Background: The 2016 Dar Es Salaam Call to Action on Diabetes and other NCDs advocates national multi-sectoral NCD strategies and action plans based on available data and information from countries of sub-Saharan Africa and beyond. We estimated trends, from 1980 to 2014, in age-standardised mean body mass index (BMI) and diabetes prevalence in these countries in order to assess the co-progression and assist policy formulation.
Methods: We pooled data from African and world-wide population-based studies which measured height, weight, and biomarkers to assess diabetes status in adults aged >18 years. A Bayesian hierarchical model was used to estimate trends, by sex, for 200 countries and territories including 53 countries across five African regions, (central, eastern, northern, southern and western) in mean BMI and diabetes prevalence (defined as either fasting plasma glucose of >7.0 mmol/L, history of diabetes diagnosis, or use of insulin or oral glucose control agents).
Results
African data came from 245 population-based surveys (1.2 million participants) for BMI and 76 surveys (182 000 participants) for diabetes prevalence estimates. Countries with the highest number of data sources for BMI were South Africa (n=17), Nigeria (n=15) and Egypt (n=13); and for diabetes estimates, Tanzania (n=8), Tunisia (n=7), Cameroon, Egypt and South Africa (all n=6).
The age-standardised mean BMI increased from 21.0 kg/m2 (95% credible interval: 20.3-21.7) to 23.0 kg/m2 (22.7-23.3) in men, and from 21.9 kg/m2 (21.3-22.5) to 24.9 kg/m2 (24.6-25.1) in women. The age-standardised prevalence of diabetes increased from 3.4% (1.5-6.3) to 8.5% (6.5-10.8) in men, and from 4.1% (2.0-7.5) to 8.9 % (6.9-11.2) in women.
Estimates in northern and southern regions were mostly higher than the global average; those in central, eastern and western regions were lower than global averages. A positive association (correlation coefficient ≃0.9) was observed between mean BMI and diabetes prevalence in both sexes in 1980 and 2014.
Conclusion: These estimates, based on limited data sources, confirm the rapidly increasing burden of diabetes in Africa. This rise is being driven, at least in part, by increasing adiposity, with regional variations in observed trends. African countries’ efforts to prevent and control diabetes and obesity should integrate the setting up of reliable monitoring systems, consistent with the WHO’s Global Monitoring System Framework.