The relationship between body morphology, handgrip strength, and bone mineral density in Chinese college students: the mediating role of skeletal muscle

Background Adolescence is a critical period for bone mineral density (BMD) accumulation. However, the relationship between body morphology, handgrip strength (HGS), and BMD, as well as the mediating mechanisms involved, remains unclear among Chinese college students. Objective To conduct an in-depth analysis of the mediating effect of skeletal muscle (the measured variable is skeletal muscle mass) on the relationship between body morphology, HGS, and BMD in Chinese college students, and to reveal the underlying mechanisms influencing human BMD. Methods A random cluster sampling method was used to select 104 Chinese college students from a regular institution of higher education as cross-sectional study participants. Pearson correlation analysis and structural equation modeling were employed for data processing to construct a relationship model among height, weight, HGS, skeletal muscle, and BMD of the distal radius and ulna in the left forearm. Results The Pearson correlation coefficients between height, weight, HGS, distal radius and ulna BMD, and skeletal muscle were 0.769, 0.795, 0.872, and 0.498, respectively ( p < 0.05). After controlling for sex, skeletal muscle played a significant mediating role in the relationships between weight, HGS, and distal radius and ulna BMD among Chinese college students ( p < 0.05), with mediating effect values of 0.293, and 0.238, respectively. Sex directly predicted skeletal muscle ( p < 0.001) with effect values of 0.229, but not BMD ( p = 0.056). Conclusion Skeletal muscle plays a significant mediating role in the relationships between weight, HGS, and BMD in Chinese college students. Height does not indirectly influence BMD through skeletal muscle after controlling for sex. Increasing skeletal muscle mass remains an effective approach for enhancing BMD, particularly by maintaining adequate weight and grip strength.