Validation of tetrapolar bioelectrical impedance method to assess human body composition

TLDR

This study aimed to validate the relationship between bioelectrical conductance (ht²/R) and densitometrically determined fat‑free mass, and to compare prediction errors of body‑fat estimates from the tetrapolar impedance method versus skinfold thicknesses, using hydrodensitometry as reference. The study involved 114 adults aged 18–50 with a wide range of fat‑free mass (34–96 kg) and percent body fat (4–41 %). The tetrapolar impedance method produced highly correlated fat‑free mass estimates (r = 0.979 for males, r = 0.954 for females), with regression coefficients similar across sexes, and yielded lower predictive error (2.7 % vs 3.9 %) than skinfold thicknesses, confirming its validity and reliability for body‑composition assessment in healthy adults.

Abstract

This study was conducted to validate the relationship between bioelectrical conductance (ht2/R) and densitometrically determined fat-free mass, and to compare the prediction errors of body fatness derived from the tetrapolar impedance method and skinfold thicknesses, relative to hydrodensitometry. One-hundred and fourteen male and female subjects, aged 18–50 yr, with a wide range of fat-free mass (34–96 kg) and percent body fat (4–41%), participated. For males, densitometrically determined fat-free mass was correlated highly (r = 0.979), with fat-free mass predicted from tetrapolar conductance measures using an equation developed for males in a previous study. For females, the correlation between measured fat-free mass and values predicted from the combined (previous and present male data) equation for men also was strong (r = 0.954). The regression coefficients in the male and female regression equations were not significantly different. Relative to hydrodensitometry, the impedance method had a lower predictive error or standard error of the estimates of estimating body fatness than did a standard anthropometric technique (2.7 vs. 3.9%). Therefore this study establishes the validity and reliability of the tetrapolar impedance method for use in assessment of body composition in healthy humans.