A Comparison of Bio-electrical Impedance Method and Skinfold Measure of Body Composition

Lee, Kyung Jin; Kim, Nan Soo; Kim, Hyun Soo

Abstract

BACKGROUND: Body composition for assessing body fat content and its distribution has been extensively measured in healthy, obese, children, and elderly subjects. Various techniques have been developed to assess body composition in those subjects. The use of bioelectrical impedance analysis (BIA) to estimate body composition is based on the different conductive and electric properties of various biological tissues at various frequencies of current. The objective of this study was to compare the body composition data obtained by using three different methods such as underwater weighing (UW), BIA and skinfolds thickness (SFT) in women (n = 80) and men (n = 47).
METHODS
Mean values of percent body fats (%BF) measured by the three methods were used to compare their relative validation by using the standard error of estimate and Bland-Altman method.
RESULTS
In men, mean %BF assessed by UW, BIA, and SFT methods, were (19.8 +/- 6.9)%, (21.8 +/- 4.8)%, and (23.5 +/- 8.9) %, respectively. In women, mean %BF were 30.8 +/- 6.5%, 28.9 +/- 4.6%, and 32.1 +/- 6.2%, respectively. Pearson product moment bivariate correlations among the %BF between the three methods were high, ranging from 0.92 to 0.88 (P < 0.001). Based on the criterion measure of UW, however, BIA and SFT revealed a different magnitudes of agreement. The absolute mean difference in %BF was 0.4 +/- 3.8% between UW and BIA measures, and it was -2.2 +/- 4.1% between UW and SFT in men. Compared to the UW, the BIA and SFT tended to overestimate as much as by 0.7% and 3.4%, respectively.
CONCLUSION
Compared to the SFT, the hand-to-foot BIA method appears to have a higher accuracy in assessing percentage of body fat of the adult.