Waist circumference estimation from BMI in Japanese children

Abstract

Waist circumference, not BMI, is one of the factors in the definition of metabolic syndrome in adults. In children, waist circumference is also a well known predictor of metabolic syndrome. However, waist circumference measurement is not as commonly recorded as weight and height measurements in physical examinations in schools. This means BMI data is available for every child, but waist circumference is not. Therefore, we investigated whether there is an alternative way to estimate waist circumference even in those children whose waist circumference measurement has not been taken. We evaluated the relationship between BMI and the waist circumference of schoolchildren using a relatively large-scale population-based cohort in Japan. There was a significant linear relationship between BMI and waist circumference noted in each age- and sex-divided group [9–10-year-old boys: waist = 13.99 + 2.63BMI ( r = 0.940, p < 0.001), 9–10-year-old girls: waist = 15.09 + 2.61BMI ( r = 0.933, p < 0.001), 12–13-year-old boys: waist = 23.67 + 2.22BMI ( r = 0.880, p < 0.001), 12–13-year-old girls: waist = 23.83 + 2.15BMI ( r = 0.859, p < 0.001)]. This means it is possible to estimate waist circumference from height and weight, at least among those age groups of children in Japan. This estimation could be an alternative way and useful in detecting childhood metabolic syndrome or obesity disease in which a waist circumference figure is necessary.