Body mass index as a measure of body fatness: age- and sex-specific prediction formulas

Paul Deurenberg, Jan A. Weststrate, Jaap C. Seidell
1991 British Journal of Nutrition  
In 1229 subjects, 521 males and 708 females, with a wide range in body mass index (BMI; 13.9-40.9 kg/m2), and an age range of 7-83 years, body composition was determined by densitometry and anthropometry. The relationship between densitometrically-determined body fat percentage (BF%) and BMI, taking age and sex (males = 1, females = 0) into account, was analysed. For children aged 15 years and younger, the relationship differed from that in adults, due to the height-related increase in BMI in
more » ... ncrease in BMI in children. In children the BF% could be predicted by the formula BF% = 1.51 x BMI-0.70 x age -3.6 x sex + 1.4 (R2 038, SE of estimate (SEE) 4.4% BF%). In adults the prediction formula was: BF% = 1.20 x BMI+0.23 x age-10.8 xsex-54 (R2 079, SEE = 41% BF%). Internal and external cross-validation of the prediction formulas showed that they gave valid estimates of body fat in males and females at all ages. In obese subjects however, the prediction formulas slightly overestimated the BF%. The prediction error is comparable to the prediction error obtained with other methods of estimating BF%, such as skinfold thickness measurements or bioelectrical impedance. Data from 1229 healthy subjects, 521 males and 708 females, were used in the present study. All subjects participated as volunteers in studies on body composition or energy metabolism of which the protocols were approved by the Ethical Committee of the Department of Human Nutrition. The subjects showed a wide age range (7-83 years) and ranged in BF% from 5 to 50. The BMI ranged from 13.9 to 40.9 kg/m2. The total group of subjects was randomly divided into two groups: group A, and a cross-validation group B. To facilitate the preliminary crude analysis on the age dependency of the relation between BF% and BMI, the population was divided into nine age groups: group 1, 7-10 years; group 2, 11-15 years; group 3, 16-20 years; group 4, 21-25 years; group 5, 26-35 years; group 6, 3 6 4 5 years; group 7 , 46-55 years; group 8, 56-65 years; group 9, 3 66 years. Body-weight was measured to the nearest 005 kg with a digital scale (Berkel ED6O-T, Rotterdam, The Netherlands). Body height was measured by means of a rnicrotoise to the
doi:10.1079/bjn19910073 pmid:2043597 fatcat:j6izlbfofzfjxmmm26ooznunyy