Prevalence and correlates of pre-diabetes in Sub-Saharan Africa using Demographic and Health Survey Data: a cross-sectional study

Objective The objective is to investigate the prevalence of pre-diabetes in Namibia and South Africa and to determine sociodemographic correlates of disease using population data. Design Cross-sectional study. Setting Demographic and Health Survey for emerging (Namibia) and established (South Africa) economies in Sub-Saharan Africa collected laboratory data that allowed determination of pre-diabetes status. Participants 3141 adults over age 18 from the 2013 Namibia survey, weighted to a population of 2176, and 4964 adults over age 18 from the 2016 South Africa survey, weighted to a population of 4627 had blood glucose/glycated haemoglobin (HbA1c) and diabetes information were included in the analysis. Outcome measures Pre-diabetes was defined as not being diagnosed with diabetes and having a blood sugar measurement of 100-125 mg/dL in Namibia or an HbA1c measurement of 5.7%-6.4%. Logistic models were run for each country separately, with pre-diabetes as the outcome and a series of sociodemographic variables (age, gender, urban/rural residence, number of children, employment status, wealth index, education level, and ethnicity (in South Africa) or religion (in Namibia)) entered as variables to investigate the independent relationship of each. Results The weighted prevalence of pre-diabetes was 18.7% in Namibia and 70.1% in South Africa. Rural residence was independently associated with higher odds of pre-diabetes in Namibia (1.47, 95% CI 1.05 to 2.06), while both younger age (0.98, 95% CI 0.97 to 0.99) and urban residence (0.80, 95% CI 0.66 to 0.99) were independently associated with odds of pre-diabetes in South Africa. Conclusions The prevalence of pre-diabetes was 18.7% in Namibia and 70.1% in South Africa. Correlates of pre-diabetes differed between the two countries with rural residents having higher odds of pre-diabetes in Namibia and urban residents with higher odds in South Africa. Aggressive interventions, including population level education and awareness programmes, and individual level education and lifestyle interventions that account for country-specific contextual factors are urgently needed to prevent progression to diabetes.