title: Validity of six field and laboratory methods for measurement of body composition in boys.
abstract: OBJECTIVE
  To determine the validity of the following six body composition methods against a reference method (three-component model): air displacement plethysmography (BODPOD); estimation from body density using BODPOD; skinfold thickness using the Slaughter equations; bioelectrical impedance, both leg-leg (TANITA) and hand-foot (Bodystat) approaches; and total body water.
  
  
  METHODS
  Forty-two healthy white 10- to 14-year-old boys (mean age, 12.9 +/- 1.0 years) were enrolled in this study. Measures of body fat percentage and body fat mass derived from the three-component model were used as the reference method. Validity of all of the other methods was assessed by comparison against the reference by calculation of biases and limits of agreement.
  
  
  RESULTS
  Mean body fatness measured using the reference method was 16.4 +/- 11.6% and 8.7 +/- 7.0 kg. Estimates of fatness from total body water had the narrowest limits of agreement relative to the reference (+0.9 +/- 5.0% body fat; +0.5 +/- 2.9 kg fat mass). For all other methods tested, we observed large biases and very wide limits of agreement.
  
  
  CONCLUSIONS
  This study suggests that the validity of newer field and laboratory methods for estimation of body composition is poor in adolescent boys. For applications where high accuracy of estimation at the individual level is essential, only reference methods would be acceptable.
authors.affiliation: Centre for Exercise Science and Medicine, West Medical Building, University of Glasgow, Glasgow, Scotland.
authors.forename: Lisa
authors.initials: L
authors.lastname: Parker
authors.forename: John J
authors.initials: JJ
authors.lastname: Reilly
authors.forename: Christine
authors.initials: C
authors.lastname: Slater
authors.forename: Jonathan C K
authors.initials: JC
authors.lastname: Wells
authors.forename: Yannis
authors.initials: Y
authors.lastname: Pitsiladis
mesh_terms: D000293:Adolescent; D001823:Body Composition; D015992:Body Mass Index; D001834:Body Water; D002648:Child; D017097:Electric Impedance; D006801:Humans; D008297:Male; D010991:Plethysmography / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012885:Skinfold Thickness