By Ed Edelson
WEDNESDAY, Feb. 10 (HealthDay News) -- People with migraines are more likely to have heart attacks, a new study shows, but the exact reason why the two conditions are linked is still unclear.
The incidence of heart attacks in people with migraine is almost double that of people who don't suffer the headaches, according to a report in the Feb. 10 online edition of Neurology by a group including Dr. Richard B. Lipton, a professor of neurology at Albert Einstein College of Medicine in New York City.
The study, which compared 6,102 people with migraine and 5,243 without the headaches, found a 4.1 percent incidence of heart attacks in the migraine patients, compared with 1.9 percent in those without the debilitating headaches.
Previous studies have found an association between migraine and cardiovascular problems including heart problems and stroke, Lipton noted. One study, which looked at only women, found an increased incidence of stroke, especially for migraine with the visual disturbances called aura (women are up to four times more likely than men to have migraines). Another study, which looked only at men, found an increased risk of heart disease.
"The strength of this study is that we have a very large number of migraine sufferers, data to distinguish between migraine with and without aura, and longitudinal data on men and women in the same study," Lipton said.
The new study did find a higher incidence of heart attack for migraine with aura -- three times that of the migraine-free group. It also found that people with migraine were more likely to have the classic risk factors for heart attack, stroke and other cardiovascular problems: diabetes (12.6 percent versus 9.4 percent), high blood pressure (33.1 percent versus 27.5 percent) and high cholesterol (32.7 percent versus 25.6 percent).
But those risk factor differences did not account for the increased migraine-associated risk, Lipton noted. "The risk remains elevated even after we adjust for the known cardiovascular risk factors," he said. "There have been suggestions of a genetic link, but the nature of the link is not entirely clear."
Even so, Lipton added, "Cardiovascular risk reduction is important for everybody. If you have migraine, it might be more important for you than for the general population. They should be particularly vigilant about controlling body weight, keeping blood pressure low, modifying all the risk factors that are within their control."
Studies are underway to see whether better control of migraine can reduce the cardiovascular risk, said Lipton, who is conducting one such study. "That is something we don't know yet," he stated. "But if you have four or five disabling migraine days a month, it makes sense to take the medications that control them. If they reduce the risk of heart attack and stroke, so much the better."
Results of those studies are expected "over the next couple of years," Lipton said.
Cardiologists, especially those who treat women, should pay attention to those results and the current study, even though they appear in a neurology journal, said Dr. Holly Andersen, director of the Ronald O. Perelman Heart Institute at New York-Presbyterian/Weill Cornell Medical Center in New York City.
"Clearly, the majority of people who have migraines are women, often young women," Andersen said. "This is a marker that might help prevent cardiac disease. There have been several large population studies that show women with migraines have an increased risk of cardiovascular events. These are the women we should be intervening with. If they use oral contraceptives there should be a concern, because they can form blood clots, particularly if they smoke."
And since the risk of stroke in women who have migraine is clear, "it's not too much of a stretch to think they have a threat with heart disease," said Dr. Dara Jamieson, director of the headache center at New York-Presbyterian/Weill Cornell. "But this is an observational study that needs to be expanded to get a better understanding of mechanisms," Jamieson added.
Migraine and its treatment are described by the U.S. National Library of Medicine.