Is Vitamin D Deficiency Associated with Chronic Lymphocytic Thyroiditis?

Vitamin D deficiency is a very common global health problem. Evidence from recent studies focuses on the extraskeletal effects of vitamin D (Vit D) deficiency. Chronic lymphocytic thyroiditis (or Hashimoto's thyroiditis) is an autoimmune disease of the thyroid. Although there are many studies reporting that autoimmune thyroid diseases may be associated with Vitamin D deficiency, this is still a controversial issue that has not yet been proven. In this study, we aimed to appraise whether there is a relationship between lymphocytic thyroiditis diagnosed by histopathological evaluation and Vitamin D deficiency.

Data of 256 patients whom were operated by a single surgeon in a single center between 2012 and 2017 and whose preoperative vitamin D tests and thyroid pathologies have been collected, were retrospectively evaluated. Due to the pathological examination, two groups were formed considering the presence of lymphocytic thyroiditis (Group 1), and the absence of lymphocytic thyroiditis (Group 2). Vitamin D deficiency was defined as the level <20 ng/mL (50 nmol/L) and Vitamin D insufficiency was defined as the level 21-29 ng/mL (525-725 nmol/L).

There were 108 (92F/16M) patients in Group 1, and 148 (116F/32M) patients in Group 2, and the mean age was lower in Group 1 (p=0.053). The mean vitamin D levels (16.6±15.2 vs. 14±10, p=0.409) and vitamin D deficiency rates (67.6% vs. 72.3%, p=0.416) were found similar between the Groups 1 and 2. No positive significant correlation was found between lymphocytic thyroiditis and vitamin D level or vitamin D deficiency rates. There was a positive correlation between lymphocytic thyroiditis and age, preoperative thyroid-stimulating hormone level, preoperative anti-thyroglobulin ,and anti-thyroid peroxidase levels, but no significant relationship was found with Vitamin D level.

According to our results, lymphocytic thyroiditis was not associated with either Vitamin D deficiency or Vitamin D level.