Men with migraine headaches may be at higher risk of heart disease, including heart attacks, suggests a new study that follows research that produced similar findings for women.

In this week's issue of the Archives of Internal Medicine, Dr. Tobias Kurth of Harvard Medical School and his team report on the results of a study of more than 20,000 men aged 40 to 84 without a history of heart disease who were followed for about 15 years.

"Compared with men who did not report migraine, those who reported migraine were at significantly increased risk of major cardiovascular disease and myocardial infarction," or heart attack, the team concluded.

Migraines are recurring moderate to severe headaches that may be accompanied by visual disturbances, dizziness, nausea, vomiting or sensitivity to light and sound.

About 3.5 million Canadians are believed to suffer from migraines.

In July, researchers reported that women who had migraines with aura — a combination of dizziness, flashes, spots of lights and temporary vision loss before the severe throbbing headaches — may have double the risk of heart disease, compared to women without a history of the headaches.

Migraines as predictive indicator

Of the men in the new study, 1,449, or about seven per cent, reported migraines in the first five years.

After adjusting for age, the incidence of cardiovascular disease per 10,000 men per year was 8.5 for those without migraine and 10.4 for those with migraine —  which Kurth considered a moderate increase in risk, compared to traditional risk factors, such as smoking and high blood pressure.

As for why migraines may increase risk of heart disease, the headaches may be an indicator of a buildup of plaque in the arteries, the study's authors speculated. Migraines are known to trigger inflammatory responses, and inflammation of blood vessels is seen in heart disease.

Also, people who are overweight tend to have more frequent and severe migraines, the researchers said. The increased risk for cardiovascular disease remained after taking known risk factors into account, the researchers added.

Observational studies cannot show a cause-and-effect relationship, and other factors, such as genetics, could also play a role.

Information on whether the migraines were accompanied by aura was unavailable in the men's study.

About 18 per cent of women and six per cent of men have migraines.

The study was funded by the U.S. National Institutes of Health. Kurth and several co-authors reported conflicts of interest associated with pharmaceutical companies, including manufacturers of headache medications.