EFFECTS OF ORAL SELENIUM REPLACEMENT ON TSH IN PATIENTS WITH SUBCLINIC HIPOTIROIDISM WITH LOW SERUM SELENIUM LEVELS

Abstract

OBJECTIVE: Selenium is an essential component of important metabolic pathways of the human body. Proteins in which selenium is added to the active site in the form of selenocysteine are defined as selenoproteins and they require selenium to fulfill their functions. Glutathioneperoxidase (GPXs) is found in such selenoproteins as Thioredoxinreductase (TRs) and Iodothyroninedeiodinase (ID). Selenoproteins contribute to thyroid hormone biosynthesis and metabolism and the control of the antioxidant defence system. In our study, we aimed to reveal how often patients with subclinical hypothyroidism and autoimmune thyroiditis are accompanied by low serum selenium level and the effects of oral selenium replacement on Tiroit Stimulating Hormone (TSH) in patients with low selenium.MATERIAL AND METHODS: In our study, we evaluated 69 patients who were with asymptomatic subclinical hypothyroidism and aged older than 18 and who applied admitted to our outpatient/out-patient clinic between December 2019 and July 2020. Patients with serum selenium levels lower than 80 μg / L were given 83 mcg of selenomethionine in a soft gel capsule for 3 months. No other treatment was applied. At the end of the third month, serum thyroid hormone profile and selenium levels were measured in all patients. Changes in TSH levels were observed in patients with autoimmune thyroiditis with subclinical hypothyroidism after oral selenium replacement by using percentiles.RESULTS: In our study, 69 patients with asymptomatic subclinical hypothyroidism diagnosed in our outpatient clinic between December 2019 and July 2020 were evaluated. Serum selenium level was identified as normal in 12 (28%) of 43 patients, and serum selenium level was identified as low (<80 μg / L) in 31 (72%) patients. TSH values were found as regressed within normal limits (0,5mIU/L 10.00 mIU / L) in 3 (10%) patients, the TSH value was identified as still in the range of 4.26 mIU / L-10.00 mIU / L in 9 (29%) patients and levothyroxine treatment was started in these patients.CONCLUSIONS: In our study, we evaluated the short-term effects of oral selenium replacement in asymptomatic autoimmune subclinical hypothyroid patients with selenium deficiency, on serum TSH values and we observed that 61% of patients were euthyroid within 3 months. Replacing selenium deficiency has positive effects on the inflammatory and oxidative damage processes of all autoimmune diseases, especially autoimmune thyroiditis. However, we think that experimental and clinical comprehensive studies, which are detailed in sub-groups, should be conducted on this subject.