Development of bioelectrical impedance analysis prediction equations for body composition with the use of a multicomponent model for use in epidemiologic surveys
Shumei S Sun, W Cameron Chumlea, Steven B Heymsfield, Henry C Lukaski, Dale Schoeller, Karl Friedl, Robert J Kuczmarski,
Katherine M Flegal, Clifford L Johnson, and Van S Hubbard
Background: Previous studies to develop and validate bioelectrical impedance analysis (BIA) equations to predict body composition were limited by small sample sizes, sex specificity, and reliance on reference methods that use a 2-component model.
Objective: This study was designed to develop sex-specific BIA equations to predict total body water (TBW) and fat-free mass (FFM) with the use of a multicomponent model for children and adults.
Design: Data from 5 centers were pooled to create a sample of 1474 whites and 355 blacks aged 12–94 y. TBW was measured by dilution, and FFM was estimated with a multicomponent model based on densitometry, isotope dilution, and dual-energy X-ray absorptiometry.
Results: The final race-combined TBW prediction equations included stature2/resistance and body weight (R2 = 0.84 and 0.79 and root mean square errors of 3.8 and 2.6 L for males and females, respectively; CV: 8%) and tended to underpredict TBW in black males (2.0 L) and females (1.4 L) and to overpredict TBW in white males (0.5 L) and females (0.3 L). The race-combined FFM prediction equations contained the same independent variables (R2 = 0.90 and 0.83 and root mean square errors of 3.9 and 2.9 kg for males and females, respectively; CV: 6%) and tended to underpredict FFM in black males (2.1 kg) and females (1.6 kg) and to overpredict FFM in white males (0.4 kg) and females (0.3 kg).
Conclusion: These equations have excellent precision and are recommended for use in epidemiologic studies to describe normal levels of body composition.