Effects of Vitamin D deficiency treatment on metabolic markers in Hashimoto thyroiditis patients

Background: The aim of the current trial was to investigate the effect of Vitamin D treatment on metabolic markers in people with Vitamin D deficiency and thyroid autoimmunity. Materials and Methods: In this double‑blind, randomized, placebo‑controlled clinical trial, 65 Vitamin D deficient euthyroid or hypothyroid patients with positive TPO‑Ab were enrolled. They randomly allocated into two groups to receive oral Vitamin D3 (50000 IU weekly) and placebo for 12 weeks. Serum concentration of calcium, phosphorus, albumin, C‑reactive protein, blood urea nitrogen, creatinine, glycated hemoglobin (HbA1c), insulin, fasting plasma glucose (FPG), triglyceride (TG), total cholesterol, and high‑density lipoprotein were measured in both groups before and after the trial. Homeostasis model assessment estimates of beta cell function (HOMA‑B) and HOMA‑insulin resistance (HOMA‑IR) were calculated before and after trial in both groups. Results: Thirty‑three and thirty‑two participants were allocated to Vitamin D‑treated and placebo‑treated groups, respectively. Mean (standard error) level of Vitamin D increased significantly in Vitamin D‑treated group (45.53 [1.84] ng/mL vs. 12.76 [0.74] ng/mL, P = 0.001). The mean of HbA1c and insulin was increased significantly both in Vitamin D‑treated and placebo‑treated groups (P < 0.05). Other variables did not meet a significant change after trial (P = NS). In between‑group comparison, there was not any significant difference between Vitamin D‑treated and placebo‑treated groups regarding measures of HOMA‑B, HOMA‑IR, FPG, HbA1c, and TG (P = NS). Conclusion: Our findings showed that weekly 50000 IU oral Vitamin D3 for 12 weeks did not improve metabolic markers, IR, or insulin secretion in Vitamin D deficient patients with Hashimoto thyroiditis.