Effects of iodine and thyroid hormones in inducing and treating Hashimoto's thyroiditis

Aim: The effect of an iodine prophylaxis on the induction of Hashimoto's th yroiditis as well as the influence of various therapeutic approaches on the course of antithyroglobulin (TgAb) and antiperoxidase (TPOAb) antibodies i n manifest diseases are evaluated. Method: A collective of 375 euthyroid su bjects without relevant goiter received daily doses of 200 micrograms iodid e, weekly doses of 1.53 milligrams iodide, or no medication. A second group of 377 patients suffering from Hashimoto's thyroiditis was treated with a non-suppressive hormone medication, a suppressive hormone administration, a combination of a non-suppressive hormone therapy with low dose iodide (50- 150 micrograms/day), mere iodide in doses of 200 micrograms/day, or receive d no therapy. The mean observation period in these two groups was 860 and 8 48 days, respectively. Results: There was no significant increase of the an tibody levels in the subgroup with 200 micrograms iodide/day and in the non -treated subjects of the first collective. However, the group that received 1.53 milligrams iodide/week presented a distinct increase of the TgAb as w ell as the TPOAb, and the incidence of Hashimoto's thyroiditis was 4-fold h igher than in the two other subgroups. The patients of the second collectiv e revealed a significant decrease of the TgAb in the subgroups treated with up to 200 micrograms iodide/day, while the reduction of the TPOAb depended on the thyrotropin level and was most significant in the suppressed group (p < 0.0001). Conclusion: To lower the incidence of autoimmune thyroid dise ases in predisposed subjects, a daily iodine supplementation seems to be su perior to high-dose weekly administrations, A hormone therapy combined with a daily, low-dose iodine medication is able to reduce the TgAb and the TPO Ab levels even in patients with Hashimoto's thyroiditis.