title: Associations between pQCT-based fat and muscle area and density and DXA-based total and leg soft tissue mass in healthy women and men.
abstract: Peripheral Quantitative Computed Tomography (pQCT) can be used for muscle and fat area and density assessments. These may independently influence muscle and fat mass measurements from Dual Energy X-ray Absorptiometry (DXA).
  
  
  OBJECTIVE
  To determine associations between pQCT-derived soft tissue density and area measures and DXA-derived soft tissue mass.
  
  
  METHODS
  Linear regression models were developed based on BMI and calf fat and muscle cross-sectional area (FCSA and MCSA) and density measured by pQCT in healthy women (n=76) and men (n=82) aged 20-59 years. Independent variables for these models were leg and total bone-free lean mass (BFLM) and fat mass (FM) measured by DXA.
  
  
  RESULTS
  Sex differences (p<0.01) were found in both muscle (Mean±SE: Women: 78.6±0.4; Men: 79.9±0.2 mg/cm(3)) and fat (Women: 0.8±0.4 Men: 9.1±0.6 mg/cm(3)) density. BMI, fat density, and age (R(2)=0.86, p<0.01) best accounted for the variability in total FM. FCSA, BMI, and fat density explained the variance in leg FM (R(2)=0.87, p<0.01). MCSA and muscle density explained the variance in total (R(2)=0.65, p<0.01) and leg BFLM (R(2)=0.70, p<0.01).
  
  
  CONCLUSIONS
  Calf muscle and fat area and density independently predict lean and fat tissue mass.
authors.affiliation: University of Colorado Anschutz Medical Campus, Division of Geriatric Medicine.
authors.forename: V D
authors.initials: VD
authors.lastname: Sherk
authors.forename: R S
authors.initials: RS
authors.lastname: Thiebaud
authors.forename: Z
authors.initials: Z
authors.lastname: Chen
authors.forename: M
authors.initials: M
authors.lastname: Karabulut
authors.forename: S J
authors.initials: SJ
authors.lastname: Kim
authors.forename: D A
authors.initials: DA
authors.lastname: Bemben
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D001823:Body Composition; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007866:Leg / Q000033:anatomy & histology*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000033:anatomy & histology*; D012727:Sex Characteristics; D014057:Tomography, X-Ray Computed; D055815:Young Adult