Comparison of body composition methods: a literature analysis.
OBJECTIVE
To examine the comparability of different methods to assess percentage body fat (BF%) against underwater weighing (UWW).


METHODS
A meta-analysis on 54 papers, published in 1985-96, on healthy, adult Caucasians.


METHODS
The mean BF% from different studies were treated as single data points. In addition to UWW, the studies included one or more of the following methods: 3- or 4-component model, dual-energy X-ray absorptiometry (DXA), dual-energy photon absorptiometry, isotope dilution, bioimpedance (BIA), skinfolds or near-infrared interactance (NIR). Within each of the methods, the analyses were done separately for different mathematical functions, techniques or instruments.


METHODS
Bias (mean difference) and error (s.d. of difference) between BF% measured by UWW and the other methods.


RESULTS
The 4-component model gave 0.6 (95% confidence interval for the mean, CI: 0.1 to 1.2) BF% higher results than UWW. Also the 3-component model with body density and total body water (+1.4 BF%, 95% CI: +0.3 to +2.6), deuterium dilution (+1.5 BF%, 95% CI: +0.7 to +2.3), DXA by Norland (+7.2 BF%, 95% CI: 2.6 to 11.8) and BIA by Lukaski et al. (+2.0 BF%, 95% CI: 0.2 to 3.8) overestimated BF%, whereas BIA by Valhalla Scientific (-2.6 BF%, 95% CI: -4.5 to -0.6) and skinfold equations by Jackson et al. (-1.20, 95% CI: -2.3 to -0.1) showed a relative underestimation. The mean bias for the skinfold equation by Durnin & Womersley, against UWW, was 0.0 BF% (95% CI: -1.3 to 1.3). The correlation between the size of measurement and the mean difference was significant for only NIR (r = -0.77, P = 0.003).


CONCLUSIONS
The difference between any method and UWW is dependent on the study. However, some methods have a systematical tendency for relative over- or underestimation of BF%.
Fogelholm
M
M
UKK Institute, POB 30, FIN-33501, Tampere, Finland.
van Marken Lichtenbelt
W
W
D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000886:Anthropometry; D001823:Body Composition / Q000502:physiology*; D017097:Electric Impedance; D006801:Humans; D016239:MEDLINE; D015201:Meta-Analysis as Topic; D008954:Models, Biological; D011865:Radioisotope Dilution Technique; D012680:Sensitivity and Specificity; D044465:White People