Vol. 9, Issue 5, Part D (2025)

Background: Vitamin D plays a crucial role in immune regulation and hormonal functions, with its deficiency linked to the development of autoimmune diseases, including Hashimoto’s thyroiditis.

Aims of the study: Evaluate Vitamin D levels among patients with Hashimoto’s thyroiditis in Basrah City, Iraq, and assess its impact on disease progression and treatment response.

Methodology: This case-control study was conducted at Faiha Specialized Diabetes, Endocrine and Metabolism Center, Basrah, in 2024 to assess the relationship between vitamin D, TSH, and anti-TPO Ab in Hashimoto’s thyroiditis patients. Sixty-two patients and 62 controls were included. Patients with low vitamin D received supplementation or no treatment. Blood samples were analyzed using ECLIA before and after an 8-week intervention.

Result: Clinical characteristics of 62 Hashimoto’s patients and 62 controls showed no significant differences in age, BMI, gender, or smoking. Vitamin D levels were significantly lower in Hashimoto’s patients (15.1±0.3 ng/mL) vs. controls (36.4±0.6 ng/mL, p<0.001). After eight weeks, vitamin D supplementation significantly increased 25(OH)D levels (p<0.001) and reduced TSH (23.4±2.9 to 6.3±0.98 μIU/mL, p<0.001) and anti-TPO Ab (302.9±34.1 to 198.6±28.3 IU/mL, p=0.005). Non-supplemented patients showed minimal anti-TPO Ab reduction (p=0.246).

Conclusions: Vitamin D supplementation significantly improved serum 25(OH)D levels, reduced TSH, and lowered anti-TPO Ab in Hashimoto’s patients. This suggests that vitamin D modulates immune responses, reducing thyroid autoimmunity by suppressing inflammatory cytokines and regulating T-regulatory cell function, potentially improving disease outcomes.