The complex impedance phase angle of dominant arm: a useful parameter in bone mineral density (BMD) assessment of...

For widespread osteoporosis (OP) screening, portable and cost-effective screening devices are needed. With 45 menopaused women, when body mass index was below 30 kg.m^- 2, the phase angle (PhA) of complex bioimpedance at 5 kHz, measured from the dominant arm, was correlated with dual-energy X-ray absorptiometry (DEXA) measured central bone mineral densities (BMD), for total hip r = 0.493 and for total lumbar r = 0.411, P< 0.05, and the strength of correlation decreased with increasing measurement frequencies. ANOVA tests showed that, below 15 kHz, PhA was a descriptive marker for bone mineral deficiency. By correlating to hip and lumbar bone mineral densities simultaneously, the dominant arm segment PhA was superior to the characteristic frequency f_c of the body impedance spectroscopy (BIS) and the PhA of whole-body impedance measurements, of the earlier research works. Due to its medium correlation strength with central BMDs, a PhA measuring device could be considered as a complementary tool to the gold standard (DEXA), for OP screening of group 1 post-menopausal women only. For group 2, with 44 subjects with body mass indices over 30 kg.m^- 2, i.e., obese population, the PhA was not correlated with BMD and was no longer a descriptive marker for reduced BMD.