Serum Selenium Levels in Children and Adolescents with Autoimmune Thyroiditis; Low-Dose, Short-Term Selenium Supplementation Effects

Background: Selenium (Se) joins the molecular formation of the enzyme glutathione peroxidase (Gpx), which plays an active role in thyroid metabolism and autoimmune thyroid diseases (AITDs). Objectives: This study aimed to investigate the role of Se deficiency in the etiology of autoimmune thyroiditis and the effect of Se replacement therapy, especially in early-stage diseases. Methods: The study included 54 subclinical hypothyroidism cases. Subclinical hypothyroidism diagnoses were made for cases with elevated thyroid stimulant hormone (TSH) levels and normal sT4 levels. After determining the etiology of subclinical hypothyroidism, cases were categorized into two groups: the first group with autoimmune thyroiditis (n = 28) and the second group without autoimmune thyroiditis (n = 26). Serum Se levels of all patients were examined. Cases with Se deficiency were given oral Se replacement therapy (50 mcg/day for a month). Results: The mean Se level was 64.4 ± 14.19 g/dL in group I and 100.7 ± 20.1 g/dL in group II; there was a remarkably significant difference between the two groups. Group I had notably low Se levels in contrast to high TSH, thyroglobulin autoanti-bodies (anti-TG), and thyroid peroxidase autoantibodies (anti-TPO) levels. There was a negative correlation between Se deficiency and elevated anti-TPO levels. Group II showed a positive correlation between serum Se and free T4 (fT4). Statistically significant regression was observed in anti-TG (P < 0.05) and anti-TPO (P < 0.05) levels three months after oral Se replacement therapy. Conclusions: Selenium replacement might be useful in childhood and adolescents, especially in early stages of autoimmune thyroiditis with low titer antibody elevation.