Estimation of lean body mass by bioelectrical impedance analysis compared to skinfold anthropometry

Estimation of lean body mass (LBM) is an important procedure in nutritional assessment and the availability of a rapid, portable and reproducible method would be desirable for this purpose. At present, only bioelectrical impedance analysis (BIA) and skinfold anthropometry are applicable for clinical use. We compared the prediction of LBM by these two methods in 80 subjects stratified into four subgroups by body mass index (BMI): lean, normal, obese and super-obese. Highly significant correlation coefficients (r > 0.92, P < 0.001) were seen for all subgroups with a mean difference between techniques (LBM(anthro) - LBM(BIA)/LBM(anthro) x 100) of < 1 kg or 1 per cent error. A greater s.d. and error was noted in the super-obese (BMI ≥ 40.0). Fifteen subjects had measurements repeated after a mean weight loss of 10 per cent. Although mean difference between methods was not statistically significant, there was a large individual variation. It is concluded that there is an excellent agreement between the estimation of LBM by bioelectrical impedance and skinfold anthropometry in the weight-stable subject.