Sex-Specific Associations Among Phase Angle, Bone Strength, And Handgrip Strength In Healthy Young Adults

Phase angle (PhA) is known to be an indicator of cellular integrity and quality, which has been associated with various health outcomes in clinical populations. However, little is known regarding sex-specific relationships between PhA and bone strength, measured by quantitative ultrasound and handgrip strength in healthy young adults. PURPOSE: The aim of this cross-sectional study was to determine whether bioelectrical impedance-derived PhA was related to bone strength and handgrip strength. METHODS: Healthy young women (n = 70, 21.1 ± 1.8 years, 163.5 ± 5.7 cm, 64.1 ± 10.6 kg) and men (n = 50, 21.0 ± 1.8 years, 177.5 ± 8.5 cm, 81.9 ± 14.7 kg) between 18 and 25 years were recruited from Rowan University. The PhA and body composition were estimated by bioelectrical impedance analysis. Isometric handgrip strength (HGS in kg) was measured by dynamometer, and the average of three trials of the non-dominant side was used for data analysis. We measured the quantitative ultrasound-assessed speed of sound (SOS in m/s) at one-third distal radius of the nondominant hand and midshaft tibia of the nondominant leg. RESULTS: Student’s t-tests revealed that young men had greater PhA (6.9° vs. 5.7°) and HGS (36.2 kg vs. 21.9 kg) than young women (p < 0.001). Young women had greater radius SOS (4122 m/s vs. 4043) than young men (p < 0.001), but no sex difference was found in midshaft tibia (p < 0.05). Pearson’s correlations indicated that there were negative associations between PhA and radius/tibia SOS in the whole cohort (Radius, r = -.251, p = 0.006; Tibia, r = -.219, p = 0.017). The PhA was positively correlated with HGS in young women (r = .270, p = 0.024) while no significant relationship was found in young men (r = .157, p = 0.277). CONCLUSIONS: PhA might be used as a predictor of muscle strength in healthy young women. Our study provides preliminary evidence of negative relationships of PhA with bone strength measures at radius and tibia sites.