title: Use of conventional regional DXA scans for estimating whole body composition.
abstract: BACKGROUND
  Using soft-tissue composition in conventional regional dual-energy X-ray absorptiometry (DXA) scans of the spine and hip to predict whole body composition (whole-body fat mass, whole-body lean mass and trunk-fat mass) instead of a whole body DXA scan.
  
  
  METHODS
  We identiﬁed 143 adult patients who underwent DXA evaluation of the whole body. Anthropometric indices were also measured. Datasets were split randomly into two parts; the derivation set including a sample of 100 subjects, and the validation set including a sample of 43 subjects. Multiple regression analysis with the backward stepwise elimination procedure was used for the derivation set and the estimates were then compared with the actual measurements from the whole-body scans for the validation set. The Ra2 (adjusted coefficient of multiple determination) and SSE (error sum of squares) criteria were applied to compare regression models.
  
  
  RESULTS
  Using multiple linear regression analyses, the best equation for predicting whole-body fat mass (Ra2= 0. 945) included gender, height, weight, waist circumference (WC), spine fat fraction and hip fat fraction; the best equation for predicting whole-body lean mass (Ra2 = 0. 970) included gender, weight, WC, spine fat fraction and hip fat fraction; and the best equation for predicting trunk-fat mass (Ra2 = 0. 944) included gender, weight, spine fat fraction and hip fat fraction.
  
  
  CONCLUSIONS
  The results of this study show that regional DXA scans of the spine and hip can be used to accurately predict body composition.
authors.affiliation: 1)Biosensor Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.2)Assistant Professor, Department of Medical Physics and Medical Engineering, Medical School, Isfahan University of Medical Sciences, Isfahan, Iran. 4)Department of Research and Development Isfahan Osteoporosis Diagnosis and Body Composision Center, Isfahan, Iran.m.mahdiasgari@yahoo.com.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Salamat
authors.affiliation: Assistant Professor, Department of Medical Physics and Medical Engineering, Medical School, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Shanei
authors.affiliation: Department of Biostatistics and Epidemiology, Health School, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mehri
authors.initials: M
authors.lastname: Khoshhali
authors.affiliation: Department of Research and Development, Isfahan Osteoporosis Diagnosis and Body Composition Center, Isfahan, Iran.
authors.forename: Amir Hossein
authors.initials: AH
authors.lastname: Salamat
authors.affiliation: Assistant Professor, Department of Endocrinology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mansour
authors.initials: M
authors.lastname: Siavash
authors.affiliation: Department of Medical Physics and Medical Engineering, Medical School, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Asgari
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000000981:diagnostic imaging; D000367:Age Factors; D001823:Body Composition; D003430:Cross-Sectional Studies; D005260:Female; D006615:Hip / Q000000981:diagnostic imaging; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D013131:Spine / Q000000981:diagnostic imaging