title: Air-displacement plethysmography for the measurement of body composition in children aged 6-48 months.
abstract: BACKGROUND
  Air-displacement plethysmography (ADP) is an age-appropriate method for measuring relative fat mass (%FM) in children; however, the accuracy of this method has not been evaluated in children aged 5 y or younger.
  
  
  RESULTS
  Mean %FM values measured by ADP (17.9 ± 8.0%) and by total body water (TBW) (23.7 ± 6.3%) were significantly different (P < 0.001). Regression analysis of %FM by ADP vs. TBW provided a line of best fit with a slope of 0.089, r(2) = 0.013, and standard error of the estimate (SEE) = 6.3% FM (P = 0.40).
  
  
  CONCLUSIONS
  The error was related to child weight and %FM, but not to behaviors (movement or vocalizations) occurring during the test sequence. A large portion of the error was attributable to imprecision in measuring small volumes. As currently designed, ADP is not an accurate method for measuring %FM in young children. Further investigation of the sources of variability will provide insight into ways of improving the accuracy of this technology for this population.
  
  
  METHODS
  This study examined the accuracy of an ADP system modified for young children (BOD POD; Life Measurement, Concord, CA) by comparing %FM results from ADP with those obtained from TBW by deuterium (D(2)O) dilution (reference method) in 72 children aged 6-48 mo.
authors.affiliation: Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania, USA. rpr135@psu.edu
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Rosendale
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Bartok
mesh_terms: D001823:Body Composition; D001834:Body Water; D002675:Child, Preschool; D003903:Deuterium; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010991:Plethysmography / Q000379:methods*; D012044:Regression Analysis; D015203:Reproducibility of Results
chemical_list: D003903:Deuterium