By Kathleen Doheny
Exactly what triggers these vessel tears is not clear, the researchers added.
However, study author Dr. Alessandro Pezzini stressed that the probability that migraine sufferers would develop this condition -- called arterial dissection -- is still quite low.
"Overall, migraine is a benign condition in the great majority of affected individuals," said Pezzini, a professor of neurology at the Universita degli Studi di Brescia in Italy.
Of the nearly 2,500 stroke patients studied, aged 18 to 45, only 13 percent had strokes related to neck artery tears. This group was more likely to have high cholesterol, diabetes or be current smokers.
Aura describes sensory changes -- such as flashes of light, other vision disturbances or tingling of hands or face -- that can occur before or during a migraine.
Compared to patients who had migraine with aura, those who had migraine without aura were 1.7 times more likely to have the artery tears. The findings showed that artery tears and strokes were also more likely to occur in men and in patients aged 39 and younger.
The study did have limitations, the researchers said. The investigators did not have information on how frequent or severe the migraines were, or how often the auras occurred.
And the study was observational, so "we cannot say anything about the existence of a cause-and-effect relationship between migraine and arterial dissection," Pezzini said.
Nor can the researchers explain the link, but they can speculate. The two disorders may have a common genetic basis, Pezzini said. Or an underlying abnormality may predispose a person to both the blood vessel problem and the stroke.
The findings were published online March 6 in the journal JAMA Neurology.
While previous studies have found a link between migraines and artery tears, the new findings are stronger because of the large number of people studied, said Dr. Patrick Lyden, chair of neurology at Cedars-Sinai Medical Center in Los Angeles. He wrote an editorial to accompany the study.
The type of tear evaluated in the study is not rare, Lyden said, but it is not common. "The incidence is about five of 100,000, roughly half that of multiple sclerosis [patients] for comparison."
No triggering event is ever found for the tears in about half of cases, Lyden said. But he added, "the mechanism is often trauma, such as whiplash, incorrectly applied chiropractic manipulation or a sports-related neck-stretching accident."
Lyden advises migraine patients to avoid risky activities. That means no chiropractic neck manipulation, he said.
"If you go to the gym, avoid profound heavy lifting. Should you suffer an accident -- such as whiplash or sports-related injury -- and you have neck pain, take an aspirin -- it's a mild blood thinner. If you have neurological symptoms that could be a warning of stroke, come to an [emergency room] immediately."
Everyone should be aware of stroke warning signs, Lyden said. Remember the acronym FAST: face; arm; speech; and time. Any asymmetry of the face, weakness in one arm or change in speech (such as slurring or using incorrect words) are cause for concern.
And time is brain: Make a note of when the symptoms started, Lyden said, and go to a stroke center or call 9-1-1.