AIMS: To investigate the relationship between muscle size and density and bone mineral density (BMD) of the proximal femur in elderly men with hip fractures (HF) across different age groups. METHODS: Quantitative computed tomography (QCT) was conducted on the hip joints of 300 male patients with low-energy acute HF to measure areal BMD (aBMD). Concurrently, the cross-sectional area and density of the gluteal and thigh muscles surrounding the hip were assessed. Multivariable linear regression models were utilized to evaluate the associations between muscle characteristics and BMD across various age groups and fracture types. RESULTS: After adjusting for BMI covariates, all measures of aBMD in the femoral neck fracture (FNF) group were significantly positively correlated with mid-thigh muscle (MM) area in patients aged 75 years and older (P <
0.05). In contrast, thigh muscle density did not show a significant correlation. In patients younger than 75 years, there was a positive correlation between MM density and total hip (TH) aBMD in the FNF group (B, 9.077
95% CI, 1.577-16.577
P = 0.018). In the ITF group, no muscle parameters were found to be associated with aBMD. CONCLUSIONS: Our study demonstrated that in the FNF group aged 75 and older, thigh muscle size, but not density, was positively correlated with the BMD parameters of the proximal femur. Therefore, thigh muscle size may serve as a more clinically significant target for preventing FNF in older men.