The relationship between osteoporosis and sarcopenia parameters in postmenopausal women under 60 years of age: A cross-sectional study.

Objective: This study aimed to determine the prevalence of sarcopenia in postmenopausal women under the age of 60 and to evaluate the relationship between sarcopenia, bone mineral density (BMD), and clinical parameters.

Materials and methods: This cross-sectional study included 52 postmenopausal women under the age of 60, classified as osteoporotic or non-osteoporotic based on DXA results. Sarcopenia was assessed using the criteria of the European Working Group on Sarcopenia in Older People (EWGSOP2). Muscle strength was measured using handgrip strength and the five-time sit-to-stand test (5STS), and muscle mass was assessed with the Tanita BC-418MA device. Skeletal muscle mass indices (SMMI) were calculated based on height², weight, and BMI.

Results: Fat-free mass (FFM), skeletal muscle mass (SMM), and SMM/height² values were significantly lower in the osteoporotic group compared to the non-osteoporotic group (p < 0.05). No significant differences were found between the groups in handgrip strength or 5STS results. Sarcopenia prevalence varied depending on the muscle index used: 17.3% based on SMM/BMI (23.1% in the osteoporotic group, 11.5% in the non-osteoporotic group), 11.5% based on SMM/weight (3.8% vs. 19.2%), and 3.8% based on SMM/height² (equal in both groups). These differences were not statistically significant (p > 0.05). Femoral neck and lumbar BMD and T-scores showed positive correlations with FFM and SMM, but not with muscle strength tests.

Conclusion: In our study, sarcopenia prevalence did not significantly differ between osteoporotic and non-osteoporotic postmenopausal women under 60. However, the lower muscle mass observed in the osteoporotic group may indicate early structural changes associated with sarcopenia. The lack of difference in functional capacity suggests that these changes may not yet be clinically apparent.