(Association between Vitamin D Deficiency and Thyroid Autoantibodies in Midlife Women with Hypothyroidism in Erbil, Iraq)

Abstract

Vitamin D deficiency represents a major global health issue, affecting over one billion individuals. Patients with hypothyroidism often have low vitamin D levels, which are associated with autoimmune diseases. This study aimed to investigate vitamin D status in relation to thyroid autoantibodies. A case-control study design was conducted on 90 women their age around (40-65) years, including 45 patients diagnosed with hypothyroidism and 45 age-matched healthy controls, who attended several hospitals in Erbil city. The demographic data, which were gathered through a designed questionnaire, and biochemical data, including (TSH, FT3, FT4, vitamin D, Anti-Tg and Anti-TPO) were analyzed by the statistical analysis SPSS and GraphPad, including Independent-Samples T-test, Pearson correlation, and Multi linear regression. The results showed a statistically significant drop in the levels of serum vitamin D in hypothyroidism compared with healthy women (P < 0.05), while Anti-Tg and Anti-TPO autoantibodies were highly significantly elevated in the hypothyroid group (p < 0.001). Pearson correlation analysis revealed significant negative correlation between Anti-TPO, Anti-Tg, and Vitamin D levels(p < 0.001), and multiple regression analysis indicated both Anti-TPO and Anti-Tg to be highly, significantly negatively correlated with vitamin D in serum (p < 0.01), with no significant relationship between TSH or BMI and vitamin D. A significant association between hypothyroidism and hypovitaminosis D in this study, indicating that vitamin D deficiency may contribute to thyroid dysfunction. Accordingly, vitamin D depletion in hypothyroid patients is independently driven by thyroid autoimmunity rather than TSH or BMI.