Association between central thyroid hormone sensitivity and prediabetes: Tehran thyroid study.

BACKGROUND

Thyroid hormone sensitivity indices represent a recently proposed clinical entity related to metabolic health outcomes. The link between thyroid hormone sensitivity and prediabetes is not clear. This population-based study investigated the association between thyroid hormone sensitivity indices and prediabetes.

METHODS

Among 5,783 participants over 20 years, after excluding those receiving thyroid medications or corticosteroid drugs, having thyroid surgery, having a history of cancer, pregnant women, and those with end-stage renal disease, 4,356 subjects were included in the study. The odds ratio (OR) and 95% confidence interval (95%CI) for prediabetes in the general and euthyroid population per 1-SD increase in thyroid hormone resistance indices (PFTQI, TSHI, and lnTT4RI) were reported with logistic regression models.

RESULTS

One SD increase in PTFQI was significantly associated with lower odds of prediabetes even after total adjustment (OR:0.88; 95%CI: 0.82-0.94). The association was observed in women, non-smokers, and those with negative anti-thyroid peroxidase antibodies. In the euthyroid subgroup, one SD increase in PTFQI, TSHI, and lnTT4RI showed lower odds of prediabetes and [PTFQI: 0.89 (95%CI: 0.83-0.97); TSHI: 0.83 (95%CI: 0.74-0.94); lnTT4RI: 0.83 (95%CI: 0.74-0.93)]. We also found a negative correlation between thyroid hormone sensitivity indices and fasting plasma glucose (PTFQI: r =-0.094, TSHI:-0.1, and lnTT4RI: r =-0.098) and 2-h post-challenge glucose (PTFQI: r =-0.096, TSHI:-0.054, and lnTT4RI: r =-0.031).

CONCLUSION

Lower central sensitivity to thyroid hormone, as represented by increased TSHI, TT4RI, and PTFQI, is associated with a lower risk of prediabetes, even in euthyroid individuals.