STATUS OF SERUM ZINC LEVELS IN FEMALES WITH THYROID DYSFUNCTION

Background: Low serum zinc levels have been connected to thyroid function in more than one way, but to date there is still arguments about the association between zinc deficiency and thyroid disease, particularly in females. The aim of this study was to assess status of serum zinc levels in a sample of females with thyroid dysfunction in comparison with those of normal thyroid function and to ascertain its association with thyroid hormone levels. Patients and Methods: A case control study was conducted on 225 females referred to the Endocrine Unit for definitive diagnosis of thyroid dysfunction and 100 females with normal thyroid function, serves as a control group. Results: The results revealed that the serum zinc levels were significantly lower in Hypothyroid females(62.2±16.3μg/dl) as compared to hyperthyroid (80.5±13.9μg/dl) and controls (86.2±13.2 μg/dl) with p=0.001.The prevalence of severe zinc deficiency (<50 μg/dl) was found to be significantly higher in hypothyroid females (25.0%) as compared to hyperthyroid females (3.0%), p-value of 0.01, whereas none of the controls had severe zinc deficiency. In the hypothyroid group, positive correlations of zinc were observed with FreeT3 and FreeT4 (p=0.007, p<0.001, respectively) and a negative correlation was observed with thyroid stimulating hormone (TSH), p<0.001.In the overall studied subjects, negative correlation was also found for zinc with TSH (p< 0.001).We did not observe a significant correlation ofFT3, FT4 and TSH with zinc in controls or in hyperthyroid group. Conclusions: Decreased serum zinc levels may lead to hypothyroidism in females. Efforts to increase zinc status in this group may help correct abnormal levels of thyroid hormones. Duhok Med J 2019; 13 (1):74-82.