title: Comparison of body composition methods in overweight and obese children.
abstract: The objective of the present study was to investigate the accuracy of percent body fat (%fat) estimates from dual-energy X-ray absorptiometry, air-displacement plethysmography (ADP), and total body water (TBW) against a criterion four-compartment (4C) model in overweight and obese children. A volunteer sample of 30 children (18 male and 12 female), age of (mean +/- SD) 14.10 +/- 1.83 yr, body mass index of 31.6 +/- 5.5 kg/m, and %fat (4C model) of 41.2 +/- 8.2%, was assessed. Body density measurements were converted to %fat estimates by using the general equation of Siri (ADPSiri) (Siri WE. Techniques for Measuring Body Composition. 1961) and the age- and gender-specific constants of Lohman (ADPLoh) (Lohman TG. Exercise and Sport Sciences Reviews. 1986). TBW measurements were converted to %fat estimates by assuming that water accounts for 73% of fat-free mass (TBW73) and by utilizing the age- and gender-specific water contents of Lohman (TBWLoh). All estimates of %fat were highly correlated with those of the 4C model (r > or = 0.95, P < 0.001; SE < or = 2.14). For %fat, the total error and mean difference +/- 95% limits of agreement compared with the 4C model were 2.50, 1.8 +/- 3.5 (ADPSiri); 1.82, -0.04 +/- 3.6 (ADPLoh); 2.86, -2.0 +/- 4.1 (TBW73); 1.90, -0.3 +/- 3.8 (TBWLoh); and 2.74, 1.9 +/- 4.0 DXA (dual-energy X-ray absorptiometry), respectively. In conclusion, in overweight and obese children, ADPLoh and TBWLoh were the most accurate methods of measuring %fat compared with a 4C model. However, all methods under consideration produced similar limits of agreement.
authors.affiliation: School of Leisure and Sport, Leeds Metropolitan University, Leeds LS6 3QS, United Kingdom. p.gately@lmu.ac.uk
authors.forename: P J
authors.initials: PJ
authors.lastname: Gately
authors.forename: D
authors.initials: D
authors.lastname: Radley
authors.forename: C B
authors.initials: CB
authors.lastname: Cooke
authors.forename: S
authors.initials: S
authors.lastname: Carroll
authors.forename: B
authors.initials: B
authors.lastname: Oldroyd
authors.forename: J G
authors.initials: JG
authors.lastname: Truscott
authors.forename: W A
authors.initials: WA
authors.lastname: Coward
authors.forename: A
authors.initials: A
authors.lastname: Wright
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods* / Q000592:standards; D000293:Adolescent; D001823:Body Composition; D001825:Body Fluid Compartments; D001834:Body Water; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000000981:diagnostic imaging* / Q000473:pathology*; D010991:Plethysmography / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results