Migraines With Aura Magnify Stroke Risk Nov. 20, 2002 -- Women who suffer from a migraine with aura are up to 10 times more likely to suffer a stroke, according to a new study.

Auras affect about 15% of the estimated 28 million Americans who suffer from migraine headaches, according to the National Headache Foundation. Auras usually precede the impending headache by up to an hour and may come in the form of vision problems, such as bright or flashing dots, blind spots, or distorted vision, or other sensory disturbances.

Although previous research has already linked migraine to an increased risk of stroke, researchers say this is one of the first studies to look at whether the type of migraine, age of onset, and attack frequency affect the risk of stroke among women.

The findings appear in the December issue of the Journal of Neurology, Neurosurgery and Psychiatry.

The researchers compared 86 women who had a stroke caused by a blockage of the blood supply to the brain to more than 200 women who were admitted to the hospital for other reasons. These clot-related strokes -- called ischemic strokes -- account for more than 80% of all strokes.

They found that the risk of stroke was four times higher in women who had migraines for more than 12 years. But the risk was even higher among women who had migraines with auras.

Women whose first migraine was accompanied by aura were eight times more likely to suffer a stroke. And the risk was 10 times higher among women who continued to have migraines with aura more than once a month.

The age at which the women began having migraines did not seem to affect stroke risk.

Although the heightened risk associated with migraine is significant, lead researcher Michael Donaghy, MD, stresses that strokes are still very rare among women in this age group -- about 15 strokes per 100,000 women. Donaghy is with the department of clinical neurology at Radcliffe Infirmary in Oxford, U.K.

Even so, experts say this study provides yet another reason for migraine sufferers to get proper treatment in order to prevent and reduce the frequency of the attacks.