The validity and accuracy in foot-to-foot bioelectrical impedance analysis measuring models referenced by dual-energy X-ray absorptiometry in body composition in standing position
The criterion validity of foot-to-foot (ZF-F) by bioelectrical impedance analysis (BIA) in a standing position measuring models was referenced by dual-energy X-ray absorptiometry (DEXA) and hand-to-foot (ZH-F). In order to cross match analysis, both of the ZH-F and ZF-F measuring by BIA were performed in the same event to the identical subject, simultaneously. 105 males (7 to 70 years old) and 108 females (7 to 67 years old) were measured by BIA and DEXA. The ZF-F value was 481.85 ± 63.37 ohm in male and 554.35 ± 74.97 ohm in female. The ZH-F value was 586.82 ± 81.56 ohm in male and 703.28 ± 97.70 ohm in female. Regression equations for ZF-F and ZH-F were ZF-F = 0.926 ZH-F - 63.093, (R = 0.85) in male and ZF-F = 0.909 ZH-F - 86.673 (R = 0.86) in female. The fat free mass (FFM), measured by DEXA was 49.42 ± 10.03 kg in male and 34.52 ± 4.45 kg in female. The correlation (R value) for ZF-F to DEXA was 0.93 and for ZH-F was 0.96 in male, and 0.85 and 0.87 in female, respectively. The high correlation between ZH-F and ZF-F vs. whole body DEXA in both male and female renders it applicable to develop the clinical instrument by foot-to-foot measuring models by BIA in standing position.
Key words: Hand-to-foot bioimpedance analysis, foot-to-foot bioimpednace analysis, relative body fat (BF), fat free mass (FFM), dual-energy X-ray absorptiometry (DEXA).