The validity of predicted body fat percent in Chinese children with Caucasian prediction formulas.

Body composition was measured by underwater weighing and by anthropometry and bio-electrical impedance in 165 Chinese boys and 150 Chinese girls, aged 7 to 17 years and living in Beijing. Until age 12 years there were no differences in body weight, body height and body mass index (kg/m2) between boys and girls, but body fat from density was slightly higher in girls. After age 12 boys had higher body weights, body heights and body mass index but lower body fat as calculated from body density. Predicted body fat from body mass index, body impedance and skinfold thickness was generally slightly lower compared to body fat from body density, except for body fat from impedance, which was both in boys and in girls slightly higher compared to body fat from body density. However, the mean differences were small and maximally reached 2.7% body fat in boys (impedance) and 1.7% in girls (skinfolds). The standard deviations of the differences were within the estimation error of the used methodology and comparable with values obtained in other studies. The differences between measured and predicted values were slightly higher in the youngest and the oldest children, probably indicating invalid assumptions in the used methodologies at these ages. At the lower level of body fatness all prediction formulas systematically overestimated body fat, and at higher fat levels body fat was systematically underestimated. It is concluded that prediction formulas developed in Caucasian subjects are generally valid in Chinese (Beijing) children.