Body mass index – proposed norms for children and youths

Abstract

The aim of the study was to establish normal BMI values vs. age for children and youths having normal body fat content and to confront them with Cole’s cut-off points. In cohorts of 1373 boys and 1805 girls, aged 7–20 years, body fat content was determined from 3 skinfolds (triceps, subscapular, abdominal) using Slaughter’s equations. Next, 1069 boys and 759 girls with acceptable fat percentage (NF groups) were selected and for them log BMI values were computed. Equations of log BMI vs. age (means and SD) computed for NF groups served to present the proposed BMI norms. The obtained upper limits (mean log + 2SD) for boys and girls aged 19 years were 24.6 and 24.5, respectively, and the corresponding body fat contents –23.7 and 24.1, respectively. Inasmuch BMI does not reflect the real body fat content, the presented norms, based on acceptable body fat content, seem to reflect the weight-height relations better than those derived from unselected population data.