Selenium Supplementation Versus Placebo in Patients With Graves' Hyperthyroidism

GRAves Selenium Supplementation Trial (GRASS) - an Investigator-initiated Randomised, Blinded, Multicentre Clinical Trial of Selenium Supplementation Versus Placebo in Patients With Graves' Hyperthyroidism

The purpose of this study is to investigate if selenium supplementation to the standard treatment with anti-thyroid drugs in patients with Graves' hyperthyroidism, will lead to a fewer people with anti-thyroid treatment failure and faster remission, in terms of better quality of life during the first year of treatment and more patients staying in remission.

Inclusion Criteria:

• Age 18 years or older.
• Active Graves' hyperthyroidism (suppressed TSH (< 0.1) and positive TRAb) measured within the last two months prior to the inclusion date.
• Written informed consent

Exclusion Criteria:

• Major co-morbidity, making the participants unlikely to continuously receive trial intervention in the intervention period.
• Previous treatment with radioactive iodine.
• Current ATD treatment having been received for more than two months.
• Treatment with immunomodulatory drugs, such as cyclosporine A, methotrexate, cyclophosphamide.
• Allergy towards the components in the selenium and placebo pills.
• Pregnant or breast-feeding women.
• Intake of selenium supplementation above 70 µg per day (70 µg corresponds to the amount in a multivitamin tablet).
• Unable to read and understand Danish.
• Lack of informed consent