title: Interaction of clothing and body mass index affects validity of air-displacement plethysmography in adults.
abstract: OBJECTIVE
  We determined the effect of clothing type on the validity of air-displacement plethysmography (ADP) to estimate percentage of body fat (%BF) and ascertain if these effects differ by body mass index (BMI).
  
  
  METHODS
  The %BF by dual x-ray absorptiometry (DXA) and %BF, density, and body volume by ADP were assessed in 132 healthy adults classified by normal (N; 18.5-24.9 kg/m2), overweight (OW; 25-29.9 kg/m2), and obese (OB; 30-39.9 kg/m2) BMIs.
  
  
  RESULTS
  Compared with DXA, ADP underestimated (P < 0.0001) %BF from scrubs (SC) and t-shirt/shorts (TS) in N (11.4%; 8.6%) and OW (6.8%; 4.9%) BMI groups, respectively. ADP compared with DXA overestimated (P < 0.0006) %BF in the OW group (1.2%), but underestimated (P < 0.0001) it in the N group (2.4%). ADP also overestimated (P < 0.006) %BF in the OB group wearing spandex (SP; 4.8%), but not in those wearing SC (0.7%; P = 0.10) and TS (0.5%; P = 0.22) versus DXA.
  
  
  CONCLUSIONS
  All three clothing types showed significant error in estimating %BF with ADP compared with DXA in N and OW BMI. Use of spandex provided the least error and is the preferred attire to obtain valid body composition results when testing N and OW subjects. However, SP provided the greatest error in the OB group. Error in ADP %BF in OB was minimal in SC and TS and similar to the within-subject variability in %BF estimates with ADP. Thus, TS and SC are acceptable alternatives to SP in adults with excess body weight.
authors: U.S. Department of Agriculture, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, North Dakota, USA.
authors: Kimberly J
authors: KJ
authors: Shafer
authors: William A
authors: WA
authors: Siders
authors: LuAnn K
authors: LK
authors: Johnson
authors: Henry C
authors: HC
authors: Lukaski
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods / Q000592:standards; D000273:Adipose Tissue; D000328:Adult; D000368:Aged; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D003020:Clothing; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology; D050177:Overweight / Q000503:physiopathology; D010993:Plethysmography, Whole Body / Q000379:methods / Q000592:standards*; D013851:Thinness / Q000503:physiopathology