Serum vitamin D levels are decreased in patients without remission of Graves’ disease

Graves’ disease (GD) is an autoimmune thyroid disease in which thyrotropin receptor autoantibodies (TRAb) cause hyperthyroidism. Although medical treatment with antithyroid drugs (ATD) is the first choice treatment for GD in Japan and Europe, a remission rate of GD with ATD is not satisfactory, and many patients need long-term treatment with ATD or further treatments such as radioactive iodine therapy or thyroidectomy [1]. Therefore, it is very important to identify the factors relating to the remission of GD. It has been recently shown that vitamin D deficiency is associated with the onset and/or development of several autoimmune diseases, including multiple sclerosis (MS), inflammatory bowel disease (IBD), and type 1 diabetes (T1DM) [2]. Furthermore, it has been reported more recently that patients with autoimmune thyroid diseases including GD have lower vitamin D status [3, 4]. However, there is no study comparing vitamin D status between the patients with and without remission of GD. In the present study, we examined vitamin D status in female patients with and without remission of GD and discussed the role of vitamin D in the pathogenesis and/or prognosis of GD.