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≤ …