Correlation between Vitamin D levels and thyroid autoantibodies in newly diagnosed hashimoto's thyroiditis patients

Vitamin D plays a role in numerous metabolic functions. In this study we aimed to assess vitamin D levels in Hashimoto's Thyroditis (HT) patients, and demonstrate the relationship between these levels and thyroid function tests or thyroid autoantibodies.

A retrospective analysis of 112 newly diagnosed euthyroid HT (EHT) patients and 178 healthy controls was carried out. 25-OH D level was classified as vitamin D deficiency, vitamin D insufficiency, and vitamin D sufficient.

Mean age was 35.33±11.54 years in the patient group, and 35.84±10.9 in the control group (p=0.777). Compared with the healthy controls, patients in the EHT group had significantly lower vitamin D levels (p=0.007), and a significantly higher prevalence of vitamin D deficiency (p=0.001). While there was a negative correlation between vitamin D levels and anti-TPO values (r=-0.133, p=0.023), there was no significant relationship between vitamin D and TSH, fT4, fT3, and anti-TG values (p>0.05).

This study showed that EHT patients had lower vitamin D levels compared to healthy controls, and there was a significant negative correlation between vitamin D levels and anti-TPO levels. Based on our study, patients diagnosed with HT should undergo vitamin D screening, and replacement if necessary.