Obesity: does it occur in African children in a rural community in South Africa?

BACKGROUND: Total body fatness and a centripetal fat patterning are recognized as risk indicators of cardiovascular disease in adulthood. In this study, the development of these risk factors in rural South African children during the preschool years and first years of formal schooling is explored.

METHOD: The initial cross-sectional data from the Ellisras Longitudinal Investigations in Rural Community Children Project, ongoing since 1996, were used, involving 684 boys and 652 girls, aged 3-10 years, in the Ellisras rural community. Overweight was measured using the body mass index (BMI) (kg/m2). Overfatness was based on the sum of the triceps and subscapular skinfold thicknesses. A centripetal fat patterning was measured by the sum of trunk skinfolds relative to limb skinfolds and the ratio of the subscapular to triceps skinfold. Further, the ratio of the subscapular to supraspinale skinfold was used as an indicator of lower body fat patterning. The 85th percentiles of the NHANES III were used as cutoff values for overweight, overfatness and a centripetal fat patterning.

RESULTS: At ages 7 and 8 years, mean BMI was statistically significantly higher in males compared to females (P < 0.05). The log transformed supraspinale skinfold thickness was larger in females compared to males at ages 4-7 years; the log transformed subscapular skinfold was larger in girls compared to boys aged 7-10 years. Less clear patterns were found for the extremity skinfolds and the skinfold ratios. Very few children (0-2.5% in males and 0-4.3% in females) had BMI values above the NHANES III 85th percentiles, indicating a very low prevalence of overweight children in the area. About 15% of the males showed overfatness at ages 3-4 years, while low prevalence was found at older ages.

CONCLUSION: Few Ellisras rural children had above normal values for BMI, indicating a low prevalence of obesity in this population. In the 3- and 4-year-old group more subjects were found to have excessive fat, as indicated by the sum of the triceps and subscapular skinfold thicknesses.