Abstract

Waist circumference (WC) is proposed as a better marker in the diagnosis of metabolic syndrome in children than body mass index (BMI). As important as this anthropometric index may appear, it is not as commonly measured in schools as BMI. Thus unlike BMI, data on WC are scarce. Therefore, we investigated whether there is an alternative way to estimate WC even in those children whose WC measurement has not been taken. We evaluated the relationship between BMI and the WC of 1136 schoolchildren (548 boys; 588 girls) aged 9 to 13 years, attending public primary schools in Pretoria Municipality, South Africa. The measurements were taken using the protocol of International Society for the Advancement of Kinanthropometry (ISAK). Significant linear relationship between BMI and WC were observed in each age-and sex-stratified groups [(9-year-old boys: waist = 0.17 + 3.03 BMI (r = 0.65, p < 0.001); 9-year-old girls: waist = 26.24 + 1.73 BMI (r = 0.95, p < 0.001); 10-year-old boys: waist = 19.64 + 2.21 BMI (r = 0.90, p < 0.001); 10-year-old girls: waist = 18.36 + 2.13 BMI (r = 0.81, p < 0.001); 11-year-old boys: waist = 25.88 + 1.89 BMI (r = 0.78, p < 0.001); 11-year-old girls: waist = 23.08 + 1.97 BMI (r = 0.94, p < 0.001); 12-year-old boys: waist = 27.50 + 1.80 BMI (r = 0.72, p < 0.001); 12-year-old girls: waist = 26.26 + 1.92 BMI (r = 0.91, p < 0.001); 13-year-old boys: waist = 25.46 + 2.05 BMI (r = 0.91, p < 0.001); 13-year-old girls: waist = 24.59 + 1.96 BMI (r = 0.84, p < 0.001)]. The result indicates the possibility of estimating WC from stature and body mass, at least among South Africa children. WC could be used as an alternative way of screening childhood metabolic syndrome or obesity in which waist circumference is essential.

Key words: Waist circumference, BMI, South African children.