 95% CI: 18.0–21.4%; 2014/15 = 24.5%, 95% CI: 21.7–27.5%) and obesity (2007/08 = 10.2%, 95% CI: 8.9–11.7%; 2014/15 = 15.0%, 95% CI: 12.6–17.7%) was higher in 2014/15 than 2007/08 and more than half of the population had high central adiposity (2007/08 = 57.7%, 95% CI: 55.4–60.1%; 2014/15 = 66.9%, 95% CI: 63.7–70.0%) in both study periods. While the prevalence of overweight increased in both sexes, obesity prevalence was 16% lower in males and 55% higher in females comparing 2007/08 to 2014/15. Female sex, urban residence, and high household wealth were associated with higher odds of overweight/obesity and high central adiposity. Those aged 70+ years had lower odds of obesity in both study waves. In 2014/15, females who did not meet the recommended physical activity were more likely to be obese. Conclusion Over the 7-year period between the surveys, the prevalence of underweight decreased and overweight increased in both sexes, while obesity decreased in males but increased in females. The difference in obesity prevalence may point to differential impacts of past initiatives to reduce overweight and obesity, potential high-risk groups in Ghana, and the need to increase surveillance