Stroke Risk Higher in Young Adults with Thyroid Condition

Young adults with an overactive thyroid face a 44% increased risk of stroke compared to those with normal thyroid function, according to a new study.

Researchers at Taipei Medical University (Taiwan) reviewed medical records in a large database collected by Taiwan's national health insurance program, and identified a total of 3,176 patients with hyperthyroidism and 25,408 patients without hyperthyroidism who were included as comparison cohort (average age 32 years). Each patient was individually tracked for five years from their index ambulatory visit to identify those in whom ischemic stroke developed. Cox proportional hazard regressions were performed to compute the 5-year stroke-free survival rate between the two cohorts.

The researchers found that during those five years, 198 of the 28,584 patients developed ischemic stroke (0.7%), including 31 (1%) of the hyperthyroidism patients and 167 (0.6%) of the comparison group. After adjusting for factors including patient age, gender, income, level of urbanization, high blood pressure, diabetes, atrial fibrillation (AF), high cholesterol, coronary heart disease (CHD), and whether they were taking medication to treat heart rhythm problems, the risk of having a stroke during the five-year follow-up period was 44% higher for patients with hyperthyroidism than for those without it. The study was published ahead of print on April 1, 2010, in Stroke.

"Hyperthyroidism may be associated with various syndromes or conditions linked to cerebrovascular disease in young adults,” said senior author Professor Herng-Ching Lin, Ph.D., of the school of health care administration. "A more thorough evaluation in future studies may help elucidate the causes of stroke in this age group. Our results indicate a need for thyroid function testing and detection of hyperthyroidism in surveys to identify the causes of ischemic stroke in young people.”

Hyperthyroidism is a term describing overactive tissue within the thyroid gland, resulting in overproduction, and thus an excess, of the circulating free thyroid hormones thyroxine (T4), triiodothyronine (T3), or both; the increased hormone levels speed up the body's metabolism, causing symptoms such as sweating, weight loss, diarrhea, and nervousness. Hyperthyroidism is a common endocrine disorder that affects an estimated 0.5% to 2% of the world's population, including a significant group of young adults.

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