Links Between Migraine and Cardiovascular Risk Continue to Evolve

BY CHARLES BANKHEAD
Contributing Writer

LAKE BUENA VISTA, FLA. - (ECCC) Migraine's strong association with cardiovascular risk factors and clinical events mandates careful monitoring and prompt intervention to minimize the inflammatory potential of migraine episodes, said Dr. K. Michael Welch, professor of Neurology at Chicago Medical School in North Chicago, on July 17 at a headache course sponsored by the Diamond Headache Clinic Research and Education Foundation.

The association between migraine and cardiovascular risk factors emerged clearly from a recent analysis of data from the ongoing Genetic Epidemiology of Migraine (GEM) study. A comparison of 620 migraine sufferers and 5,100 individuals with no history of migraine demonstrated significant associations between migraine (particularly with aura) and smoking, unfavorable lipid profile, hypertension, and a history of early-onset coronary heart disease and stroke (Neurology 2005;64:214-20).

"If any doubt remained about the association of migraine with cardiovascular risk factors, this study eliminated it," said Dr. Welch.

The association received additional support from an examination of cardiovascular events in the Women's Health Study. Compared with women who had a negative migraine history, participants with active migraine with aura had a significantly increased risk of major cardiovascular disease, ischemic stroke, myocardial infarction, coronary revascularization, angina, and ischemic cardiovascular death (JAMA 2006;296:283-91).

Multiple investigations have demonstrated a significant link between migraine and stroke, particularly among younger women. The magnitude of stroke risk has ranged as high as sixfold greater in women with a history of migraine with aura.

"In general, studies have shown about a twofold increased risk of stroke in female migraineurs," said Dr. Welch.

The combination of migraine and other known stroke risk factors substantially increases the risk. For example, one study showed that female migraineurs who smoked had a 10-fold greater risk of stroke compared to nonsmokers without a history of migraines. The stroke odds ratio increased to 13.9 for the combination of migraine and use of oral contraceptives (BMJ 1995;310:830-3).

The history, frequency, and type of migraine all influence stroke risk. In a case-control study involving female migraineurs younger than 44, a migraine history exceeding 12 years was associated with an odds ratio of 4.61 for ischemic stroke. Women who had more than 12 episodes of migraine with aura a year had an odds ratio of 10.4 (J Neurol Neurosurg Psychiatry 2002;73:747-50).

Dr. Welch and colleagues have also reported evidence of elevated levels of C-reactive protein in patients with complicated migraine (Headache 2006;46:197-9). The observation suggests that inflammation plays a role in the association between migraine and stroke.

In summarizing the available evidence, Dr. Welch said stroke risk appears to be increased in younger women and men who have migraine with aura. True migraine-induced stroke is a rare clinical phenomenon. The contributions of cardiovascular and migraine risk factors between migraine attacks remain unknown.

"A case can be made for early treatment of acute migraine attacks to diminish the inflammatory potential," said Dr. Welch. "An aggressive attitude toward prevention may warrant consideration."

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