Effects of selenium in patients with autoimmune thyroiditis

Background: In the last decades, a number of clinical studies have been conducted where both the positive and neutral effects of Se on thyroid autoimmunity have been demonstrated. Aims: The aim of our study was to assess the effects of selenmethionine among euthyroid patients with elevated TPO-Ab (TPO > 100 IU/ml) and patients with subclinical hypothyroidism and elevated TPO-Ab. Materials and methods: 40 euthyroid patients with elevated TPO-Ab and 11 patients with subclinical hypothyroidism plus elevated TPO-Ab were included in our study. Patients of both categories were randomized to recieve Se 200 μg/day or to the dynamic observation. TSH, f. T4, f. T3, AT-TPO were measured at baseline and every 3 months of follow-up. The volume and echogenicity of the thyroid were also evaluated every 3 month of follow-up period (12 month). Results: There were no significant difference between the groups on the dynamics of TSH, f. T3, f. T4, AT-TPO titers, volume and the echogenicity of the thyroid gland during the whole observational period among euthyroid patients with elevated TPO-Ab. Among the patients with subclinical hypothyroidism there were also no significant difference between the groups on the dynamics of f. T3, f. T4, AT-TPO titers, volume and the echogenicity of the thyroid gland during the whole observational period. But by the 12 month of the follow-up there were significantly more euthyroid patients in Se group compare to dynamic observation group. Conclusions: Our study, failed to show possitive effects of Se supplementation on thyroid autoimmunity.