title: Predictive accuracy of bioimpedance in estimating fat-free mass of African-American women.
abstract: The purpose of this study was to identify the BIA (bioimpedance analysis) equation that yields the best estimate of body composition for 122 premenopausal African-American women (18-40 yr). Total body density (Db) was determined by hydrodensitometry at residual lung volume and converted to %BFHD using the Siri (31) formula, %BFHD was used to calculate reference fat-free mass (FFM). Resistance and reactance were measured using a Valhalla bioimpedance analyzer. The predictive accuracy of generalized, age-gender, race-specific, fatness-specific, and the Valhalla manufacturer's BIA equations was compared. There were significant correlations between FFMHD and FFMBIA for all BIA equations (r = 0.85 to 0.92). Except for the modified Segal fatness-specific equations, the prediction errors (SEE and E) exceeded 2.8 kg. For individuals, the %BF derived from FFMBIA predicted by the modified Segal equations was within +/- 3.5% BF for 69% of the subjects. This percentage was less (34-53%) for other equations. These results suggest that the predictive accuracy of BIA for estimating body composition of African-American women is improved when fatness-specific equations are used. We recommend using the modified Segal fatness-specific equations to assess FFM and %BF of premenopausal African-American women.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, University of South Carolina, Columbia 29208, USA. BAINSWORTH@SPH.SCAROLINA.EDU
authors.forename: B E
authors.initials: BE
authors.lastname: Ainsworth
authors.forename: L M
authors.initials: LM
authors.lastname: Stolarczyk
authors.forename: V H
authors.initials: VH
authors.lastname: Heyward
authors.forename: C B
authors.initials: CB
authors.lastname: Berry
authors.forename: M L
authors.initials: ML
authors.lastname: Irwin
authors.forename: L M
authors.initials: LM
authors.lastname: Mussulman
mesh_terms: D000273:Adipose Tissue; D000293:Adolescent; D000328:Adult; D044383:Black People; D001823:Body Composition; D017097:Electric Impedance; D005260:Female; D006801:Humans; D011237:Predictive Value of Tests; D001741:Black or African American