Object: Obesity is defined as “heperaccumulation of body fat. So in diagnosis of obesity, the accurate measurement of body fat is very important. The recent development of bioelectrical impedance analysis(BIA) method made it possible to analyze percent body fat more easily. We performed this study for two purposes. The first is to evaluate the precision error of percent body fat measurement by bioelectrical impedance analysis(Inbody 2.0, Biospace Soul Korea) method. The second is to evaluate the correlation between densitometry and bioelectrical impedance analysis(BIA), body mass index(BMI) and Broca's method in body composition analysis.
Method: To evaluate the precision error of BIA method, 7 health subjects(M;3, F;4) were selected. Percent body fat measurement by BIA method was performed one time a day for 10 days. To evaluate the correlation between densitometry and BIA(Inbody 2.0, Biospace Soul Korea), BMI, and Broca method, 23 health subjects(M;10, F;13) were selected. To these subjects we measured height, weight, and percent body fat by BIA and densitometry. The Brozek's formula was used for percent body fat calculation by hydrodensitometry method. To assess the precision error of the measurement, we performed descriptive analysis by using SPSS statistic package. To assess the correlation, we performed bivariate correlation analysis and age controlled partial correlation analysis.
Results: The precision error of BIA method in percent body fat measurement was 3.4%. The precision error of densitometry method was 3.0%. In bivariate correlation analysis, there were statistically significant correlation between densitometry and BIA method(r = 0.85, P < 0.001). In bivariate correlation analysis, there were no statistically significant correlation between densitometry and BMI, Broca method. In age controlled partial correlation analysis, there were statistically significant correlation between densitometry and BIA, BMI and Broca's metheod. The correlation coefficients were 0.82(P < 0.001), 0.46(P = 0.038), and 0.44(P = 0.048) respectively.
Conclusion: Precision error of BIA(Inbody 2.0) method was 3.4%. The correlation of between densitometry and BIA was statistically more significant than that of between densitometry and BMI, and Broca's method. When we diagnose obesity, considering percent body fat which measured by BIA method as well as anthropometric indices is more reasonable than that of anthropometric indices alone.

Keywords: BIA, Densitometry, BMI, Broca, Body composition