The validity of predicted body composition in Chinese adults from anthropometry and bioelectrical impedance in comparison with densitometry.

Body composition was measured by densitometry in a group of eighty-one Chinese males and 124 healthy Chinese females, aged 18-67 years. Biceps, triceps, subscapular and suprailiac skinfolds were measured as well as total body bioelectrical impedance at 50 kHz. Mean heights were 1.71 (SD 0.05) and 1.61 (SD 0.06) m, body weights 66.1 (SD 9.1) and 57.2 (SD 9.4) kg and BMI 22.7 (SD 3.0) and 22.0 (SD 3.3) kg/m2 in males and females respectively. Body fat values from body density were 20.1 (SD 6.2) and 29.7 (SD 7.5)% in males and females respectively. Mean predicted body-fat values from skinfolds, bioelectrical impedance and BMI, using prediction formulas developed in Western populations, did not differ or differed only slightly from body-fat values estimated from body density. The SD of the difference for each method was 5% body fat or 3.3 kg fat-free mass (CV 6%), which is approximately equal to the accuracy level of each predictive method. Compared with densitometry the predictive methods overestimated body fat at the lower levels of body fatness, whereas at the higher levels of body fat the predictive methods tended to underestimate body fatness. It is concluded that prediction formulas for estimating body fat from skinfolds, impedance or BMI developed in Western populations are applicable and valid in the adult Chinese population. However, in very lean subjects the predictive methods overestimate body fat compared with values obtained from body density.