Study: Migraines with vision loss increase stroke risk

Women who suffer from a loss of vision while experiencing migraine headaches have a 70% increase in stroke risk compared to women who don't have migraines at all, researchers reported at the American Heart Association's annual International Stroke Convention.

The study was conducted by researchers at the University of Maryland School of Medicine in Baltimore. It compared the stroke risk associated with suffering from migraine headaches that are accompanied by a loss of vision, migraines that cause the sufferer to see lines or spots, and not suffering migraines at all.

An estimated 17% of Canadians suffer from migraines, severe headaches caused when blood vessels in the lining of the brain swell. Triggers vary from person to person, but can include hormonal changes and menstruation, certain foods, and stress. Vision problems and hearing abnormalities often precede these headaches.

"Our study found that women who suffer migraines with loss of vision or partial loss of vision were 1.7 times more likely to have stroke compared with women who do not have a history of migraines," Dr. Wayne H. Giles, an author of the study and the associate director for science in the Division of Adult and Community Health at the Centers for Disease Control and Prevention, said in a statement released by the American Heart Association.

Women who saw spots or lines had just a 25% increase in stroke risk over women who don't have migraines, the researchers said. Women who suffer migraines with no visual symptoms did not have an increased stroke risk.

The study, which included 963 women between the ages of 15 and 49, is the first to differentiate between the type of visual symptom and its effect on stroke risk. Other studies have linked visual symptoms to an increased risk, but did not explore the difference between various visual effects. More than 90% of migraine sufferers do experience visual symptoms, the researchers said.

A separate study also presented at the conference examined 238 male and female stroke patients between the ages of 16 and 44 and a control group of equal size to determine whether migraines increased the risk of stroke.

The researchers compared the stroke-sufferers to the control group on a number of criteria, including migraine history, wine consumption, smoking, use of birth control pills, blood pressure, and cardiac rhythm.

Analysis of the data showed that the migraine sufferers had 2.7 times the risk of stroke compared to the control group. Migraine sufferers who also had high blood pressure were almost nine times more likely to be at risk for stroke. Use of birth control pills, wine consumption, and smoking did not differ between the stroke and control groups.

Because of the increased stroke risk, researchers urged migraine sufferers to minimize other risk factors as much as possible by quitting smoking, controlling blood pressure, losing weight if necessary, and weighing the risks and benefits of using oral contraceptives.