Phase angle can predict bone indicators in older adults: a cross-sectional study

Abstract

Osteoporosis is considered a worldwide public health concern, which is characterized by low bone mass and microarchitectural changes in the bone being a risk factor for fractures in older adults. This study aimed to verify a relationship between phase angle (PhA) with bone indicators. We also intended to analyse the ability of PhA to predict bone indicators after adjusting for potential confounders. This cross-sectional study included fifty-six physically independent older adults (age, 70.57 ± 3.79 years; BMI, 28.09 ± 4.37 kg/m2). Bioelectrical impedance analysis was used to measure PhA at 50 KHz. Additionally, bone indicators represented by bone mineral density (BMD) and bone mineral content (BMC) for whole-body and dominant femoral neck were measured through dual-energy X-ray absorptiometry. The University of Évora Ethics Committee approved this study (approval no. 22030). There were moderate associations between PhA and whole-body BMC (p= 0.019; r= 0.316), femoral neck BMC (p< 0.01; r= 0.469), and femoral neck BMD (p= 0.006; r= 0.365). In addition, after adjusting for potential confounders the linear regression analysis verified that PhA was a significant predictor of bone indicators: whole-body BMC, β= 1803.659; p< 0.01; R2= 0.523; femoral neck BMC, β= -1.367; p= 0.001; R2= 0.212; and femoral neck BMD, β= 0.179; p= 0.022; R2= 0.120). Good levels of bone indicators, particularly femoral neck BMD and BMC are related with higher cellularity, cell membrane integrity and better cell function, expressed by PhA. We also conclude that the PhA can be used as a marker of bone quality.