Estimation accuracy of percent total body fat and percent segmental fat measured by single-frequency bioelectrical impedance analysis with 8 electrodes: the effect of difference in adiposity.
OBJECTIVE
This study aimed to compare the accuracy of percent total body fat (%TBF) and percent segmental fat (%SF) measurements of new automatic single-frequency bioelectrical impedance analysis with 8 electrodes (SF-BIA8), referenced to the dual-energy X-ray absorptiometry (DXA), between different fatness level female groups.


METHODS
Subjects were 34 overweight females (OWG) and 24 normal females (NG). This study used the BIA analyzer of Tanita BC-118 which is a commercially available single frequency bioelectrical impedance analysis system with 8 tactile electrodes.


RESULTS
Test-retest reliability in each method was high (intra-class correlations > or =0.96). The SF-BIA8 tends to overestimate %TBF and %SF in the lower extremities and trunk compared with DXA, and consistency with DXA was especially low in %SFs in the lower extremities (left leg: r=0.475, SEE=4.673, right leg: r=0.494, SEE=4.772). Systematic errors regarding to the difference in fatness were found in %TBF and %SFs in lower extremities in OWG, and were found in %SF in upper extremities in NG. Furthermore, systematic errors regarding to the difference in body fat distribution were found in %SFs in lower extremities in OWG, and found in %SFs in upper extremities and trunk in NG.


CONCLUSIONS
SF-BIA can provide highly reproducible measurements of %TBF and %SF, but systematic errors based on the differences in fatness and body fat distribution were found. An improved prediction equation considering a variety in fat and body fat distribution will be needed in further investigations.
Demura
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Faculty of Education, Kanazawa University, Kanazawa, Japan.
Sato
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Kitabayashi
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D015502:Absorptiometry, Photon; D050154:Adiposity / Q000502:physiology*; D000328:Adult; D017097:Electric Impedance; D004566:Electrodes; D005260:Female; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results