But only minority of migraine sufferers have these visual disturbances, researcher notes
By Amanda Gardner
HealthDay Reporter
TUESDAY, July 18 (HealthDay News) -- Women aged 45 and older who have migraines with aura are at an increased risk for heart attacks, strokes, angina and death due to cardiovascular disease.
However, there was no increased risk for women with a history of migraine without aura, Harvard researchers reported in the July 19 issue of the Journal of the American Medical Association.
"This study confirmed an association between migraine with aura and stroke that was previously identified, and also demonstrated that migraine was a risk factor for ischemic heart disease as well," said Dr. Richard B. Lipton, co-author of an editorial accompanying the study and director of the Montefiore Headache Center in New York City.
"We expanded it beyond ischemic stroke," said study author Dr. Tobias Kurth, an assistant professor of medicine at Harvard Medical School of Public Health in Boston. "The heart part is new, but it's not a different mechanism. It just shows a higher risk of overall cardiovascular disease."
About 18 percent of women and 6 percent of men have migraine in any given year, with some 28 million Americans suffering from the condition.
Migraine headaches are especially severe and can involve nausea, vomiting, sensitivity to light and sound. In some cases, the event also involves an aura -- visual and sensory "warning signs" just before the attack.
Migraines with auras, which comprise the minority of migraine attacks, have already been linked to an increased risk of ischemic stroke. Their association with other cardiovascular problems has not been established.
To evaluate the risk between migraine (with and without aura) with risk of vascular events, the authors looked at data on nearly 28,000 women aged 45 and older who were participating in the Women's Health Study.
Women who reported having active migraine with aura had about double the risk of major cardiovascular disease and heart attacks, almost double the risk for ischemic stroke and a 70 percent higher risk for ischemic cardiovascular death.
This translated into 18 additional major cardiovascular disease events attributable to migraine with aura per 10,000 women per year.
Women who had migraines without aura did not face increased risk in any of these areas. That's good news, since most migraine sufferers do not experience aura.
"It's important to understand that, for most migraine patients, this is not an issue," Kurth said. "Migraine without aura was not associated with any increased risk of vascular events and this is the vast majority of migraine sufferers."
The biological mechanisms linking aura and cardiovascular risk remain unclear.
"There's pretty good evidence that migraine with or without aura have separate genetic risk factors," Lipton explained. "One of the migraine-with-aura genes is associated with elevated levels of high blood pressure and other risk factors. So, one possibility is that there's a genetic link between migraine with aura and heart disease."
For women who do experience aura with their migraines, there are some common-sense strategies.
"Over the last 20 years, there has been an enormous emphasis on knowing your risk factors for heart disease and reducing them," Lipton said. "This study suggests that migraine with aura should be added to that list of risk factors at least in women over 45."
Scientists don't know, however, if treating the migraine itself will decrease the risk.
While researchers search for that answer, women should pay attention to known risk factors.
"Women with migraine with aura should be especially careful about addressing those risk factors that they can modify for heart disease, such as cholesterol and high blood pressure," Lipton said.
"Patients and treating physicians should be particularly cautious about other modifiable risk factors for cardiovascular disease, in particular smoking," Kurth added.
And research needs to confirm the findings in men and in younger women to see if they, too, should heed heightened precautions.
SOURCES: Tobias Kurth, M.D., Sc.D., assistant professor, medicine, Harvard Medical School/Brigham and Women's Hospital, Boston; Richard B. Lipton, M.D., director, Montefiore Headache Center, and professor and vice chairman, department of neurology, Albert Einstein College of Medicine, New York City; July 19, 2006, Journal of the American Medical Association
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