Clinical research study
Migraine Headache and Ischemic Stroke Risk: An Updated Meta-analysis

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Abstract

Background

Observational studies, including recent large cohort studies that were unavailable for prior meta-analysis, have suggested an association between migraine headache and ischemic stroke. We performed an updated meta-analysis to quantitatively summarize the strength of association between migraine and ischemic stroke risk.

Methods

We systematically searched electronic databases, including MEDLINE and EMBASE, through February 2009 for studies of human subjects in the English language. Study selection using a priori selection criteria, data extraction, and assessment of study quality were conducted independently by reviewer pairs using standardized forms.

Results

Twenty-one (60%) of 35 studies met the selection criteria, for a total of 622,381 participants (13 case-control, 8 cohort studies) included in the meta-analysis. The pooled adjusted odds ratio of ischemic stroke comparing migraineurs with nonmigraineurs using a random effects model was 2.30 (95% confidence interval [CI], 1.91-2.76). The pooled adjusted effect estimates for studies that reported relative risks and hazard ratios, respectively, were 2.41 (95% CI, 1.81-3.20) and 1.52 (95% CI, 0.99-2.35). The overall pooled effect estimate was 2.04 (95% CI, 1.72-2.43). Results were robust to sensitivity analyses excluding lower quality studies.

Conclusions

Migraine is associated with increased ischemic stroke risk. These findings underscore the importance of identifying high-risk migraineurs with other modifiable stroke risk factors. Future studies of the effect of migraine treatment and modifiable risk factor reduction on stroke risk in migraineurs are warranted.

Section snippets

Search Strategy

We performed a systematic literature search of MEDLINE (using PubMed) and EMBASE for relevant published reports from the beginning of indexing for each database through February 2009. We also searched the National Library of Medicine's Health Services Research Projects in Progress, National Institute of Health's clinical trials registry, World Health Organization's International Clinical Trials Registry Platform, Cochrane Central Register of Controlled Trials, Open System for Information on

Literature Search

The search strategy retrieved 2287 citations: 1275 from PubMed, 1009 from EMBASE, and 3 from the Grey Literature (Figure 1). Hand searching of bibliographic references identified 2 additional articles, leaving 1799 unique articles for screening of titles or abstracts. Of 35 articles evaluated by full-text review, 21 studies were eligible for final inclusion in the meta-analysis.

Study Characteristics

Characteristics of the 21 selected studies are shown in Table 1, Table 2.9, 10, 11, 12, 18, 19, 20, 21, 22, 29, 30, 31

Discussion

We report the largest meta-analysis to date of the association between migraine and stroke. In this meta-analysis of 21 observational studies of the association of migraine headache and ischemic stroke, migraine was independently associated with a 2-fold increased risk of ischemic stroke.

There are several potential mechanisms for the increased risk of ischemic stroke in migraineurs. Migraine may increase ischemic stroke risk via vasospasm-induced cerebrovascular hypoperfusion,42 platelet

Conclusion

Migraines appear to be independently associated with a 2-fold increased risk of ischemic stroke. Migraine is a potentially modifiable risk factor that can be treated,58 and stroke risk can be reduced through reduction of other risk factors.5 Therefore, further study is warranted to assess the effects of migraine control and stroke risk factor reduction on the risk of ischemic stroke in migraineurs.

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  • Cited by (0)

    Funding: Dr. Kahn is a recipient of a National Career Scientist Award from the Fonds de la Recherche en Santé du Québec. Dr. Nazarian is funded by the Johns Hopkins Richard S. Ross Clinician Scientist Award, the PJ Schafer Memorial Research Award, and the National Institutes of Health Clinical Research Scholars Program (1KL2RR025006-01). We did not receive any additional funding, including pharmaceutical industry funds, for the preparation of this manuscript or any related research.

    Conflict of Interest: All authors report no conflicts of interest.

    Authorship: All authors had access to the data and a role in writing the manuscript.

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