Evaluation of the Effects of Vitamin D Levels on the Course Of Graves’ Disease

Objective: In recent years, low vitamin D levels in patients with autoimmune diseases have drawn attention. This study aimed to explore the association between serum 25-hydroxyvitamin D (25(OH) D) concentrations and both clinical and laboratory markers indicative of disease progression in patients with Graves’ disease (GD). Methods: This retrospective analysis included patients diagnosed with GD between 2017 and 2022. Patients were categorized based on their serum 25(OH)D levels and whether they received cholecal ciferol supplementation in addition to standard antithyroid therapy (ATT). Among 148 newly diag nosed, thyrotropin receptor antibody (TRAb)–positive GD patients, 45 individuals were classified as vitamin D deficient (<10 ng/mL), 53 as insufficient (10-20 ng/mL), and 50 as sufficient (≥20 ng/mL). Results: Baseline analysis demonstrated a significant inverse relationship between 25(OH)D levels and free triiodothyronine (fT3), the fT3/free thyroxine (fT4) ratio, TRAb, antithyroid peroxidase (anti thyroid peroxidase) antibodies, and duration to remission (P = .017, P = .002, P < .001, P = .027, and P = .014, respectively). However, no statistically significant differences were noted in total ATT dosage, time to achieve euthyroidism, remission duration, or relapse rates between patients who received cholecalciferol in addition to ATT (n = 62) and those who did not (n = 50). Conclusion: The study revealed that TRAb and fT3/fT4 levels, which are predictors of GD severity and prognosis, were higher in patients with vitamin D deficiency, and the time to achieve remission was longer. It may be suggested that vitamin D deficiency may be associated with a worse outcome in the GD process. Cite this article as: Akyol F, Çakır İ. Evaluation of the effects of vitamin D levels on the course of graves’ disease. Endocrinol Res Pract. 2025;29(4):327-332.