Relationship between 25-hydroxyvitamin D and thyroid function and thyroid autoantibodies in patients with type 2 diabetes mellitus

ObjectiveTo investigate the relationship between serum 25-hydroxyvitamin D (25-OH-VD) level and thyroid function and thyroid autoantibodies in patients with type 2 diabetes mellitus.

MethodsA total of 181 patients with type 2 diabetes mellitus were selected, including 101 patients with vitamin D deficiency, 62 patients with vitamin D insufficiency, and 18 patients with vitamin D sufficiency.The correlations between 25-OH-VD and total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), thyroid stimulating hormone (TSH), anti-thyroglobulin antibody (TgAb), thyroid peroxidase antibody (TPOAb), fasting blood glucose, glycosylated hemoglobin (HbA1c) and blood lipids among the three groups were analyzed.

ResultsThere was no significant difference in thyroid function between the vitamin D deficient group and the vitamin D sufficient group (P>0.05), but the levels of TgAb, TPOAb, Cholesterol (TC), triglyceride (TG) and HbA1c in the vitamin D deficient group were higher than those in the vitamin D sufficient group (P < 0.05).Correlation analysis showed that 25-OH-VD was negatively correlated with HbA1c, TT3, TgAb, TPOAb, TG, TC and sex (P < 0.05).Logistic regression results found that sex and 25-OH-VD were the influencing factor of TPOAb positivity.

ConclusionsVitamin D deficiency is common in type 2 diabetes mellitus.The level of vitamin D deficiency is correlated with the level of HbA1c, moreover, high 25-OH-VD level is a protective factor for TPOAb positivity.