The Relationship Between Thyroid Antibodies and Vitamin D Level in Primary Hypothyroidism

Vitamin D deficiency is a global health problem. Its deficiency has been reported to be associated with different autoimmune diseases.

The aim of this study was to evaluate the relationship between vitamin D level and thyroid antibodies in autoimmune hypothyroidism.

A total number of 150 individuals were enrolled in this study. They were divided into the fallowing groups: group I included 50 patients with autoimmune thyroid disease (AITD), group II included 50 patients without autoimmune thyroid disease. Group III included 50 apparently healthy participants representing a control group. All participants underwent a detailed clinical examination and laboratory tests including, 25 (OH) vitamin D, thyroid-stimulating hormone (TSH) and thyroid autoantibodies assessment, including anti-thyroid peroxidase antibodies (anti-TPO) and anti-thyroglobulin antibodies (anti-TG).

Serum levels of 25 (OH) vitamin D recorded a highly significant difference between the studies groups (20,76±6,31 ng/ml in group I vs. 24,37±9,05ng/ml in group II vs. 24,57±6,45ng/ml in group III, p<0,01). Moreover, there was a highly significant difference between patients with AITD and patients without AITD (20,76±6,31ng/ml vs. 24,37±9,05ng/ml, respectively; p<0,01). The concentration of anti-TPO and anti-TG antibodies were statistically significant higher in patients with vitamin D deficiency (p< 0,001). Serum TSH were significantly higher in group I (p< 0,001).

Significantly low levels of vitamin D were documented in patients with AITD that were related to the presence of anti-thyroid antibodies and higher level thyroid-stimulation hormone (TSH), suggesting the involvement of vitamin D in the pathogenesis of AITD and the advisability of supplementation.