Copper/zinc ratio and erythrocyte superoxide dismutase in patients with thyroid nodules.

The aim of this study was to evaluate biomarkers of zinc and copper status in patients with thyroid nodules. A cross-sectional study of 122 participants with thyroid nodules, diagnosed with cytological examinations (Nodule group) and 72 healthy subjects (Control group) were performed. Anthropometric data were collected; plasma concentrations of zinc and copper were analyzed by flame atomic absorption spectrophotometry and erythrocyte superoxide dismutase (SOD) activity was determined in an automatic biochemical analyzer using spectrophotometry to quantify the enzyme activity. The content of Zn in plasma was lower in the Nodule group than in the Control group, but plasma copper, copper/zinc ratio and erythrocyte SOD activity were higher in the Nodule group (p < 0.001). The levels of Cu and Zn are in the normal range, but the ratio Cu/Zn is altered in nodules group. Thyroid nodule patients exhibited changes in zinc and copper biomarker status compared to healthy individuals. The Cu/Zn ratio is a much more sensitive parameter for evaluating mineral metabolism in thyroid diseases.