Prediction of fat-free body mass from bioelectrical impedance among 9- to 11-year-old Swedish children.

Aim: Predictive equations for estimating body composition from bioelectrical impedance analysis (BIA) among Scandinavian children are lacking. In the present study, equations for estimation of fat-free body mass (FFM) and lean tissue mass (LTM) were developed and cross-validated from BIA using dual-energy X-ray absorptiometry (DXA) as the reference measurement of body composition. Methods: The study population consisted of 49 girls and 52 boys aged 9–11 years from Malmö, Sweden. Bioelectrical impedance was measured between hand and foot at 50 kHz. Predictive equations were developed by multiple linear regression and cross-validated against DXA measurements of body composition. Results: FFM was predicted from BIA and anthropometric variables with an adjusted R2= 0.95 and root mean square error (RMSE) = 0.84 kg, and LTM was predicted with an adjusted R2= 0.95 and RMSE = 0.87 kg. Cross-validation revealed a mean RMSE = 0.95 kg FFM and a mean RMSE = 0.96 kg LTM. Prediction of body composition from equations developed in previous literature was mixed when applied to the present cohort of children. Conclusions: FFM and LTM are predicted with sufficient accuracy at the population level. We recommend that the predictive equations developed in the present study are used in prepubescent European children aged 9–11 years only in order to minimize confounding of results because of possible differences in population samples. [ABSTRACT FROM AUTHOR]