title: Striking differences in estimates of infant adiposity by new and old DXA software, PEAPOD and skin-folds at 2 weeks and 1 year of life.
abstract: Infant adiposity better predicts childhood obesity/metabolic risk than weight, but technical challenges fuel controversy over the accuracy of adiposity estimates.
  
  
  
  We prospectively measured adiposity (%fat) in term newborns (NB) at 2 weeks (n = 41) and 1 year (n = 30).
  
  
  
  %fat was measured by dual X-ray absorptiometry (DXA), PEAPOD and skin-folds (SF). DXAs were analyzed using Hologic Apex software 3.2(DXAv1) and a new version 5.5.2(DXAv2).
  
  
  
  NB %fat by DXAv2 was 55% higher than DXAv1 (14.2% vs. 9.1%), 45% higher than SF (9.8%), and 36% higher than PEAPOD (10.4%). Among NB, Pearson correlations were 0.73-0.89, but agreement (intra-class correlations) poor between DXAv2 and DXAv1 (0.527), SF (0.354) and PEAPOD (0.618). At 1 year, %fat by DXAv2 was 51% higher than DXAv1 (33.6% vs. 22.4%), and twice as high compared with SF (14.6%). Agreement was poor between DXAv2 and DXAv1 (0.204), and SF (0.038). The absolute increase in %fat from 2 weeks to 1 year was 19.7% (DXAv2), 13.6% (DXAv1) and only 4.8% by SF.
  
  
  
  Analysis of the same DXA scans using new software yielded considerably higher adiposity estimates at birth and 1 year compared with the previous version. Using different modalities to assess body composition longitudinally is problematic. Standardization is gravely needed to determine how early life exposures affect childhood obesity/metabolic risk.
authors.affiliation: Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.|Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Barbour
authors.affiliation: Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.|College of Nursing, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Hernandez
authors.affiliation: Department of Pediatrics, Section of Neonatology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Reynolds
authors.affiliation: Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Reece
authors.affiliation: Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: C
authors.initials: C
authors.lastname: Chartier-Logan
authors.affiliation: Department Medicine, Division of Geriatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Anderson
authors.affiliation: Hologic, Inc, Bedford, MA, USA.
authors.forename: T
authors.initials: T
authors.lastname: Kelly
authors.affiliation: Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.|Department of Pediatrics, Section of Neonatology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Friedman
authors.affiliation: Department Medicine, Division of Geriatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Van Pelt
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000273:Adipose Tissue / Q000378:metabolism; D050154:Adiposity; D000886:Anthropometry; D001823:Body Composition; D001835:Body Weight; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D063766:Pediatric Obesity / Q000378:metabolism; D010991:Plethysmography / Q000379:methods*; D011446:Prospective Studies; D012984:Software
keywords: Air displacement plethysmography; anthropometry; childhood obesity risk; dual X-ray absorptiometry; infant body composition; intrauterine environment