Serum Copper and Zinc Status in Hypothyroidism: A Case–Control Study Evaluating Their Impact on Thyroid Function

Background: Hypothyroidism is a common endocrine disorder with significant metabolic consequences. Apart from iodine, trace elements such as zinc (Zn) and copper (Cu) play an essential role in thyroid hormone synthesis, metabolism, and action. Alterations in these micronutrients may contribute to the pathophysiology of hypothyroidism. Aim: To evaluate serum zinc and copper levels in patients with hypothyroidism and compare them with euthyroid healthy controls, and to assess their association with thyroid hormone levels. Materials and Methods: This hospital-based case–control study included 100 subjects aged 18–65 years. Fifty patients with biochemically confirmed hypothyroidism constituted the case group, while fifty age- and sexmatched euthyroid individuals served as controls. Serum T3, T4, and TSH were estimated by chemiluminescence immunoassay. Serum zinc and copper levels were measured using spectrophotometric methods. Statistical analysis was performed using Student’s t-test and correlation analysis. Results: Mean serum zinc levels were significantly lower in hypothyroid patients compared to controls (32.3 ± 19.1 vs 86.0 ± 17.9 µg/dL; p < 0.001). Serum copper levels showed no statistically significant difference between cases and controls (p > 0.05). Serum zinc demonstrated a significant negative correlation with TSH and a positive correlation with T3 and T4 levels. Conclusion: Hypothyroidism is associated with significantly reduced serum zinc levels, while serum copper levels remain largely unchanged. Zinc deficiency may play an important contributory role in thyroid dysfunction and may warrant attention during clinical evaluation of hypothyroid patients.