Background: Hyperthyroidism can influence the metabolism and regulation of various essential nutrients, including vitamin D. Thyroid dysfunction is often associated with altered serum levels of vitamin D, potentially contributing to further metabolic complications. Aim: This study aims to investigate the relationship between thyroid hormone levels and vitamin D status in Iraqi patients diagnosed with hyperthyroidism. Methodology: A total of 50 patients with hyperthyroidism (23 males and 27 females), aged 20 to 72 years, attending the endocrinology clinic at Baghdad Medical City were included in this study. A control group consisting of 20 healthy individuals was also enrolled. Demographic data including age, gender, and body mass index (BMI) were recorded. Serum levels of thyroid hormones (T3, T4, and TSH) and vitamin D were measured and statistically analyzed. Results: Patients with hyperthyroidism showed significantly elevated levels of T3 and T4 (p<0.05) compared to the control group. In contrast, vitamin D levels were significantly lower in the hyperthyroid group (p<0.001). A significant negative correlation was observed between vitamin D levels and both T3 and T4. Conversely, vitamin D demonstrated a positive correlation with TSH levels. Conclusion: Hyperthyroidism is associated with reduced vitamin D levels, which may contribute to or worsen the clinical manifestations of vitamin D deficiency. Additionally, vitamin D deficiency may further aggravate thyroid dysfunction. The findings also highlight a higher prevalence of thyroid disorders among females compared to males.
Saadoun et al. (Wed,) studied this question.