Effect of Vitamin D deficiency treatment on thyroid function and autoimmunity markers in Hashimoto’s thyroiditis: A double-blind randomized placebo-controlled clinical trial

Background: the link between autoimmune thyroid diseases and vitamin d deficiency has been reported. however,there are controversies in this regard. we conducted a double-blind randomized placebo-controlled clinical trial to investigate the effect of vitamin d deficiency treatment on thyroid function and autoimmunity marker (thyroid peroxidase antibody [tpo-ab]) in patients with hashimoto’s thyroiditis. materials and methods: fifty-six patients with hashimoto’s thyroiditis and vitamin d deficiency (25-hydroxyvitamin d level ≤20 ng/ml) were randomly allocated into two groups to receive vitamin d (50000 iu/week,orally) or placebo for 12 weeks,as vitamin d-treated (n = 30) and control (n = 26) groups,respectively. tpo-ab,thyroid-stimulating hormone (tsh),parathormone,calcium,albumin,and creatinine concentrations were compared before and after trial between and within groups. the data were presented as mean (standard error [se]) and analyzed by appropriate tests. results: mean (se) of vitamin d was increased in vitamin d-treated group (45.5 [1.8] ng/ml vs. 12.7 [0.7] ng/ml,p = 0.01). mean (se) of tpo-ab did not significantly change in both groups (734 [102.93] iu/ml vs. 820.25 [98.92] iu/ml,p = 0.14 in vitamin d-treated and 750.03 [108.7] [iu/ml] vs. 838.07 [99.4] [iu/ml] in placebo-treated group,p = 0.15). mean (se) of tsh was not changed in both groups after trial,p = 0.4 and p = 0.15 for vitamin d-treated and control groups,respectively. no significant difference was observed between two study groups in none studied variables (p > 0.05). conclusion: vitamin d treatment in vitamin d deficient patients with hashimoto’s thyroiditis could not have significant effect on thyroid function and autoimmunity. © 2017 journal of research in medical sciences.