Reduced leg muscle mass and lower grip strength in women are associated with osteoporotic vertebral compression fractures.

Abstract

We examined the relationship between bone mineral density, bone strength, skeletal muscle mass, grip strength, and skin autofluorescence (SAF) in women with osteoporotic vertebral compression fractures (VCF). A total of 1039 women (mean age 73.3 years) were included in our study. These included 222 cases of VCF (mean 77.8 years) and 817 controls (mean 72.0 years). Lumbar and femur BMD were measured for all participants using dual-energy X-ray absorptiometry (DXA). Bone strength surrogates, such as cross-sectional area (CSA) of the proximal femur, were evaluated using Advanced Hip Assessment software. SAF was measured with an autofluorescence reader. We used a bioelectrical impedance analyzer (BIA) to analyze body composition, including appendicular skeletal muscle mass index (SMI; appendicular lean mass (kg)/(height (m))2. We measured bone density, geometric parameters related to bone strength, skeletal muscle mass, grip strength, and SAF in both groups. We also examined factors related to vertebral fracture using multiple logistic regression analysis. Women with vertebral fractures had lower SMI (5.55 vs 5.76 kg/m2, p = 0.0006), smaller femoral cross-sectional area (97.20 vs 100.09, p = 0.014), lower grip strength (16.81 vs 19.16 kg, p < 0.0001), and increased skin autofluorescence (2.38 vs 2.25, p = 0.0002) compared to women without fractures. The prevalence of sarcopenia (SMI < 5.75) was 63.51% in VCF subjects and 52.02% in controls, revealing a high prevalence in VCF (p = 0.002). Skeletal muscle mass and grip strength were not significantly different between patients with acute and old VCF, suggesting that low skeletal muscle mass and muscle weakness may exist before fracture. From the multiple logistic regression analysis, lower femoral density (p = 0.0021), CSA (p = 0.0166), leg muscle mass (p = 0.0127), and left arm grip strength (p = 0.0255) were risk factors for vertebral compression fractures; all were negatively correlated with increased vertebral fractures. Lower limb muscle mass and grip loss may be closely related to the onset of vertebral compression fracture.