The Relationship Between TPOAb and Osteoporosis: Moderating Effect Of Visceral-to-Subcutaneous Fat Area Ratio

Abstract: This cross-sectional study aimed to explore the relationship between thyroid peroxidase antibody (TPOAb) and osteoporosis, and the moderating effect of visceral-to-subcutaneous fat area ratio (VSR). A total of 128 males aged over 60 years with normal thyroid function and positive TPOAb (>9 IU/ml) were included. Lumbar spine, femoral neck, and whole-body bone mineral density (BMD) were measured by dual-energy X-ray absorptiometry. Visceral fat area (VFA) and subcutaneous fat area (SFA) were measured by the Omron DUALSCAN device. The relationships between TPOAb, VSR, interaction term (VSR*TPOAb) and BMD were analyzed using multiple linear regression models. Further subgroup analyses were performed stratified by VSR tertiles. TPOAb showed a significant negative correlation with BMD in the unadjusted model (p<0.01). However, when adjusted for confounding covariates, the correlation between TPOAb and BMD was no longer statistically significant (p>0.05). Further analysis showed VSR and the interaction term (VSR*TPOAb) were significantly negative associated with BMD in fully adjusted model (p<0.01). Subgroup analysis, stratified by VSR tertiles, showed that TPOAb only in T3 group (VSR>0.67) was negatively associated with lumbar spine and whole-body BMD (p<0.05). Hence, the relationship between TPOAb and BMD in elderly males varies with VSR. The abnormal body fat distribution may be a key moderator of the TPOAb-BMD relationship, suggesting the necessity for personalized bone health monitoring. Specifically, for patients with VSR>0.67, TPOAb screening is of great significance for the early prevention of osteoporosis.