Background/Purpose
Bioelectrical impedance analysis (BIA) has been widely used as a method of assessing body composition. Foot-to-foot (F-BIA) and hand-to-hand (H-BIA) devices provide the general public with a good means of assessing body fat (%BF). Instrumentation is an important factor to affect accuracy of BIA methods estimating %BF. In a study of Japanese men, the mean difference between reference and predicted %BF values was slightly smaller for H-BIA than for F-BIA analyzers. The aim of this study was to investigate if there had differences in %BF estimates measured by two BIA analyzers in college male students.
Method
Forty-nine participants (aged 18-24 yrs) were recruited, with 20 students from physical education (PE) and 29 in Non-PE majors. The study was explained and the informed consent was signed before testing. BIA measurements were taken by using the Omron Body Fat Analyzer: F-BIA (Model HBF-400) and H-BIA (Model HBF-306BL). Subjects were measured following the manufacturer instructions and other guidelines. Data were analyzed using SPSS for Windows. Correlations were examined using Pearson's correlation coefficients. Differences in variables within and between groups were tested using t-test. The significant level was set at p ≤ 0.05. Values are presented as means±SD.
Analysis/Results
There were no mean differences in terms of subject age, height, weight, BMI, and %BF of upper- and lower-body between two groups. The %BF estimated by H- and F-BIA methods was 14.57±8.98 and 22.39±8.56 for PE students and 12.07±6.28 and 22.26±4.29 for Non-PE. There was a very high relationship between %BF estimates from two devices for PE group (r=0.851, p<0.0001), but a low relationship for Non-PE (r=0.226, p=0.238). Significant differences were noted between two %BF values measured by H- and F-BIA in both groups: the mean difference of 7.84±4.80, the 95% CI of 5.59 to 10.09, t=7.297 (p<0.0001) for PE group, and 10.19±6.76, 7.62 to 12.76, t=8.117 (p<0.0001) for Non-PE, respectively.
Conclusions
The results of this study indicated that regardless of student major, %BF estimates was much higher by using the F-BIA than the H-BIA, approximately 7.8% to 10.2% of difference. The mean difference in estimating %BF was more in Non-PE group; but the error of estimation tended to be greater in PE group. For Non-PE students, %BF estimates measured by two BIA devices may not be corresponded. It is important to consider variability of %BF estimates while using different BIA devices. Using the same BIA device consistently is strongly recommended for assessing %BF.