Proportional bias of multifrequency bioimpedance analysis is larger in Hispanic females than males.

Body composition algorithms are typically validated using multiethnic populations without accounting for ethnicity. This might be problematic when using multifrequency bioimpedance analysis (MF-BIA) for Hispanics. Group error (i.e., constant error [CE]), individual error (i.e., 95% limits of agreement [LOAs]), and proportional bias of MF-BIA were determined in Hispanic men and women (n = 84 and 97, respectively) when using dual energy X-ray absorptiometry (DXA) as a reference method. Because of the lack of an ethnic-specific impedance equation for Hispanics, it was hypothesized that MF-BIA would be biased when compared with DXA. For body fat percent, MF-BIA displayed similar CE ± 95% LOA for the sample (-3.17 ± 5.45%), males (-3.2 ± 5.5%), and females (-3.2 ± 5.4%) compared with DXA. However, moderate proportional bias was present for females (r = 0.48). The sample (r = 0.22) and males (r = -0.04) had trivial to no-proportional bias. Regarding fat mass, MF-BIA exhibited CE ± 95% LOA values of -1.4 ± 4.2 kg for the sample, -1.9 ± 4.6 kg for males, and -0.9 ± 3.6 kg for females. There was strong proportional bias for females (0.68) and moderate bias for the sample (r = 0.36). No proportional bias was observed for males (r = -0.02). For fat-free mass, males demonstrated the largest CE ± 95% LOA (1.6 ± 4.6), compared with the sample (1.2 ± 3.9 kg) and females (0.9 ± 3.4 kg) when MF-BIA was compared with DXA. No proportional biases existed for the sample (r = -0.01) or males (r = -0.10). However, females exhibited a moderate, negative bias (r = -0.38). Because of the observed moderate-to-strong proportional biases within body composition estimates, the need for ethnic-specific algorithms is warranted, particularly for the Hispanic female population.