Lower-limb and whole-body tissue composition assessment in healthy active older women

Aim: The study evaluated, in active elderly women, the accuracy and bias of anthropometry and bioelectrical impedance analysis (BIA) for lower-limb and whole-body tissue composition measures using dual-energy X-ray absorptiometry (DXA) as the criterion method. Methods: Nineteen individuals (66.1 +/- 4.2 years) participated in the study. Whole-body fat mass ( FM) and fat-free mass (FFM) were measured by anthropometry, BIA and DXA. Lower-limb volume (LLV) and lower-limb FFM (LLFFM) were assessed by anthropometry and DXA. Results: LLV and LLFFM were significantly overestimated by anthropometry vs. DXA ( p< 0.05 and p< 0.001, respectively) but significant relationships were observed [ coefficient of determination (R(2))> 0.25, p< 0.05]. No significant difference was observed between FM(A) ( where (A) stands for anthropometry) vs. FM DXA and FFM A vs. FFM DXA and significant relationships were observed [R(2) = 0.93, p< 0.001, coefficient of variation ( CV) 7.3%; and R(2) = 0.85, p< 0.001, CV = 4.4%, respectively]. No significant difference was observed between FM BIA and FM DXA and a significant relationship was observed (R(2) = 0.80, p< 0.001, CV = 11.6%). FFM was significantly underestimated by BIA vs. DXA ( p< 0.01). Conclusions: In active elderly women, (i) compared with DXA, anthropometry overestimates LLV and LLFFM; (ii) anthropometry can be an accurate method for assessing whole-body composition; and (iii) despite a non-significant bias for the FM measurement, the BIA tends to overestimate FM and underestimate FFM.