Hyperthyroidism and risk of ischemic stroke in young adults: a 5-year follow-up study.

BACKGROUND AND PURPOSE Case reports or case series have reported the association between hyperthyroidism and cerebrovascular disease. However, hyperthyroidism has never been considered as a potential risk factor for stroke in young people. The aim of the present study is to estimate the risk for ischemic stroke among hyperthyroidism patients aged 18 to 44 years during a 5-year period after the diagnosis of hyperthyroidism as compared to a cohort of patients without hyperthyroidism during the same period. METHODS A total of 3176 patients with hyperthyroidism were included as the study cohort and 25 408 patients without hyperthyroidism were included as comparison cohort. Each patient was individually tracked for 5 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 these 2 cohorts. RESULTS Of the total sample of 28 584 patients, 198 patients (0.7%) had ischemic strokes during the 5-year follow-up period (31 [1.0% of the hyperthyroidism patients] from the study cohort and 167 [0.6% of comparison patients] from the comparison cohort). After adjusting for the patient's age, gender, income, level of urbanization, hypertension, diabetes, atrial fibrillation, hyperlipidemia, coronary heart disease, and whether they were using antiarrhythmics, the hazard of having ischemic stroke during the 5-year follow-up period was 1.44-times greater (95% CI, 1.02-2.12; P=0.038) for patients with hyperthyroidism than for patients in the comparison cohort. CONCLUSIONS We conclude that hyperthyroidism is associated with an increased risk for ischemic stroke among young adults.