Atorvastatin potentiates the effect of selenomethionine on thyroid autoimmunity in euthyroid women with Hashimoto's thyroiditis.

Objective: In many studies, selenium supplementation decreased serum titers of thyroid antibodies. The aim of the study was to investigate whether statin therapy determines selenium action on thyroid autoimmunity.
Methods: This prospective case-control study enrolled 42 euthyroid women with Hashimoto's thyroiditis and normal vitamin D status, 20 of whom had been treated with atorvastatin (40 mg daily) for at least 6 months. All patients received selenomethionine (200 µg daily) for 6 months. Plasma levels of lipids, serum titers of thyroid peroxidase (TPOAb) and thyroglobulin (TgAb) antibodies, as well as serum levels of thyrotropin, free thyroid hormones, and 25-hydroxyvitamin D were determined at the beginning and at the end of the study.
Results: At baseline, there were no differences between both treatment arms in plasma lipids, titers of thyroid antibodies, serum levels of thyrotropin, free thyroid hormones, and 25-hydroxyvitamin D. Selenometionine decreased titers of TPOAb (from 843 ± 228 to 562 ± 189 U/mL) and TgAb (from 795 ± 286 to 501 ± 216 U/mL) in atorvastatin-treated women, as well as titers of TPOAb (from 892 ± 247 to 705 ± 205 U/mL) and TgAb (from 810 ± 301 to 645 ± 224 U/mL) in statin-naive women. The changes in antibody titers were more pronounced in women receiving atorvastatin (between-group difference: 94 [32-156] [TPOAb]; 129 [52-206] [TgAb]). Treatment-induced changes in TPOAb and TgAb correlated positively with baseline thyroid antibody titers. Circulating levels of lipids, free thyroxine, free triiodothyronine, and 25-hydroxyvitamin D remained at similar levels throughout the study.
Conclusions: The obtained results indicate that the decrease in titers of thyroid antibodies was potentiated by atorvastatin use.