Endocrine Abstracts

Introduction: Although, vitamin D (vit D) mainly regulates calcium and phosphate metabolisms, its deficiency may also contribute to the development of some carcinomas, autoimmune, and cardiac diseases. Vit D deficiency has been defined to correlate with increased autoimmune disease such as type 1 diabetes mellitus, rheumatoid arthritis, autoimmune thyroid diseases (AITD). Previous studies suggested that patients with AITD had lower vit D levels when compared with healthy controls. Moreover, vit D supplements were found to prevent the development and progression of autoimmune disorders such as type 1 diabetes mellitus and multiple sclerosis. Thus, we aimed to assess the effect of vit D on thyroid antibody titers in patients with AITD.

Materials and methods: Twenty-four participants were enrolled into the study. All of the participants were diagnosed with AITD and vit D deficiency. We assayed the serum anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) antibody levels before and a month after the vit D replacement. The daily dose of the vit D replacement was 2000 International Units (I.U).

Results: The AITD induced disorders in participants were as following: subclinical hypothyroidism: 66.6%, subclinical hyperthyroidism: 8.3%, overt hypothyroidism: 12.5%, and overt hyperthyroidism: 12.5%. Mean vit D level was 13.1±1.2 ng/ml. Before and after vit D replacement, anti-TPO titers were 276.6±42.7 IU/ml, 257.1±40.1 IU/ml (P<0.001); and anti-Tg titers were 371.9±64.3 IU/ml, 269.3±36.4 IU/ml (P<0.001) respectively. There was a statistically significant decrease in the anti-TPO and anti-Tg levels after the vit D replacement.

Conclusions: Vit D supplements seem to reduce thyroid antibody titers which play the main roles in the development and progression of AITDs. Therefore, vit D therapy may be used in the treatment of patients with AITD, particularly those with vit D deficiency. Further studies are needed to assess the role of vitD replacement therapy in the treatment of autoimmune diseases.