| Objective To evaluate the correlation between muscle content index and bone mineral density (BMD) of different parts, and to screen the best site of muscle content index measurement and cut-off point for predicting the risk of postmenopausal osteoporosis. Methods A total of 1366 postmenopausal women were selected from the Health Management Center of the Affiliated Hospital of Guizhou Medical University from January 2018 to October 2021. BMD and skeletal muscle content (ASM) of limbs were measured with DXA and BIA methods. Muscle indexes such as ASMI, ASMBMI, and SMI were calculated from ASM. ROC curve and logistic regression analysis were used to verify the ability of muscle index to predict OP risk and to evaluate the correlation strength. Results The muscle content in OP group was lower than that in non-OP group. There was no significant difference between SMI and different BMD group in lumbar, the visceral fat area and different BMD group in femoral neck, and ASMBMI and different BMD group in greater trochanter and total hip BMD (P>0.05). There were significant differences in fat and muscle content among different BMD group (P<0.05). There was a negative correlation between BMD and SMI (r=0.095, -0.122, r=0.195 and r=0.177, P<0.05), and a positive correlation with ASM, ASM and ASMBMI (r=0.369, 0.298, 0.085/0.366, 0.297, 0.066/0.366, 0.362/0.362, 0.360, P<0.05). ROC curve and regression analysis showed that ASM<17.2 kg (OR=3.699) and ASMBMI<0.74 (OR=2.235) were the highest muscle content indexes and cut-off points for predicting the risk of OP in postmenopausal women. Conclusion ASM<17.2 kg and ASMBMI< 0.74 are independent risk factors of OP and muscle mass index and cut-off point range for predicting the risk of OP in postmenopausal women's femoral neck and lumbar spine. |