Gynoid lean muscle mass as mediator between menarche age, hand grip and bone mineral density in postmenopausal women

Numerous clinical studies indicate that reproductive factors and physical performance levels are significant predictors of bone mineral density (BMD) in postmenopausal women. However, research on the relationship between these factors and body composition remains limited, and the mediating role of body composition in the impact of these factors on BMD remains unclear. This cross-sectional study aims to explore the correlation between reproductive factors, physical performance levels, BMD, and body composition in postmenopausal women, and to further investigate the mediating role of body composition in these relationships. This study enrolled 102 postmenopausal women meeting predetermined criteria from the osteoporosis outpatient clinic of Huzhou Central Hospital, China. Data were collected through surveys, assessments of physical performance function, and dual-energy X-ray absorptiometry (DXA) measurements. Correlation analysis and multiple linear regression analysis were used to determine the relationships among factors. Mediation analysis was conducted to explore the mediating role of body composition, followed by logistic regression analysis to investigate risk factors for osteoporosis. Gynoid Lean Muscle Mass (GLM) emerged as an independent predictive factor for BMD of spine, hip, and total body, and a protective factor against osteoporosis. Hand grip and 6-meter gait speed were positively correlated with BMD at these skeletal sites and GLM, also serving as protective factors against osteoporosis. Conversely, menarche age and Time taken for 5 sit-ups exhibited negative correlations with BMD and GLM, concurrently representing risk factors for osteoporosis. GLM mediated the relationship between menarche age, hand grip, and hip BMD. Prolonged reproductive periods and enhanced physical performance appear beneficial in mitigating Lean Mass loss, particularly GLM, in postmenopausal women, thereby protecting BMD and effectively preventing osteoporosis.