Objective: to assess the effect of selenium therapy on primary autoimmune hypothyroidism
Design: randomized controlled trial
Setting: the eligible patients with primary autoimmune hypothyroidism who refer to endocrinology clinic of Shahid Beheshti hospital in 2012 will be enrolled
Inclusion criteria: (a) age of 18 to 75 years; (b) having primary autoimmune hypothyroidisms; (c) having anti-TPO >200 U/ml
Exclusion criteria: (a) history of Thyroid surgery; (b) history of thyroid cancer; (c) hypothyroidism resulted from hyperthyroidism; (d) history of auto-immune disease and known rheumatologic diseases; (e) pregnancy; (f) renal failure; (g) subclinical hypothyroidism; (h) history of using radioactive iodine, anti thyroid medication, cytotoxic; immunosuppressive, glucocorticoid, amiodaron, lithium, interferon, and chemotherapy
Intervention: 20 patients with primary autoimmune hypothyroidism will receive levothyroxine plus selenium tablet 200 microgram once a day for three months
Control: 20 patients with primary autoimmune hypothyroidism will receive levothyroxine only for three months
Primary outcome: measurement of anti-TPO titer after three months
Secondary outcome: measurement of (a) TSH, T3 and T4 titers after three months; (b) any adverse effect such as dizziness, abdominal pain, tremor, sweating, hair loss, sensation of smell of garlic