Migraine and risk of hemorrhagic stroke: a study based on data from general practice

We investigated the association between hemorrhagic stroke and migraine using data from The Health Improvement Network database. We ascertained 1,797 incident cases of intracerebral hemorrhage (ICH) and 1,340 of subarachnoid hemorrhage (SAH). Density-based sampling was used to select 10,000 controls free from hemorrhagic stroke. Using unconditional logistic regression models, we calculated the risk of hemorrhagic stroke associated with migraine, adjusting for age, sex, calendar year, alcohol, body mass index, hypertension, previous cerebrovascular disease, oral contraceptive use, and health services utilization. The risk (odds ratio [OR]) of ICH among migraineurs was 1.2 (95% confidence interval [CI] 0.9-1.5), and of SAH was (1.2, 95% CI 0.9-1.5). The association with ICH was stronger for migraine diagnosed a parts per thousand yen20 years prior to ICH (OR 1.6, 95% CI 1.0-2.4), but not with SAH (OR 1.1, 95% CI 0.6-2.1). In analyses stratified by migraine type and gender, the OR of ICH in women with migraine with aura was 1.7 (95% CI 0.9-3.4) and the corresponding OR of SAH in women was 1.2 (95% CI 0.6-2.3). No clear increased risk of ICH or SAH was observed in migraineurs.