Comparison of Bioelectrical Impedance and Skinfolds with Hydrodensitometry in the Assessment of Body Composition in Healthy Young Adults

Bioelectrical impedance analysis (BIA) is a widely used method for estimating body composition, yet issues concerning its validity persist in the literature. The purpose of this study was to validate percentage of body fat (BF) values estimated from BIA and skinfold (SF) with those obtained from hydrodensitometry (HD). Percent BF values measured via hand-to-hand BIA (BIAH), foot-to-foot BIA (BIA-F), sum of three skinfolds (SF-3), and sum of seven skinfolds (SF-7) were compared to HD in 64 young caucasian adults (33 males, 31 females, mean age ± SD = 21.2 ± 3.4 years) in the same morning. Correlations with HD ranged from r = .71 .73 except for (BIA-F), which was r = .63. BIAF significantly overpredicted body fatness (%BF) (t = 3.8, p < .001) in comparison with HD. BIA-H, SF-3, and SF-7 were not significantly different (SE = 0.78 .83) from HD. Caution should be exercised when using BIA-F based on existing manufacturer’s equations with young adults. These data suggest that BIA-H can produce acceptable body fat measures for young adults but is not superior to SF-3 estimates.