Predictors of adolescent weight status and central obesity in rural South Africa

Objective: To investigate predictors of adolescent obesity in rural South Africa.

Design: Cross-sectional study. Height, weight and waist circumference were measured using standard procedures. Overweight and obesity in adolescents aged 10-17 years were assessed using the International Obesity Taskforce cut-offs, while the WHO adult cut-offs were used for participants aged 18-20 years. Waist-to-height ratio of >0.5 defined central obesity in those at Tanner stages 3-5. Linear and logistic regression analysis was used to evaluate risk factors.

Setting: Agincourt sub-district, rural South Africa.

Subjects: Participants (n 1848) were aged 10-20 years.

Results: Combined overweight and obesity was higher in girls (15%) than boys (4%), as was central obesity (15% and 2%, respectively). With regard to overweight/obesity, fourfold higher odds were observed for girls and twofold higher odds were observed for participants from households with the highest socio-economic status (SES). The odds for overweight/obesity were 40% lower if the household head had not completed secondary level education. For central obesity, the odds increased 10% for each unit increase in age; girls had sevenfold higher odds v. boys; postpubertal participants had threefold higher odds v. pubertal participants; those with older mothers aged 501 years had twofold higher odds v. those whose mothers were aged 35-49 years; those in highest SES households had twofold higher odds v. those in lowest SES households.

Conclusions: In rural South Africa, adolescent females are most at risk of obesity which increases with age and appears to be associated with higher SES. To intervene effectively, it is essential to understand how household factors influence food choice, diet and exercise.