Patients with Graves' disease have immune systems that mistakenly attack the thyroid. An antibody called thyrotropin receptor antibody causes the thyroid to make excessive amounts of thyroid hormone.

Graves' disease, like many autoimmune disorders, is more common in women than in men.

Graves’ disease typically affects people after the age of 20 and is most likely to strike women during childbearing years. There may be a genetic component to the disease, and stress may play a role in triggering the illness.

Other potential risk factors may include exposure to radioactive iodine.

Graves' ophthalmopathy is a complication of Graves' disease that occurs when tissues behind the eye attract and hold water. This results in a swelling that pushes the eye forward past its protective socket. People who have Graves' disease and smoke cigarettes may be at increased risk of eye problems such as Graves' ophthalmopathy, according to the Centers for Disease Control and Prevention (CDC).