Relationship between low vitamin D levels with Hashimoto thyroiditis

Introduction/Objective. Vitamin D not only plays a role in calcium and phosphorus metabolism, but also has antiproliferative, prodifferentiation, anti-inflammatory and immunomodulatory effects. The aim of this study was to investigate the association between vitamin D deficiency in individuals with autoimmune Hashimoto’s thyroiditis. Methods. A total of 156 patients were enrolled and divided into two groups. First group included 108 patients with 25 (OH) D insufficiency, and second included 48 individuals with normal 25 (OH) D levels. All participants underwent a detailed clinical examination, laboratory tests for thyroid function [T3, fT4, TSH, thyroid antibodies (TPO-Ab, and TG-Ab)], as well as ultrasound scanning (thyroid volume and Doppler characteristics). Results. The patients with vitamin D insufficiency (n = 108 (69.2%)) were predominantly female and had a higher body mass index than the patients with normal vitamin D levels. The group with vitamin D insufficiency had statistically significantly higher TSH levels. The prevalence of positive thyroid antibodies was higher in the vitamin D insufficiency group, while thyroid volume, superior thyroid artery, and inferior thyroid arteries resistance index, as well as the prevalence of positive circular dichroism signals, were significantly higher in the vitamin D insufficiency group. Out of the 156 subjects, 44 were diagnosed with thyroiditis (28.2%). The mean serum level of 25 (OH) D was statistically notably lower in patients with thyroiditis (20.23 ± 8.10 ng/mL) than in the group without thyroiditis (25.44 ± 8.38 ng/mL), p < 0.001. Conclusion. There was an association between vitamin D insufficiency and hypothyroidism in subjects with Hashimoto’s thyroiditis.