Migraine is associated with an increased risk of ischemic stroke. The associations are stronger in migraine with aura than in migraine without aura, in women than in men, and in younger subjects. However, the mechanisms by which migraine might increase the risk of ischemic stroke are debated.

We analysed the associations between migraine without aura and migraine with aura and the causes of ischemic stroke in patients aged 18–54 years treated consecutively in a university hospital stroke center.

A total of 339 patients (mean/SD age 43.8/8.8 years, 62.83% male) were included. Migraine with aura was diagnosed in 58 patients, and migraine without aura in 54 patients. Patients with migraine with aura were younger and had fewer traditional cardiovascular risk factors than patients with no migraine. Migraine with aura was strongly associated with atrial fibrillation (odds ratio, 5.08; 95% confidence interval, 1.24–21.92; p = 0.011) and negatively associated with atherosclerosis (odds ratio, 0.29; 95% confidence interval, 0.05–0.97; p = 0.033) and small vessel disease (odds ratio, 0.13; 95% confidence interval, 0.00–0.87; p = 0.022). No other cause of stroke was significantly associated with migraine. The most common cause of stroke was atherosclerosis in no-migraine patients, dissection in migraine without aura patients and patent foramen ovale in migraine with aura patients. Atrial fibrillation was, together with dissection, the second leading cause of stroke in migraine with aura patients, accounting for 10.34% of cases in this subgroup.

We showed that atrial fibrillation was a common cause of ischemic stroke in young adults with migraine with aura.