Cross validation of bioelectrical impedance equations for men

Resumen

The purpose of this study was to analyze the cross validity of bioimpedance equations (BIA) on the estimation of the fat free mass (FFM) of 44 men, with mean age of 24.98 ± 3.40 years and relative body fat (%BF) of 17.15 ± 6.41%. A dual energy x-ray absorptiometry was used as a reference method for %BF and FFM. Total body resistance was assessed by the Biodynamics (Model 310). The equations analyzed in this study were: two equations (Eq.1 and 2) developed by Carvalho e Pires Neto (1998); one equation (Eq. 3) developed by Rising et al. (1991); one equation (Eq. 4) developed by Oppliger et al.(1991); two equations (Eq. 5 (%FM < 20%) and Eq. 6 (%FM ? 20%) developed by Segal et al. (1988). The validation criteria proposed by Lohman (1991) was used in this study. The correlations were high and significant oscillating from 0.906 (Eq. 2) to 0.981 (Eq. 6). The equations 1 to 5 significantly overestimated (p < 0.001) FFM and the mean differences ranged from 1.32 kg (Eq. 5) to 5,90 kg (Eq. 4). The equation 6 met all the validity criteria. The validity coefficient was r = 0.981 and the mean difference was -0.38 kg. The Segal et al.(1988) fatness specific equation (Eq. 6) for men (%FM ? 20%) was the only one that met the concurrent validity criteria. The equation 6 showed a non significant difference on FFM and the standard error of estimate was 0.90kg.