Evaluation of Serum Zinc, Copper Level and their Correlation with Cu/Zn Ratio and FT3/FT4 Ratio in Hypothyroidism BC08-BC10
Dr. GS Santhini,
No. 20, Veerabadra Nagar, Medavakkam, Chennai, Tamil Nadu, India.
Introduction: Hypothyroidism is a condition characterised by deficiency of thyroid hormones due to defect in hormone synthesis pathway or development of resistance at the tissue level. It has been observed that trace elements may influence hormonal function at several levels. Various studies suggest that reduction in zinc and copper levels adversely affect the endocrine system.
Aim: To determine the serum zinc and copper levels in hypothyroidism and its effect on the progression of hypothyroidism.
Materials and Methods: The present case-control study was conducted among 80 hypothyroid patients and 80 apparently healthy individuals aged 18-55 years. Serum zinc (Zn) and copper (Cu) were measured by the colorimetric assay using semi-automated analyser. Free triiodothyronine (T3), free thyroxine (T4) and Thyroid stimulating hormone (TSH) were measured using the chemiluminiscence immunoassay method. Individual parameters by independent sample t-test and correlation was analysed by Pearson’s correlation test. The p-value <0.05 was considered significant.
Results: No statistical difference was observed in the BMI among the two groups. Zinc levels in hypothyroid group (85.21 µg/dL) were significantly (p-value=0.002) lower as compared to the control group (100.83 µg/dL). However, copper levels in hypothyroid group (151.1 µg/dL) were increased as compared to the control group (140.5 µg/dL) but the difference was not statistically significant (p=0.09). In the hypothyroid patients, the Copper to Zinc (Cu/Zn) ratio was 1.7/1, which was higher than that of control group 1.3/1 (p-value=0.001). Zinc was found to be negatively correlated with TSH (r-value=-0.248; p-value=0.033) and positively correlated with FT4 (r-value=0.374; p-value=0.001). Cu/Zn ratio was found to have a weak positive correlation with FT3/FT4 ratio (r=0.0875; p-value=0.45).
Conclusion: This study proved the presence of imbalance of trace elements like zinc and copper among hypothyroid patients and thereby emphasises on their importance in maintenance of thyroid homeostasis.