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

The sensitivity of waist-to-height ratio in identifying children with high blood pressure.

We determined the sensitivity of waist-to-height ratio (WHtR) as a marker for high blood pressure in children aged nine to 15 years (n = 1 131), from schools in the North West province, South Africa. Anthropometric and blood pressure measurements were taken. The sensitivity and specificity of the WHtR to identify children with high blood pressure were evaluated. At a cut-off value of 0.5, 7.9% of the girls and 3.4% of the boys had central adiposity. Thirteen per cent of the children were hypertensive. The optimal WHtR cut-off value to identify children with hypertension was 0.41 in both boys and girls. Positive correlations were observed between anthropometric indices. Using linear regression analyses, age and body mass index were significant predictors of high blood pressure in boys, while for girls it was height and weight. Results suggest that adopting a WHtR cut-off value < 0.5 could enhance the use of WHtR as a marker for high blood pressure in children.