Italian study results just released demonstrate that Migraineurs are more likely to experience a headache before the onset of a stroke than patients without Migraine disease.
  

Study Methods

In this case-control study*, 96 acute stroke patients with a lifetime history of migraine (M+) and 96 stroke patients without (M-) were selected and headache attributed to acute ischemic stroke (stroke cause by blocked blood vessel) was analyzed.

Study Results

• In the M+ group, a higher prevalence of headache preceding stroke than in the M- group.
• In the M+ group, the headache preceding stroke more often had Migraine features.
• In the M- group, headache rarely occurred. This headache, when it occurred, was usually accompanied by other neurological signs of stroke and more frequently had the features of tension-type headache.
• M+ participants experienced more strokes in the brainstem than M- participants/
• 66% of participants with stroke located in the brainstem experienced headaches with Migraine features before the onset of stroke.
• Although the researchers expected to find a higher incidence of stroke in the M+ group than the M- group, they did not. They state that this may be because they had more M+ patients who had Migraine with aura (MwA) patients than Migraine without aura (MwoA) and MwA has been shown to be associated with increased risk of stroke during and outside of Migraine attacks.

The researchers note a disadvantage of the study:

"Finally, the major disadvantage of the case–control study should also be remembered. This consists in the fact that observed rates cannot be used as estimates of the absolute risk, while taking into account the potential confounding related to the nature of case–control studies. Data from outside the case–control study design, such as those from a large series of stroke patients, could help to better define the frequency of headache in stroke patients in general, and in relation to a previous lifetime history of migraine, in particular."¹
  

Summary and Comments

In this study, nearly 80% of the M+ participants experienced a headache in the 24-hour period before the onset of stroke, suggesting that, "cerebral ischemia lowers the threshold for head pain more easily in these 'susceptible' patients."¹

In this study, the researchers detected a higher incidence of stroke in the brainstem in M+ participants. On this point, Sarchielli commented,

"The more frequent involvement of brainstem in migraineur patients with ischemic infarction supports the hypothesis that vascular events preceding the clinical stroke...can cause a dysfunction of this structure, which may be more predisposed to be abnormally activated."²

It's important to note that this study examined the frequency of headache prior to stroke. It was not designed to draw any conclusions regarding any increased risk of stroke among Migraineurs.

* A case-control study is a study that compares two groups of people: those with the disease or condition under study (cases) and a very similar group of people who do not have the disease or condition (controls). Researchers study the medical and lifestyle histories of the people in each group to learn what factors may be associated with the disease or condition. For example, one group may have been exposed to a particular substance that the other was not. Also called retrospective study. (definition from the National Cancer Institute.) In this study, the Migraineurs were the cases; the non-Migraineurs were the controls.

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Resources:

¹ Nardi, Katiuscia, MD; Parnetti, Lucilla, MD, PhD; Pieri, Maria L. MD; Eusebi, Paolo, PhD; Calabresi, Paolo, MD; Sarchielli, Paola, MD. "Association Between Migraine and Headache Attributed to Stroke:? A Case-Control Study." Headache 2008;48:1468-1475. doi: 10.1111/j.1526-4610.2008.01137.x

² Reuters Health. "Headache before stroke more common in migraineurs." Reuters News. New York. December 31, 2008.
  

© Teri Robert, 2009.
Last updated January 4, 2009.