a1 MRC/Wits Rural Public Health and Health Transitions Research Unit (Agincourt), School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
a2 African Population and Health Research Centre (APHRC), PO Box 10787, 00100 Nairobi, Kenya
a3 Umeå Centre for Global Health Research, Department of Public Health and Clinical Medicine, Umeå University, Sweden
a4 INDEPTH Network, Accra, Ghana
a5 MRC Mineral Metabolism Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
a6 School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 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; post-pubertal participants had threefold higher odds v. pubertal participants; those with older mothers aged 50+ 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.
(Received May 31 2010)
(Accepted January 04 2011)
(Online publication February 28 2011)