Waist circumference percentiles of black South African children aged 10 - 14 years from different study sites

Background. Waist circumference (WC) is a useful predictor of cardiometabolic risk in children. Published data on WC percentiles of children from African countries are limited.Objectives. To describe age- and sex-specific Wpercentiles in black South African (SA) children from different study sites, and compare these percentiles with median WCpercentiles of African-American (AA) children.Methods. Secondary data on WC for 10 - 14-year-old black SA children (N=4 954; 2 406 boys and 2 548 girls) were extracted from the data sets of six studies. Smoothed WC percentile curves for boys and girls were constructed using the LMS method. The 50th percentile for age- and sex-specific WC measurements was compared across study sites and with AA counterparts.Results. Girls had higher WC values than boys from the 50th to 95th percentiles at all ages. The 50th WC percentiles of all groups of SA children combined were lower than those of AA children. When SA groups were considered separately, Western Cape children had median WC values similar to AA children, while rural Limpopo children had the lowest WC values. The 95th percentiles for Western Cape girls exceeded the adult cutoff point for metabolic syndrome (WC ≥80 cm) from age 11years.Conclusions. The differences in WC values for 10 - 14-year-old children across the six study sites highlight the need for nationally representative data to develop age-, sex- and ethnic-specific WC percentiles for black SA children. The results raise concerns about high WC among Western Cape girls

Development and tracking of body mass index from preschool age into adolescence in rural South African children: Ellisras Longitudinal Growth and Health Study.

The purpose of this observational prospective cohort study was to investigate the development and tracking of body mass index (BMI) of Ellisras rural children from preschool age into late adolescence from the Ellisras Longitudinal Growth and Health Study. Heights and weights of children were measured according to the standard procedures recommended by the International Society for the Advancement of Kinanthropometry twice a year from 1996 to 2003. In total, 2,225 children--550 preschool and 1,675 primary school--aged 3-10 years (birth cohorts 1993 to 1986) were enrolled at baseline in 1996 and followed through out the eight-year periodic surveys. In 2003, 1,771 children--489 preschool and 1,282 primary school--were still in the study. The prevalence of overweight was significantly higher among girls (range 1.6-15.5%) compared to boys (range 0.3-4.9%) from age 9.1 years to 14.9 years. The prevalence of thinness (severe, moderate, and mild) ranged from 7.1% to 53.7% for preschool children and from 8.0% to 47.6% for primary school children. Both preschool and primary school children showed a significant association between the first measurements of BMI and the subsequent measurement which ranged from B=0.2 (95% confidence interval [CI] 0.1-0.4) to B=0.8 (95% CI 0.6-0.9) for preschool and B=0.2 (95% CI 0.1-0.3) to B=0.7 (95% CI 0.6-0.8) for primary children. A significant tracking of BMI during 4-12 years of life was more consistent for preschool children (B=0.6 (95% CI 0.6-0.7) and for primary school children (B=0.6 (95% CI 0.5-0.6). Investigation of nutritional intake and physical activity patterns will shed light on how healthy these children are and their lifestyle.