Abstract
Background: Autoimmune diseases are a group of disorders with heterogeneity in epidemiology and in clinical phenotype, characterized by tissue and organ damage as a result of auto attack against self antigens. Vitamin D receptors have not only been identified in tissues that take part in calcium homeostasis, but also in a variety of cell groups that mainly interfere in immune regulation. Epidemiological
evidence has shown that low levels of vitamin D are related with various autoimmune diseases. The aim of our study was to compare vitamin D levels in patients with autoimmune diseases and in healthy controls. Materials and Methods: The sample group consisted of 100 patients with a confirmed diagnosis of an autoimmune disease and 40 healthy volunteers. Use of medications or treatments that decrease vitamin D levels or interfere with mass bone loss was a strict exclusion criterion. Results: Study results demonstrated statistically significant differences in vitamin D levels between patients and healthy controls, regardless of possible confounders such as gender, as well as complement C3, complement C4 and serum calcium levels. Since these factors presented statistically significant differences between patients and healthy controls, they were selected as potential
confounders. Other clinical or demographic characteristics which significantly affect vitamin D levels in patients were not observed. Conclusions: Overall, this study highlights the significant role of Vitamin D in autoimmune disease development for the first time in the Greek population. A statistically significant difference in vitamin D levels between patients and healthy controls was observed.
Key words: vitamin D, autoimmunity, autoimmune diseases, confounders