Body Composition Analysis by Using Bioelectrical Impedance in a Young Healthy Chinese Population: Methodological Considerations

Objective: To develop a new bioelectrical impedance analysis (BIA) model for analyzing body composition by using isotope dilution, magnetic resonance imaging (MRI), and dual-energy X-ray absorptiometry (DEXA) as the reference methods in young healthy Chinese populations. Methods: Thirty healthy participants were enrolled. Their body composition was analyzed using BIA and 3 reference methods. We established a model that uniformed data from 3 references methods (isotope, MRI, and DEXA) into 1 formula. This model was further validated with 209 participants. Results: The following BIA body composition adjustment model was developed: Y = 1.072 Xe-(k-1.786/1.77)2 + 0.3194K(2) - 2.073K + 3.713 , where X represents the impedance index; when K = 1, 2, and 3, Y represents total body water, fat mass, and bone mass, respectively. The prediction accuracy of this formula was 93.3%. By incorporating the data matrix, the protein mass was calculated using BIA: Protein = 1: 01 x (BW - FM - BM - TBW) + 1: 29. In the verification part of this study, the lean body mass measured using DEXA and BIA was 43.02+ 8.34 kg and 45.85 + 8.81 kg, respectively. Analysis indicated that the model fit was extremely favorable (R-2 =.9997, P < .001). Conclusions: The accuracy of BIA measurement on body composition and protein mass is significantly improved by our work.