EXPRESS: Effects of Selenium Supplementation on Cognitive Function in Patients with Hyperthyroidism Caused by Graves'...

The study investigated the effects of selenium supplementation on cognitive function in patients with Graves' hyperthyroidism.

A total of 124 newly diagnosed patients with Graves' hyperthyroidism and with a baseline Montreal Cognitive Assessment (MoCA) score < 26 were recruited. Participants were randomly assigned to either the conventional treatment group (n = 62) or the combined treatment group (n = 62). Cognitive and biochemical assessments were conducted at baseline and at 4, 8, and 12 weeks post-intervention. The primary outcomes were MoCA score and blood selenium concentration. Secondary outcomes included total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH) and thyroid receptor antibodies (TRAb).

At the 4th, 8th and 12th weeks of follow-up, the MoCA scores, blood selenium concentrations and TSH levels in the combined treatment group were significantly higher than those in the conventional treatment group (all p < 0.05), whereas TRAb levels were significantly lower (p < 0.05). Linear mixed-effects modeling revealed statistically significant group × time interactions for MoCA scores (β = 1.914, 95% CI: 1.152-2.018, p = 0.012), blood selenium concentrations (β = 21.132, 95% CI: 18.302-30.171, p < 0.001), TRAb levels (β = -3.286, 95% CI: -5.575- -1.120, p < 0.001) and TSH levels (β = 1.136, 95% CI: 0.812-1.398, p < 0.001). Linear correlation analysis demonstrated that changes in blood selenium concentrations from baseline to at week 12 were moderately positively correlated with changes in MoCA scores (r = 0.538, p < 0.001), moderately negatively correlated with changes in FT4 levels (r = -0.437, p < 0.001), and strongly negatively correlated with changes in TRAb levels (r = - 0.722, p < 0.001). Partial correlation analysis confirmed that changes in blood selenium concentrations remained significantly negatively associated with changes in TRAb levels (r = - 0.690, p < 0.001). Furthermore, binary logistic regression analysis indicated that improvement in cognitive function among patients with Graves' hyperthyroidism was significantly associated with treatment modality (OR = 0.046, 95% CI: 0.017-0.123, p < 0.001).

Selenium supplementation therapy confers significant cognitive benefits in patients with Graves' hyperthyroidism.