Gender-influenced association between thyroid hormone sensitivity and body composition in euthyroid type 2 diabetes

Abstract

Abstract Background Impaired thyroid hormone sensitivity has been associated with type 2 diabetes (T2D), obesity, and metabolic syndrome, which can lead to alterations of body composition. However, impaired thyroid sensitivity to exacerbate alterations of body composition remains unconfirmed. This study aimed to ascertain impaired thyroid hormone sensitivity association with body composition in euthyroid T2D. Methods A total of 634 individuals with normothyroid T2D were enrolled. Each participant underwent a dual-energy X-ray absorptiometry (DXA) scan to assess body composition, including measurements of body fat percentage (B-FAT), trunk fat percentage (T-FAT), appendicular skeletal muscle index (ASMI), lumbar spine bone mineral density (BMD) (LS-BMD), femoral neck BMD (FN-BMD), hip BMD (H-BMD), and total BMD (T-BMD). Thyroid hormone resistance indices were assessed by calculating serum thyrotropin (TSH) index (TSHI), thyrotrophin T4 resistance index (TT4RI), thyroid feedback quantile-based index (TFQI), and parametric TFQI (PTFQI). Relevant clinical data was also collected. Results Among the recruited patients, females (n = 265) had higher indicators of thyroid hormone resistance and fat distribution than males (n = 369) (all P < 0.05). Across the entire population, indicators of thyroid hormone resistance exhibited positive correlations with fat distribution (all P < 0.01), while most indicators displayed negative associations with skeletal muscle mass. These findings were consistent solely among male participants. Furthermore, even after adjusting for basic characteristics, linear regression analysis revealed that these correlations remained statistically significant (all P < 0.05). Conclusions In males with euthyroid T2D, impaired thyroid hormone sensitivity correlates with fat distribution independent of conventional risk factors.