Determinants of obesity in an urban township of South Africa

02 Aug 2011

OBJECTIVE: To estimate the prevalence of overweight and obesity, and identify factors associated with Body Mass Index (BMI) and waist circumference (WC) among adults residing in an urban township in South Africa. DESIGN: Cross-sectional study. SETTING: Khayelitsha, a large black township located in Cape Town. SUBJECTS: 107 males and 530 females, aged ≥ 18 years. METHODS: The prevalence of overweight/obesity (BMI ³ 25 kg/m2) and abdominal obesity (WC ≥ 94 cm for men and ≥ 80 cm for women), and their relationship with factors previously found to increase the risk of obesity, such as age, gender, marital status, educational level, employment status, immigrant status from rural to urban, and physical activity level, were assessed using logistic regression analyses. RESULTS: The prevalence of obesity (BMI ³ 30 kg/m2) was 53.4% and 18.7%, and that of abdominal obesity was 71.5% and 23.4%, among women and men respectively. However, more women (21.3%) than men (11.2%) reported walking more than 45 minutes per day. Female gender and being married were associated with a high BMI and large WC. Recent migration was associated with a smaller WC. The level of physical activity was not associated with BMI or WC. CONCLUSIONS: These findings suggest that physical activity may play less of a role in obesity control, or that more than 45 minutes of physical activity per day is required to reduce the risk of obesity, especially in women. At least among South African women, obesity control focused on nutritional interventions may be more beneficial than increasing the intensity or duration of physical activity.