Comparison of body fat measurement by dual-energy absorptiometry and bioelectric impedance analysis

Objective: To compare the percentage of body fat (%BF) measured by dual-energy X-ray absorptiometry (DEXA) and by bioelectric impedance analysis (BIA). Material and Methods: Between November 2000 and November 2002, the data of subjects undergoing body fat measurement at Songklanagarind Hospital were analyzed. The body fat of all subjects was measured using both DEXA and BIA. DEXA is a standard measurement in this hospital. Demographic data and percent body fat were analyzed. Results: Two hundred and forty nine subjects, 52 males and 197 females, were included in the study. Mean percentage body fat by DEXA was 28.05 ± 8.19 in males and 39.21 ± 6.85 in females. Mean percentage of body fat by BIA was 26.95 ± 6.31 in males and 33.62 ± 6.10 in females. The correlation between DEXA and BIA is good, R = 0.853 (p < 0.001), however, the mean body fat measurement by BIA was significantly lower than that by DEXA in females. Conclusion: There was a good correlation between DEXA and BIA, but the differences were statistically significant in females. BIA may still be useful to dietitians who wish to monitor changes in body fat over the long term.