Validation of fan beam dual energy x ray absorptiometry for body composition assessment in adults aged 18–45 years

• Published in: British journal of sports medicine Vol. 38; no. 4; pp. 472 - 476
• Main Authors: Norcross, J, Van Loan, M D
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine 01.08.2004; BMJ Publishing Group LTD; BMJ Publishing Group; BMJ Group
• Subjects: Absorptiometry, Photon - methods; Absorptiometry, Photon - standards; Adolescent; Adult; Analysis of Variance; BF; BFLM; BMC; BMD; Body composition; Body Composition - physiology; Body fat; bone free lean mass; bone mineral content; bone mineral density; Comparative analysis; dual energy x ray absorptiometry; DXA; Estimates; fan beam dual energy x ray absorptiometry; fat free mass; fat mass; Female; FFM; Humans; hydrostatic weighing; Investigations; Laboratories; Male; Measurement; Middle Aged; multicompartment model; Older people; Original; percentage body fat; Prodigies; TBW; total body water; Validation studies; X-rays; United States > US
• ISSN: 0306-3674; 1473-0480
• DOI: 10.1136/bjsm.2003.005413

Background: Pencil beam dual energy x ray absorptiometry (DXA) has been shown to provide valid estimates of body fat (%BF), but DXA fan beam technology has not been adequately tested to determine its validity. Objective: To compare %BF estimated from fan beam DXA with %BF determined using two and three compartment (2C, 3C) models. Methods: Men (n  =  25) and women (n  =  31), aged 18–41 years, participated in the study. Body density, from hydrostatic weighing, was used in the 2C estimate of %BF; DXA was used to determine bone mineral content (BMC) for the 3C estimate of %BF calculated using body density and BMC (3CBMC). DXA was also used to determine %BF. Analysis of variance was used to test for significant differences in %BF between sexes and among methods. Results: Women were significantly shorter, weighed less, had less fat free mass, and a higher %BF than men. No significant differences were found among methods (2C, 3CBMC, DXA) for determination of %BF in either sex. Although not significant, Bland-Altman plots showed that DXA gave higher values for %BF than the 2C and 3CBMC methods. Conclusion: DXA determination of %BF was not different from that of the 2C and 3CBMC models in this group of young adults. However, to validate fan beam DXA fully as a method for body composition assessment in a wide range of individuals and populations, comparisons are needed that use a 4C model with a measure of total body water and BMC.