Effects of Vitamin D treatment on thyroid autoimmunity

Background: vitamin d was shown to be related to autoimmune thyroid diseases (aitds) in the previous studies. we aimed to investigate the relationship between vitamin d and thyroid autoimmunity. materials and methods: eighty‑two patients,diagnosed with aitd by the endocrinology outpatient clinic,were included in this prospective study. all of the patients had both aitd and vitamin d deficiency,defined as serum values <20 ng/ml. they were randomly assigned into two groups. the first group included 46 patients and the second one included 36 patients. the first group was treated with vitamin d for 1 month at 1000 iu/day. the second group served as the control group and was not treated with vitamin d replacement. serum thyroid‑stimulating hormone,free t4 (ft4),thyroid peroxidase antibody (tpo‑ab),thyroglobulin antibody (tgab),and vitamin d levels were measured at the initiation of the study and again at 1 month in all patients. results: two groups were similar with regard to age,sex,and type of thyroid disease. whereas tpo‑ab (before; 278.3 � 218.4 iu/ml and after; 267.9 � 200.7 iu/ml) and tgab (before; 331.9 � 268.1 iu/ml and after; 275.4 � 187.3 iu/ml) levels were significantly decreased by the vitamin d replacement therapy in group 1 (p = 0.02,p = 0.03,respectively),the evaluated parameters in the control group did not significantly change (p = 0.869,p = 0.530,respectively). in addition,thyroid function tests did not significantly change with vitamin d replacement in two groups. conclusion: vitamin d deficiency may contribute to the pathogenesis of aitds. since supplementation of the vitamin d decreased thyroid antibody titers in this study in vitamin d deficient subjects,in the future vitamin d may become a part of aitds’ treatment,especially in those with vitamin d insufficiency. further clinical and experimental studies are required to understand the effect of vitamin d on aitd. � 2016 journal of research in medical sciences.