Selenium treatment in autoimmune thyroiditis: 9-month follow-up with variable doses

    1. Omer Turker,
    2. Kamil Kumanlioglu1,
    3. Inanc Karapolat2 and
    4. Ismail Dogan
    1. Thyroidology Unit, Department of Nuclear Medicine, GATA Haydarpasa, Istanbul, Turkey
    2. 1Department of Nuclear Medicine, Faculty of Medicine, Ege University, Izmir, Turkey
    3. 2Department of Nuclear Medicine, Sifa Hospital, Izmir, Turkey
    1. (Requests for offprints should be addressed to O Turker; Email: otturker{at}


    The aim of this study is to investigate the long-term (9 months) effects of variable doses (200/100 μg/day) of l-selenomethionine on autoimmune thyroiditis (AIT) and the parameters affecting the success rate of this therapy. The present study was designed in three steps: (1) 88 female patients with AIT (mean age = 40.1 ± 13.3 years) were randomized into two groups according to their initial serum TSH, thyroid peroxidase antibody (TPOAb) concentrations, and age. All the patients were receiving l-thyroxine to keep serum TSH ≤2 mIU/l. Group S2 (n = 48, mean TPOAb = 803.9 ± 483.8 IU/ml) received 200 μg l-selenomethionine per day, orally for 3 months, and group C (n = 40, mean TPOAb = 770.3 ± 406.2 IU/ml) received placebo. (2) 40 volunteers of group S2 were randomized into two age- and TPOAb-matched groups. Group S22 (n = 20) went on taking l-selenomethionine 200 μg/day, while others (group S21) lowered the dose to 100 μg/day. (3) 12 patients of group S22 (group S222) went on taking l-selenomethionine 200 μg/day, while 12 patients of group S21 (S212) increased the dose to 200 μg/day. Serum titers of TPOAb decreased significantly in group S2 (26.2%, P < 0.001), group S22 (23.7%, P < 0.01) and group S212 (30.3%, P < 0.01). There were no significant changes in group C and group S222 (P > 0.05). TPOAb titers increased significantly in group S21 (38.1%, P < 0.01). A significant decrease in thyroglobulin antibody titers was only noted in group S2 (5.2%, P < 0.01). l-selenomethionine substitution suppresses serum concentrations of TPOAb in patients with AIT, but suppression requires doses higher than 100 μg/day which is sufficient to maximize glutathione peroxidase activities. The suppression rate decreases with time.

    (O Turker is now at Akademi Medical Centre, Mimar Sinan Mah. 1359 sokak, No. 4A Kyzylkanat Sitesi, Alsancak, Izmir, Turkey)

    • Received in final form 18 March 2006
    • Accepted 7 April 2006
    • Made available online as an Accepted Preprint 27 April 2006
    • Accepted Preprint first posted online on 27 April 2006
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