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

Abstract

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.

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).