Associations of thyroid feedback quantile-based index with diabetes in euthyroid adults in the United States and China

We aimed to investigate the associations between thyroid hormone sensitivity indices and diabetes in euthyroid adults in the United States and China.2296 euthyroid adults from the NHANES in the United States and 8319 euthyroid adults from the SPEED-Shunde in China were involved. The thyroid sensitivity indices, namely TFQIFT4 and TFQIFT3, were calculated. Multivariable logistic regression, restricted cubic spline analysis, and general ordinal logit regression were utilized.In the NHANES, compared with participants in quartile 1st (Q1), those in Q4 of TFQIFT3 (OR 2.12, 95% CI (1.18, 3.81)) and those in Q3 of TFQIFT4 (OR 2.31, 95% CI (1.18, 4.53)) (both Pfor trend < 0.05) were associated with a greater prevalence of diabetes. In the SPEED-Shunde, compared with participants in Q1, those in Q4 of TFQIFT3 had a greater prevalence of diabetes (OR 1.36, 95% CI (1.11, 1.66) (Pfor trend < 0.05), while no significant associations between TFQIFT4 and diabetes were found.TFQIFT3 was associated with a higher prevalence of diabetes both in the United States and China. However, TFQIFT4 was only associated with a higher prevalence of diabetes in the United States, not in China. Further prospective cohort studies are necessary to validate these findings.