BACKGROUND: Dual-energy X-ray absorptiometry (DXA) is widely used to assess body composition in research and clinical practice. Several studies have evaluated its accuracy in healthy persons; however, little attention has been directed to the same issue in patients. OBJECTIVE: The objective was to compare the accuracy of the Lunar Prodigy DXA for body-composition analysis with that of the reference 4-component (4C) model in healthy subjects and in patients with 1 of 3 disease states. DESIGN: A total of 215 subjects aged 5.0-21.3 y (n = 122 healthy nonobese subjects, n = 55 obese patients, n = 26 cystic fibrosis patients, and n = 12 patients with glycogen storage disease). Fat mass (FM), fat-free mass (FFM), and weight were measured by DXA and the 4C model. RESULTS: The accuracy of DXA-measured body-composition outcomes differed significantly between groups. Factors independently predicting bias in weight, FM, FFM, and percentage body fat in multivariate models included age, sex, size, and disease state. Biases in FFM were not mirrored by equivalent opposite biases in FM because of confounding biases in weight. CONCLUSIONS: The bias of DXA varies according to the sex, size, fatness, and disease state of the subjects, which indicates that DXA is unreliable for patient case-control studies and for longitudinal studies of persons who undergo significant changes in nutritional status between measurements. A single correction factor cannot adjust for inconsistent biases.
BACKGROUND: Dual-energy X-ray absorptiometry (DXA) is widely used to assess body composition in research and clinical practice. Several studies have evaluated its accuracy in healthy persons; however, little attention has been directed to the same issue in patients. OBJECTIVE: The objective was to compare the accuracy of the Lunar Prodigy DXA for body-composition analysis with that of the reference 4-component (4C) model in healthy subjects and in patients with 1 of 3 disease states. DESIGN: A total of 215 subjects aged 5.0-21.3 y (n = 122 healthy nonobese subjects, n = 55 obesepatients, n = 26 cystic fibrosispatients, and n = 12 patients with glycogen storage disease). Fat mass (FM), fat-free mass (FFM), and weight were measured by DXA and the 4C model. RESULTS: The accuracy of DXA-measured body-composition outcomes differed significantly between groups. Factors independently predicting bias in weight, FM, FFM, and percentage body fat in multivariate models included age, sex, size, and disease state. Biases in FFM were not mirrored by equivalent opposite biases in FM because of confounding biases in weight. CONCLUSIONS: The bias of DXA varies according to the sex, size, fatness, and disease state of the subjects, which indicates that DXA is unreliable for patient case-control studies and for longitudinal studies of persons who undergo significant changes in nutritional status between measurements. A single correction factor cannot adjust for inconsistent biases.
Authors: Jordan R Moon; Joan M Eckerson; Sarah E Tobkin; Abbie E Smith; Christopher M Lockwood; Ashley A Walter; Joel T Cramer; Travis W Beck; Jeffrey R Stout Journal: Eur J Appl Physiol Date: 2008-10-21 Impact factor: 3.078
Authors: Paola Pisani; Maria Daniela Renna; Francesco Conversano; Ernesto Casciaro; Maurizio Muratore; Eugenio Quarta; Marco Di Paola; Sergio Casciaro Journal: World J Radiol Date: 2013-11-28
Authors: Dana L Duren; Richard J Sherwood; Stefan A Czerwinski; Miryoung Lee; Audrey C Choh; Roger M Siervogel; Wm Cameron Chumlea Journal: J Diabetes Sci Technol Date: 2008-11
Authors: J C K Wells; D Haroun; J E Williams; C Wilson; T Darch; R M Viner; S Eaton; M S Fewtrell Journal: Int J Obes (Lond) Date: 2010-01-12 Impact factor: 5.095