Selenium Concentration in Korean Patients with Thyroid Disease: a Preliminary Report

Abstract

Background and Objectives: Selenium is an important trace element for thyroid hormone metabolism, and its deficiency can cause hypothyroidism. Serum selenium concentration is the best biomarker to reflect selenium intake and reserve, although other markers can reflect. Therefore, we preliminarily assessed serum and urine selenium concentrations in patients with thyroid disease compared to those of a healthy population. We also investigated the correlation between serum and urine selenium concentration, thyroid hormone and urinary iodine concentration (UIC). Materials and Methods: A total of 97 patients (32 men, 65 women, 52.4±14.7 years) with benign thyroid nodules or thyroid dysfunction who visited the Samsung Medical Center between 2008 and 2013 were included. Data for 175 healthy subjects provided by Lee et al. were used as the control. Serum T3, free T4, and thyroid stimulating hormone (TSH) were measured using commercialized RIA or IRMA kits. Serum/urine selenium and UIC were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Results: Median serum selenium concentration was 110 μg/L (95% CI, 73-156). Median urine selenium concentration was 66.3 μg/gCr (95% CI, 28.7-283.5). Compared to 175 healthy subjects (serum 84 μg/L [95% CI, 30-144], urine 34.5 μg/gCr [95% CI, 0.8-107.2]), serum and urine selenium concentrations of patients with thyroid disease were significantly higher than those of healthy subjects (p＜0.001). Serum selenium concentration was significantly correlated with urine selenium concentration after log transformation (r=0.88, p=0.022), but was not significantly correlated with UIC, T3, free T4 and TSH. Conclusion: Selenium concentrations of patients with thyroid disease were significantly higher than those of healthy subjects. Serum selenium concentration was significantly correlated with urine selenium concentration.