Women who have migraines are more likely to accumulate brain lesions than those who don’t suffer from the debilitating headaches, according to a Dutch study that suggests more research is needed to determine what they mean.
While it’s not clear what causes the damage, seen in the connective fibers of the brain or white matter, the good news is that they don’t seem to result in long-term harm to the brain, researchers said in the study published today in the Journal of the American Medical Association.
In the nine-year study, magnetic resonance imaging showed that 77 percent of women with migraines had an increase in spots in their brain’s white matter, compared with 60 percent of women who didn’t have migraines. The findings also showed that the lesions don’t affect cognitive function and the number, frequency and severity of the headaches don’t affect the number of spots that appear over time.
“The data make it less plausible that migraine attacks cause the lesions,” said study author Mark Kruit, a neurologist in the Department of Radiology at Leiden University Medical Center in the Netherlands, in a Nov. 12 e-mail. “The importance of the lesions is probably low because we did not find a clear effect on cognitive abilities. People should not be scared that migraine attacks cause brain changes.”
About 15 percent of the general population suffers from migraines, the authors wrote. The results also suggest preventing the headaches probably won’t result in fewer lesions because there was no association between the number of migraines a woman had and an increase in spots over time, Kruit said.
“Preventive migraine therapy should therefore not be started based on our results,” he said.
The lesions are only visible on MRI scans, he said. They may have many different causes and probably can’t be healed.
Researchers in the study looked at whether men and women with migraines have an increased incidence of spots or brain lesions nine years after having an initial MRI, whether the headache frequency increased the number of lesions and whether the damage was associated with a decline in memory and thinking. The research was a follow-up to a 2000 study.
The study found that 112 out of the 145 women in the migraine group and 33 of the 55 women in the control group had an increase in the number of spots on the brain nine years after they received their first MRI. There was no similar association in men.
The lesions weren’t associated with changes in thinking or memory, they found. Based on the results, Deborah Friedman, who wrote an accompanying editorial, said migraine sufferers shouldn’t panic.
“These little lesions do show up on the MRI scans not infrequently,” said Friedman, a professor of neurology, neurotherapeutics and ophthalmology at the University of Texas Southwestern Medical Center in Dallas, in a Nov. 11 telephone interview. “Based on this study, we don’t think they’re anything to worry about.”
More studies though are needed to look at the possible relationship between the lesions in female migraine sufferers and stroke, Kruit said. Previous research has shown a higher risk of stroke and heart attack for middle-aged women who have migraine headaches preceded by visual warning symptoms called auras. A September 2008 study in the journal Neurology by researchers in Austria and Italy found that the headache sufferers may have a higher risk of developing deadly blood clots.
Friedman said doctors should treat risk factors for stroke like smoking, high blood pressure, obesity and lack of exercise as a preventive measure. Those factors are more likely to contribute to a heart attack or stroke than migraine, she said.