The Prevalence and Identification of Risk Factors for NIDDM in Urban Africans in Cape Town, South Africa

OBJECTIVE: To determine the prevalence of NIDDM and associated risk factors in urban Africans in Cape Town, South Africa. RESEARCH DESIGN AND METHODS: With a three-stage, proportional, stratified, random cluster method, we sampled 1000 Africans, > 30 yr of age, living in African residential areas in Cape Town. We assessed glucose tolerance with a 75-g oral glucose tolerance test, according to World Health Organization criteria, and obtained anthropometric and demographic data. RESULTS: The response rate was 79%. The prevalence of NIDDM was 8.0% (confidence interval 5.8-10.3%), age-adjusted to world population figures and that of impaired glucose tolerance, 7.0% (confidence interval 4.9-9.1%). Multivariate analysis indicated that increased age (odds ratio 4.18), upper-segment fat distribution (odds ratio 2.94), proportion of life spent in an urban area (odds ratio 2.32), and obesity (odds ratio 2.31) were significant independent risk factors for NIDDM. In contrast, sex, family history, alcohol intake, and physical activity were not independent risk factors. Only increased age (odds ratio 4.06) was a significant risk factor for impaired glucose tolerance. CONCLUSIONS: The prevalence of NIDDM in urban Africans in Cape Town, South Africa, is moderately high, and considerably higher than previous reports from Africa. The association of NIDDM with urbanization has important implications in view of the large-scale urbanization occurring in southern Africa.