Agreement between multifrequency BIA and DXA for assessing segmental appendicular skeletal muscle mass in older adults

Background Aging presents changes in muscle mass that may lead to sarcopenia. Identifying safe, quick, and accessible methods to assess muscle mass is imperative. Aims The purpose of this investigation was to compare the assessments of appendicular skeletal muscle mass (ASMM), fat-free mass (FFM), and fat mass (FM) between bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA). Methods Seventy-three healthy, community-dwelling, physically active males (n = 19) and females (n = 54) (BMI = 27.1 +/- 4.3 kg m(-2)) between the ages of 55-85 years underwent total-body BIA and DXA. ASMM was estimated via BIA from a previously published regression equation while DXA ASMM was calculated as the sum of the measured total arm lean mass and total leg lean mass. Paired-samples t tests with a significance level of p < 0.05 were conducted, while agreement between the methods was assessed via Bland-Altman plots. Results In comparison to DXA, the chosen BIA equation overestimated ASMM (21.61 +/- 5.82 kg vs. 18.82 +/- 4.81 kg) and FFM (49.57 +/- 9.94 kg vs. 46.22 +/- 10.11 kg) and underestimated FM (24.59 +/- 8.28 kg vs. 27.13 +/- 10.01 kg), all p < 0.001. Visual inspection of the Bland-Altman plots revealed wide limits of agreement. Female participants were more clustered around the mean than male participants. Discussion The multifrequency BIA device and chosen ASMM estimation equation resulted in wide limits of agreement and significantly different comparisons to the reference method of DXA. Conclusion Future research should continue to investigate and validate methodologies to screen older individuals for characteristics of aging-related diseases, such as sarcopenia.