Background: Migraine has been associated with risk of cardiovascular disease (CVD). Data on the association between migraine frequency and CVD are sparse.
Methods: Prospective cohort study of 27,798 US women aged >or=45 years, who were free of CVD, and for whom we had information on lipids and migraine frequency. We categorized migraine frequency as < monthly, monthly, and >or= weekly. Incident CVD was confirmed after medical record review.
Results: Of the 3,568 women with active migraine at baseline, 75.3% reported a migraine frequency of < monthly, 19.7% monthly, and 5.0% >or= weekly. During 11.9 years of follow-up, 706 CVD events occurred. Compared with women without migraine, the multivariable-adjusted hazard ratios (HRs) (95% confidence intervals) among active migraineurs for CVD were 1.55 (1.22-1.97), 0.65 (0.31-1.38), and 1.93 (0.86-4.33) for an attack frequency of < monthly, monthly, and >or= weekly, respectively. The association between migraine frequency and CVD was only apparent among migraineurs with aura. Among those, the multivariable-adjusted HRs for women with a migraine frequency < monthly ranged from 1.81 (1.30-2.50) for coronary revascularizations to 2.43 (1.58-3.74) for myocardial infarction. For women with active migraine with aura and migraine frequencies of >or= weekly, we only found significant increased risk of ischemic stroke (HR = 4.25 [1.36-13.29]).
Conclusions: In our data, the association between migraine and cardiovascular disease varies by migraine frequency. Significant associations were only found among women with migraine with aura. Ischemic stroke was the only outcome associated with a high-attack frequency while a low-attack frequency was associated with any vascular event. Low number of outcome events should caution the interpretation.