Young adults with overactive thyroid face a higher risk of stroke compared to those with normal thyroid function.

Strokes of undetermined cause account for between one-third and one-fourth of all ischemic strokes in young people. Hyperthyroidism, also known as overactive thyroid, is a common endocrine disorder that affects an estimated one in 200 people to one in 50 people of the world's population, including a significant group of young adults. The condition causes overproduction of thyroid hormone, which speeds up the metabolism and causes symptoms such as sweating, weight loss, diarrhoea and nervousness. Hyperthyroidism has never been considered as a potential risk factor for stroke in the 18 - 44 age group.

To estimate the risk for ischemic stroke among young hyperthyroidism patients, researchers compared 3176 patients with hyperthyroidism with 25,408 patients without hyperthyroidism.  The patients' average age was 32 years.

During the follow-up of five years, 198 patients had ischemic strokes; 31 people with hyperthyroidism and 167 patients without hyperthyroidism.  After adjusting for the patient's age, gender, income, level of urbanisation, hypertension, diabetes and other risk factors for stroke, the risk of having ischemic stroke was found to be almost twice as high for patients with hyperthyroidism than for patients in the comparison group.

The findings indicate that hyperthyroidism is associated with a higher risk for ischemic stroke among young adults.