title: Total-body skeletal muscle mass: estimation by dual-energy X-ray absorptiometry in children and adolescents.
abstract: BACKGROUND
  Skeletal muscle (SM) is an important compartment but is difficult to quantify in children and adolescents.
  
  
  OBJECTIVE
  We investigated the potential of dual-energy X-ray absorptiometry (DXA) for measuring total-body SM in pediatric subjects.
  
  
  METHODS
  A previously published adult DXA SM prediction formula was evaluated in children and adolescents aged 5-17 y (n = 99) who varied in pubertal maturation stage. SM estimated by whole-body magnetic resonance imaging (MRI) was used as the reference. The adult SM model was not accurate for subjects below Tanner stage 5 (n = 65; aged 5-14 y). New pediatric SM prediction models were therefore developed and validated in a separate group (n = 18).
  
  
  RESULTS
  The adult DXA SM prediction model was valid in subjects at Tanner stage 5 but significantly (P < 0.001) overestimated SM in subjects below Tanner stage 5. New SM prediction formulas were developed with appendicular lean soft tissue (ALST) estimates by DXA as the main predictor variable (eg, model 1, ALST alone: R(2) = 0.982, SEE = 0.565 kg, P < 0.001). The new models were validated by the leave-one-out method and were cross-validated in a separate validation group.
  
  
  CONCLUSIONS
  A previously reported adult DXA SM prediction model is applicable in children and adolescents late in pubertal development (Tanner stage 5). A new DXA SM prediction model was developed for prepubertal and pubertal subjects (Tanner stage </=4) aged >/=5 y. DXA thus provides an important opportunity for quantifying total-body SM mass across most of the human life span.
authors.affiliation: Obesity Research Center, St Luke's-Roosevelt Hospital, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
authors.forename: Jaehee
authors.initials: J
authors.lastname: Kim
authors.forename: Wei
authors.initials: W
authors.lastname: Shen
authors.forename: Dympna
authors.initials: D
authors.lastname: Gallagher
authors.forename: Alfredo
authors.initials: A
authors.lastname: Jones
authors.forename: Zimian
authors.initials: Z
authors.lastname: Wang
authors.forename: Jack
authors.initials: J
authors.lastname: Wang
authors.forename: Stanley
authors.initials: S
authors.lastname: Heshka
authors.forename: Steven B
authors.initials: SB
authors.lastname: Heymsfield
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods* / Q000592:standards*; D000293:Adolescent; D001823:Body Composition / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006128:Growth / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000502:physiology*; D011237:Predictive Value of Tests; D011627:Puberty / Q000502:physiology*; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity