Background: Overweight and obesity are risk factors for many chronic diseases globally. However, the extent of the problem in low-income countries like Sub-Saharan Africa is unclear. We assessed the magnitude and disparity of both phenomena by place of residence, level of education and wealth quintile using cross-sectional data from 32 countries. Methods: Demographic and Health Survey (DHS) data collected in 32 Sub-Saharan African countries between January 2005 and December 2013 were used. A total of 250651 women (aged 15-49 years) were analyzed. Trained personnel using a standardized procedure measured body weight and height. Body mass index (BMI) was calculated by dividing body weight by height squared. Prevalence of overweight (25.0-29.9 kg/m2) and obesity (≥30.0 kg/m2) were estimated for each country. Analysis of the relationships of overweight and obesity with place of residence, education and wealth index were carried out using logistic regression. Results: The pooled prevalence of overweight for the region was 15.9 % (95 % CI, 15.7-16.0) with the lowest in Madagascar 5.6 % (95 % CI, 5.1-6.1) and the highest in Swaziland 27.7 % (95 % CI, 26.4-29.0). Similarly, the prevalence of obesity was also lowest in Madagascar 1.1 % (95 % CI, 0.9-1.4) and highest in Swaziland 23.0 (95 % CI, 21.8-24.2). The women in urban residence and those who were classified as rich, with respect to the quintile of the wealth index, had higher likelihood of overweight and obesity. In the pooled results, high education was significantly associated with overweight and obesity. Conclusions: The prevalence of overweight and obesity varied highly between the countries and wealth index (rich vs. poor) was found to be the strongest predictor in most of the countries. Interventions that will address the socio-cultural barriers to maintaining healthy body size can contribute to curbing the overweight and obesity epidemic in Africa.
Thirty-two nationally representative cross-sectional data from the most recent Demographic and Health survey (DHS) conducted between January 1, 2005, and December 31, 2013 in Sub-Saharan Africa were used. The DHS survey data were collected at about 5-year intervals across low and middle-income countries. DHS collect data on health and welfare by interviewing women of reproductive age (15–49 years), their children, and their households. In this analysis only women who had information on age and height were included. DHS surveys are available to investigators through the World Wide Web (http://www.dhsprogram.com). All 32 countries, DHS survey followed the same standard procedures. Detail descriptions of DHS sampling procedures, validation of questionnaire, and data collection methods are published elsewhere (http://www.dhsprogram.com). Briefly, the DHS used a stratified two-stage random sampling approach, consisting of a selection of census enumeration areas based on a probability, followed by a random selection of household from a complete listing of a household within the selected enumeration areas. In this study, all together 366885 women from 32 countries responded to the surveys with the response rates varying from 86.2 to 100.0 %. However, the present analysis is based on all women who had information on weight and height (N = 250651). Women granted written informed consent before interviewing them. Ethical approval was given by ICF International (Calverton, MD, USA) institutional review board and by individual review boards within every participating country. In all DHS survey, trained personnel measured the height and weight using a standardized procedure. Weight was measured using solar-powered scales with accuracy of 0.1 kg and height was measured using standardized measuring boards with accuracy to 0.1 cm. Body mass index (BMI) was calculated by dividing body weight (kg) by squared height (m2). Overweight and obesity were defined as recommended by World Health Organization [5]: overweight 25.0–29.9 kg/m2 and obesity ≥30.0 kg/m2. As the prevalence of obesity was low (<1 %) in some countries, the categories of overweight and obesity were combined together in the logistic regression analyses. Only the respondents who had information on BMI were included in the analyses. The participants’ place of residence was designated as rural and urban according to country specific definitions. The wealth index was calculated using easy-to-collect data on a household’s ownership of selected assets (e.g. televisions, bicycles, cars, materials used for housing construction and types of water access and sanitation facilities). The wealth index was then generated as a composite variable by demographic and health survey (DHS) staff using principal components analysis. Continuous scale of relative wealth was then categorized into five (poorest, poorer, middle, richer, and richest) according to the quintile of the sample. Wealth index was not available from the DHS data from Chad. Maternal education was assessed from self-report of the completed educational level (no education, primary, secondary, or higher). Sample weights were applied to the data to remove the bias due to unequal selection probabilities. Descriptive figures of the study participants are reported in percentages and the prevalence of overweight and obesity with their 95 % confidence intervals (CIs) are reported separately for each country. The pooled prevalence for the region was also estimated. Scatterplots were used to visualize the relationship between no education and overweight and obesity with the size of a marker relative to the number of outcome events to reflect their influence on the correlation. Analyses of the relationships between overweight and obesity and place of residence, education and wealth index were carried out. Odds ratios (ORs) and their 95 % confidence intervals (CIs) for overweight and obesity (<25.0 = 0, ≥ 25.0 = 1) were estimated in multivariate logistic regressions model including the place of residence (urban = 0, rural =1), maternal education (secondary or higher =0, no or primary education =1) and wealth index (richer or richest =0, poorest to middle =1). All the analyses were performed using the SPSS statistical software package version 21 and Stata version 13.
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