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 (Z(F-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 (Z(H-F)). In order to cross match analysis, both of the Z(H-F) and Z(F-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 Z(F-F) value was 481.85 +/- 63.37 ohm in male and 554.35 +/- 74.97 ohm in female. The Z(H-F) value was 586.82 +/- 81.56 ohm in male and 703.28 +/- 97.70 ohm in female. Regression equations for Z(F-F) and Z(H-F) were Z(F-F) = 0.926 Z(H-F) - 63.093, (R = 0.85) in male and Z(F-F) = 0.909 Z(H-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 Z(F-F) to DEXA was 0.93 and for Z(H-F) was 0.96 in male, and 0.85 and 0.87 in female, respectively. The high correlation between Z(H-F) and Z(F-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.