Agreement Between Dual-Energy X-ray Absorptiometry and Bioelectric Impedance Analysis for Assessing Body Composition in Athletes: A Systematic Review and Meta-Analysis

Objective: To compare dual-energy x-ray absorptiometry (DXA) and bioelectric impedance analysis (BIA) in the assessment of body composition in athletes. Data Sources: A systematic review and meta-analysis was conducted collating peer-reviewed studies that compared BIA with DXA for the assessment of body composition in athletes that indexed in MEDLINE, CINAHL, EMBASE, and PsycINFO databases. Main Results: After duplicate removal, 267 articles remained for full-text screening. Sixtythree studies remained for the final inclusion, with 8 focused on athletes (n 5 461). Five studies were included in the meta-analysis and were rated as positive after risk of bias assessment, whereas the remaining were neutral. BIA overestimated fat-free mass (FFM) over DXA 2.78 (1.38-4.18) (mean difference 6 95% CI) with an effect size of 3.9(P , 0.001). Conclusions: BIA was found to overestimate total FFM when compared with DXA. Correlations are high between BIA and DXA; however, the limits of agreement are wide. Hence, BIA may not be a suitable substitute for DXA body composition scanning of athletes. Because of the low level of ionizing radiation exposure, the use of DXA should always be medically justified, and therefore, it is not recommended for repeat, measurements in