TUESDAY, Nov. 13 (HealthDay News) -- Women who suffer from migraines are more likely to have brain lesions than those who don't get the debilitating headaches, but new MRI research shows that the severity of those lesions does not correlate with greater memory or thinking problems.
"We found a higher volume of brain changes among women with migraines, but no evidence of a strong relationship between the attack rate or other related factors with the degree of lesions," said study author Dr. Mark Kruit, a neuroradiologist at Leiden University Medical Center in the Netherlands.
The brain changes, also called "white matter hyperintensities," are believed to be caused by episodes of low oxygen to the cells, called ischemia. The lesions are associated with higher risk of atherosclerotic disease, ischemic stroke and cognitive decline, according to the researchers.
"From a broad perspective, we should probably understand migraines as a problem related to coronary artery disease," Kruit said. "The white matter hyperintensities are likely of ischemic origin, but we need further studies."
The study was published Nov. 14 in the Journal of the American Medical Association.
About 12 percent of people in the United States get migraines, which are recurring attacks of moderate to severe throbbing or pulsing head pain, according to the U.S. National Library of Medicine. They are three times more common in women than in men.
As for why women are more prone to migraines than men, Kruit explained that previous studies implicate the female hormone estrogen.
The researchers developed this study to follow up on work published in 2004, Kruit said. "[That study] had a scary message: that females with migraines had more brain damage, and the researchers had no clue why they were seeing brain lesions," he explained. "They said that people with higher migraine attack frequency had more lesions, suggesting causation."
The researchers wanted to determine whether women or men who had migraines had a higher incidence of brain changes nine years after having an initial MRI. Tapping 286 people from the Netherlands who had participated in the previous study, the scientists gave MRIs to people with migraines and to those without the headaches, accounting for age, gender, hypertension, diabetes and educational level.
The participants in the migraine group had an average age of 57 years old, and 71 percent were women. Those in the control groups were an average of 55 years old, and 69 percent were women.
The researchers found that 77 percent of the women with migraines and 60 percent of the control group showed progression of white matter hyperintensities. The women with migraines, however, did not have significantly higher progression of other brain changes, as measured by MRI.
What are these white matter hyperintensities?
Dr. Deborah Friedman, professor of neurology and ophthalmology at the University of Texas South Western Medical Center in Dallas, explained in an editorial accompanying the research: "They're most likely ischemic changes related to migraines, but it's unlikely these itty bitty spots will grow or become a problem."
"Nerve cells get excited and fire more than usual, and then they fire less; it starts at the back of the brain and moves forward," Friedman said. "It could be ischemia. Not everyone with migraines gets them."
But Friedman is optimistic. "I wanted to headline the editorial 'Don't Panic,'" she said. "The MRI is not the whole story. We need to treat people with migraines like anyone, looking at the whole picture."
Friedman said physicians should work with migraine sufferers to help them reduce the classic risk factors of cardiovascular disease: obesity, high blood pressure, smoking, high cholesterol and lack of exercise.
It's possible, Friedman said, that some migraine sufferers may be at increased genetic risk for white matter disease, including stroke, transient ischemic attacks and cognitive changes.
"But there's no evidence that preventing migraines will decrease the risk of cardiovascular disease," she said.
To learn more about migraines, visit the U.S. National Institute of Neurological Disorders and Stroke.