How is the phase angle associated with total and regional bone mineral density in university athletes?

Objective.To investigate how phase angle (PhA) is associated with total and regional bone mineral density (BMD) (femur and lumbar spine) in university athletes.Approach.This cross-sectional study was conducted in Florianópolis, Brazil, with 167 university athletes from different sports (92 males). The PhA was obtained through electrical bioimpedance and BMD was obtained through dual x-ray absorptiometry (DXA). Data on the covariables age, time involved in the sport, type of sport (low, medium and high impact), daily use of oral contraceptives, and vitamin D calcium and/or protein supplementation were obtained through anamnesis, while fat mass and fat- and bone-free mass were obtained through DXA. Simple linear regression and a 5% significance level were used.Main results. In female athletes, PhA was directly associated with total BMD (β: 2.20; 95% CI: 0.43; 3.96) and BMD in the femur (β0.85; 95% CI: -0.23; 1.94) and lumbar spine (β: 1.45; 95% CI: 0.44; 2.46), even after adjusting for the covariates. In male athletes, although PhA was directly associated with regional BMD (femur [β: 0.63; 95% CI: 0.04; 1.22] and lumbar spine [β: 0.64; 95% CI: -0.01; 1.31]) in simple linear regression, this association disappeared when the covariates were added.Significance. PhA was directly associated with total BMD and lumbar spine in female, but not male, athletes.