l‐selenomethionine supplementation in children and adolescents with autoimmune thyroiditis: A randomized double‐blind placebo‐controlled clinical trial.

Summary: What is known and objective: Although a beneficial effect of selenium (Se) administration has been proposed in adults with autoimmune thyroiditis (AT), there is a paucity of similar data in children and adolescents. The purpose of the study was to investigate whether administration of a high dose of organic Se (200 μg daily as l‐selenomethionine) has an effect on antithyroid antibody titres in children and adolescents with AT. Methods: Seventy‐one (71) children and adolescents, with a mean age of 11.3 ± 0.3 years (range 4.5‐17.8), diagnosed with AT (antibodies against thyroid peroxidase [anti‐TPO] and/or thyroglobulin [anti‐Tg] ≥60 IU/mL, euthyroidism or treated hypothyroidism and goitre in thyroid gland ultrasonography) were randomized to receive 200 μg l‐selenomethionine or placebo daily for 6 months. Blood samples were drawn for measurement of serum fT4, TSH, anti‐TPO and anti‐Tg levels, and thyroid gland ultrasonography was performed at the entry to the study and after 6 months of treatment. Results and discussion: At the end of the study, a statistically significantly higher reduction in anti‐Tg levels was observed in the Se group compared to the placebo group (Δ: −70.9 ± 22.1 vs −6.7 ± 60.6 IU/mL, P = 0.021). Although anti‐TPO levels were also decreased in the Se group, this change was not statistically different from that of the control group (Δ: −116.2 ± 68.4 vs +262.8 ± 255.5 IU/mL, P = 0.219). No significant difference in thyroid gland volume was observed between the two study groups (P > 0.05). What is new and conclusion: In this original study, organic Se supplementation appears to reduce anti‐Tg levels in children and adolescents with AT. Seventy‐one children and adolescents with autoimmune thyroiditis (AT) were randomized to receive 200 μg L‐selenomethionine (N = 38) or placebo (N = 33) daily for 6 months. Organic Se supplementation appears to reduce anti‐Tg levels in children and adolescents with AT. [ABSTRACT FROM AUTHOR]