Appendicular Skeletal Muscle Mass-to-Visceral Fat Area Ratio and Bone Mineral Density in Type 2 Diabetes: A...

Bone fragility is common in type 2 diabetes mellitus (T2DM), but body mass index alone does not capture the balance between appendicular muscle and visceral adiposity. This retrospective cross-sectional study examined the association between the appendicular skeletal muscle mass-to-visceral fat area ratio (SVR) and bone mineral density (BMD) in hospitalized adults with T2DM. A total of 2,820 records were included in descriptive analyses, and 2,798 records with complete BMD endpoints and Model 5 covariates were included in regression analyses. Appendicular skeletal muscle mass and visceral fat area were obtained using multifrequency bioelectrical impedance analysis, whereas lumbar spine, femoral neck, and total hip BMD were measured by dual-energy X-ray absorptiometry. In fully adjusted linear models, each 1-SD increase in SVR was associated with higher lumbar spine BMD (0.017 g/cm²; 95% CI, 0.007-0.027; P = 0.001), femoral neck BMD (0.027 g/cm²; 95% CI, 0.019-0.035; P < 0.001), and total hip BMD (0.028 g/cm²; 95% CI, 0.020-0.036; P < 0.001). Sex-specific tertile plots did not reproduce the monotonic pattern seen with global tertiles, which were strongly sex-imbalanced. Natural cubic-spline models detected nonlinearity at all three sites (all P for nonlinearity < 0.001), with increasing predicted BMD that flattened at higher SVR values. HC3-robust confidence intervals were similar to the primary estimates. These findings describe cross-sectional conditional associations and do not establish causality, bone strength, fracture prediction, or a clinical SVR threshold.