SAN FRANCISCO — The suggestion that women who have migraine with aura are at increased risk for significant cerebral and coronary vessel disease gained strength from three presentations given during the 32nd International Stroke Conference.
Leah MacClellan presented data, discussed in detail below, suggesting that women who have migraine with aura may be at increased risk for ischemic stroke. In a separate presentation, Dr. Tobias Kurth reported on an association in women between the presence of migraine with aura and an increased risk for hemorrhagic stroke. (See related story, p. 19.)
Dr. Kurth's finding was consistent with data he reported in 2006 at the annual meeting of the American Academy of Neurology showing that migraine with aura seems to increase the risk for coronary artery disease and myocardial infarction (CLINICAL NEUROLOGY NEWS, May 2006, p. 1). A third presentation by Dr. Dulka Manawadu showed an increased stroke risk among women younger than 35 years with migraine and aura who took oral contraceptives. (See related story, p. 19.)
During her presentation, Ms. MacClellan reported findings from her population-based case-control study of 386 women aged 15–49 years who presented with a first, nontraumatic ischemic stroke, and 614 controls matched for age, race, and region. The investigators stratified the odds of stroke among women with a history of migraine with aura, compared with women with no history of migraine, by the presence of hypertension, diabetes, or myocardial infarction. The associations were strongest among those with no history of these classic stroke risk factors, Ms. MacClellan explained at the conference, which was sponsored by the American Stroke Association.
For example, the odds ratio for stroke in those with migraine plus aura vs. those with no history of migraine was 0.8 in those with hypertension, compared with 1.7 for those without hypertension; 1.2 in those with diabetes, compared with 1.5 in those without diabetes; and 0.2 in those with a history of MI, compared with 1.6 in those with no history of MI, said Ms. MacClellan of the University of Maryland, Baltimore. All associations were statistically significant.
A similar analysis stratifying stroke risk based on current smoking and oral contraceptive use in women with migraine plus aura, compared with women with no history of migraine, showed the associations between migraine with aura and stroke were the same regardless of smoking or OC use. However, the interaction between smoking and OC use was shown to be important. Compared with women with migraine plus aura alone, those who smoked and had migraine plus aura had a significant 2.3-fold increased risk of stroke, as did those with migraine plus aura who used OCs. Women with migraine plus aura who smoked and also used OCs had a significant 7.3-fold increase in the odds of stroke.
Another finding of note from this study was that onset of migraine with aura in the past year was associated with increased stroke risk. Those with onset in the past year, compared with those with no history of migraine, had a significant 6.7-fold increased risk of stroke. Those with a migraine history of more than 12 years had a non-statistically significant 1.4-fold increase in stroke risk. This finding contrasts with findings from at least one other study showing that long-term stroke history was associated with increased stroke risk, she said.
There was no evidence in the current study of a role for patent foramen ovale in mediating the association between migraine with aura and stroke, nor was there evidence for preferential infarct location in terms of anterior and posterior circulation in those with migraine plus aura.
Patients were identified from discharge data from 59 hospitals, and all had CT- or MRI-confirmed stroke. Controls were ascertained by random digit dialing. Migraine with aura was defined as headache with aura at least twice per year, with spots, lines, flashing lights, or loss of vision around the time of the headache. Migraine without aura was defined as at least five headaches per year with nausea, vomiting, or sensitivity to light during headache, and no history of visual aura.
Migraine with aura was reported by 38% of patients and 29% of controls. The percentage with migraine without aura was similar in the two groups; thus the current analysis focused only on migraine with aura.
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