BackgroundMigraine carries risk of myocardial infarction (MI) and stroke. The risk of premature MI (i.e., among young adults) and stroke differs between men and women; previous studies indicate that migraine is mainly associated with an increased risk of stroke among young women. The aim of this study was to examine impact of migraine on the risk of premature (age ≤60 years) MI and ischemic/hemorrhagic stroke among men and women.Methods and findingsUsing Danish medical registries, we conducted a nationwide population-based cohort study (1996 to 2018). Redeemed prescriptions for migraine-specific medication were used to identify women with migraine (n =179,680) and men with migraine (n= 40,757). These individuals were matched on sex, index year, and birth year 1:5 with a random sample of the general population who did not use migraine-specific medication. All individuals were required to be between 18 and 60 years old. Median age was 41.5 years for women and 40.3 years for men.The main outcome measures to assess impact of migraine were absolute risk differences (RDs) and hazard ratios (HRs) with 95% confidence intervals (CIs) of premature MI, ischemic, and hemorrhagic stroke, comparing individuals with migraine to migraine-free individuals of the same sex. HRs were adjusted for age, index year, and comorbidities. The RD of premature MI for those with migraine versus no migraine was 0.3% (95% CI [0.2%, 0.4%];p< 0.001) for women and 0.3% (95% CI [−0.1%, 0.6%];p= 0.061) for men. The adjusted HR was 1.22 (95% CI [1.14, 1.31];p< 0.001) for women and 1.07 (95% CI [0.97, 1.17];p= 0.164) for men. The RD of premature ischemic stroke for migraine versus no migraine was 0.3% (95% CI [0.2%, 0.4%];p< 0.001) for women and 0.5% (95% CI [0.1%, 0.8%];p< 0.001) for men. The adjusted HR was 1.21 (95% CI [1.13, 1.30];p< 0.001) for women and 1.23 (95% CI [1.10, 1.38];p< 0.001) for men. The RD of premature hemorrhagic stroke for migraine versus no migraine was 0.1% (95% CI [0.0%, 0.2%];p= 0.011) for women and −0.1% (95% CI [−0.3%, 0.0%];p= 0.176) for men. The adjusted HR was 1.13 (95% CI [1.02, 1.24];p= 0.014) for women and 0.85 (95% CI [0.69, 1.05];p= 0.131) for men.The main limitation of this study was the risk of misclassification of migraine, which could lead to underestimation of the impact of migraine on each outcome.ConclusionsIn this study, we observed that migraine was associated with similarly increased risk of premature ischemic stroke among men and women. For premature MI and hemorrhagic stroke, there may be an increased risk associated with migraine only among women.