Endocrine Abstracts

Introduction: Vitamin D, primarily known for its role in calcium–phosphorus homeostasis, is also a significant immunomodulatory factor. Vitamin D deficiency has been reported in some autoimmune disorders. Recently, vitamin D level in autoimmune thyroiditis (Hashimoto’s thyroiditis (HT)) has become the subject of researchers’ interest.

Objectives: This study aims to assess vitamin 25-OH-D3 levels in HT patients in comparison to a control group in the Polish population. This would be the first attempt conducted in this poor sunlight exposure region.

Patients and methods: The group consisted of 62 subjects diagnosed with HT (mean age 49.15±15.51 and female:male ratio 56:6) and 32 healthy controls matched with age and sex (mean age 46.09±14.32 and female:male ratio 28:4). All blood samples were collected in the first quarter of the year to minimize the impact of seasonal fluctuations of vitamin D concentrations.

Results: In the HT group the mean vitamin D level was 20.09 nmol/l (S.D.±12.66), compared to 30.31 nmol/l (S.D.±19.49) in the controls, P=0.014. All the patients and controls were insufficient (according to the normal level – a serum concentration between 75 and 125 nmol/l). The deficiency (vitamin D <50 nmol/l) was significantly more common among HT patients compared to the controls (61–98.4 vs 27–84.4%), P=0.029.

Conclusions: Statistically significant difference in serum vitamin D concentrations between patients with HT and the control group has been found in our study, which is in accordance with the literature. This may suggest vitamin D deficiency is one of the environmental factors in HT development, although further studies are needed to confirm these observations.

Keywords: Autoimmune thyroiditis, vitamin D, etiopathogenesis, autoimmunity.