Air displacement plethysmography for fat-mass measurement in healthy young women.

摘要

Purpose: Dual energy X-ray absorptiometry (DXA) and air displacement plethysmography (ADP) are commonly used to assess body composition. Accurate body fat measures are valuable in a variety of populations. Because DXA, the reference standard, is expensive and labour-intensive, determining whether these two methods are interchangeable is important. Methods: Forty-five female undergraduate students aged 21 to 33 with body mass indexes of 18.3 to 28.6 kg/m2 were recruited from the University of Guelph. Each participant underwent one full-body DXA scan and one ADP assessment, to determine total percent fat mass (%FM). Results: The Pearson's correlation between %FM_DXA (27.1+or-4.8) and %FM_ADP (26.1+or-5.5) indicated good association (r=0.88, p<0.01). While Bland-Altman analysis revealed no systematic bias between the two methods (R2=0.07, p=0.08), large intraindividual variation occurred (95% confidence interval: -5.86% to 4.11%); this was related to height, weight, body-surface area, and lung volume. Conclusions: The two methods were significantly correlated. Mean %FM was not significantly different and no systematic bias between methods was observed. These findings indicate that ADP and DXA may be used interchangeably for determining %FM at the group level in healthy young women; a large intraindividual variation between the methods precludes interchangeability at the individual level.Digital Object Identifier http://dx.doi.org/10.3148/72.2.2011.85