Modifiable risk factors for Type 2 diabetes mellitus in a peri-urban community in South Africa

Summary Aims To investigate the prevalence of Type 2 diabetes mellitus (DM) and its risk factors in a working class peri-urban community in South Africa. Methods A cross-sectional descriptive study was conducted in 1996, where all persons aged 15 years and older, who were resident in randomly selected houses in Mamre, 55 km from the centre of Cape Town, were sampled. Subjects underwent a 75-g oral glucose tolerance test. Socio-demographic and anthropometric data were obtained and physical activity was assessed using a 7-day activity recall questionnaire. The 1985 WHO criteria were used to define diabetes. Results The response rate was 64.5% (n = 974). The participants comprised 56% women, 44% men, mean age 37.6 (range 15–86) years. The crude prevalence of Type 2 DM was 7.1% and impaired glucose tolerance (IGT) 8.0%. The age-adjusted prevalence of Type 2 DM was 10.8% (95% confidence interval (CI) 8.2–13.5%) and IGT 10.2% (95% CI 7.7–12.8%). Regression analysis indicated that age (risk ratio (RR) 7.40, 95% CI 3.45–15.86), waist circumference (RR 4.53, 95% CI 2.04–10.05), low total energy expenditure (RR 1.75, 95% CI 1.07–2.56) and family history of diabetes (RR 2.31, 95% CI 1.42–3.77) were independent risk factors for Type 2 DM, while sex, obesity and regular alcohol consumption were not. Conclusions This previously unstudied community has an intermediate prevalence on the international scale of Type 2 DM, which is linked to potentially modifiable risk factors.