Phase Angle Reflects Loss of Functionality in Older Women

This study verified if the phase angle (PA) formed by the resistance (R) and reactance (Xc) obtained from bioimpedance (BIA) might be a useful tool to identify functionality.

It was conducted a cross-sectional study with 152 women ≥ 65 years old from the community.

weight, height, body mass index (BMI), calf circumference (CC), hand grip strength (HGS), gait speed (GS), fat free mass (FFM), body fat (BF), PA with R and Xc from the BIA were measured. Spearman's and Pearson's correlations and the odds ratio (OR) were performed using the IBM SPSS software version 22.0.

Sixty-four percent (n=98) women are with PA below the reference. Negative moderate significant correlation was found between PA and age (r =- 0.440*; p<0.001). Moderate significant correlation was observed between PA and GS (r = 0.484**; p<0.001). Weak significant correlation was found between PA and HGS (r = 0.177*; p = 0.029). Odds ratio (OR) demonstrated that individuals with PA above the mean value have 4.77 times more chances of having increased GS (confidence interval 2.40-9.48; 95%). Women aged below the mean value have 4.02 times more chances of having higher PA (confidence interval 2.02-7.99; 95%). Younger aged women showed 4.02 times more chances of having higher PA (confidence interval 2.02-7.99; 95%).

Phase angle can be associated with functional tests, such as gait speed and hand grip strength, in older women.