title: Measurement of percentage of body fat in 411 children and adolescents: a comparison of dual-energy X-ray absorptiometry with a four-compartment model.
abstract: OBJECTIVE
  Pediatricians are encountering body composition information more frequently, with percentage of body fat (%BF) measurement receiving particular attention as a result of the obesity epidemic. One confounding issue is that different methods may yield different %BF results in the same person. The objective of this study was to compare dual-energy X-ray absorptiometry (DXA) with the criterion 4-compartment model (4-CM) for measurement of %BF in a large pediatric cohort and to assist pediatricians in appropriate interpretation of body composition information by recognizing differences between techniques.
  
  
  METHODS
  Height, weight, anthropometrics, body density by underwater weighing, total body water by deuterium dilution, and bone mineral content and %BF by DXA (Lunar DPX/DPX-L) were measured in 411 healthy subjects, aged 6 to 18 years. Values for %BF by 4-CM and DXA were compared using regression analysis.
  
  
  RESULTS
  The mean +/- standard deviation values for %BF by DXA (22.73% +/- 11.23%) and by 4-CM (21.72% +/- 9.42%) were different, but there was a strong relationship between the 2 methods (R2 = 0.85). DXA underestimated %BF in subjects with lower %BF and overestimated it in those with higher %BF. The relationship between the 2 methods was not affected by gender, age, ethnicity, pubertal stage, height, weight, or body mass index. The standard error of the estimate was 3.66%.
  
  
  CONCLUSIONS
  This analysis demonstrates a predictable relationship between DXA and 4-CM for %BF measurement. Because of its ease of use, consistent relationship with 4-CM, and availability, we propose that DXA has the capacity for clinical application including prediction of metabolic abnormalities associated with excess %BF in pediatrics.
authors.affiliation: Institute of Human Nutrition, Columbia University, New York, New York, USA.
authors.forename: Aviva B
authors.initials: AB
authors.lastname: Sopher
authors.forename: John C
authors.initials: JC
authors.lastname: Thornton
authors.forename: Jack
authors.initials: J
authors.lastname: Wang
authors.forename: Richard N
authors.initials: RN
authors.lastname: Pierson
authors.forename: Steven B
authors.initials: SB
authors.lastname: Heymsfield
authors.forename: Mary
authors.initials: M
authors.lastname: Horlick
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000886:Anthropometry / Q000379:methods*; D001823:Body Composition; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000175:diagnosis*