Women who have migraine with aura in their middle years are more likely than others to show cerebellar “infarct-like lesions” on brain MRI in late life, according to a report in JAMA.
This link between migraine with aura and presumed occult stroke is independent of cardiovascular risk factors and CV disease history at either time period, said Ann I. Scher, Ph.D., of the Uniformed Services University, Bethesda, Md., and her associates.
These findings from a prospective longitudinal study are consistent with those of the recent cross-sectional CAMERA (Cerebral Abnormalities in Migraine, an Epidemiological Risk Analysis) study (JAMA 2004;291:427-34), “the only other study that measured infarcts on MRI, which also found the migraine-associated infarcts to be preferentially located in the cerebellum,” the investigators noted.
As such, they confirm the previous findings and point to the need for additional research with sequential MRIs “to better establish the temporality and dose-response relationship between migraine with aura and brain infarcts,” they added.
Several researchers cautioned, however, that without knowledge of the source or type of lesions that were seen and without any known clinical symptoms or consequences of the lesions, it is too early to say whether migraine has harmful effects on the brain.
Dr. Scher and her colleagues studied this issue using data from the Reykjavik Study, a population-based prospective assessment of cardiovascular disease in Iceland, which began in 1967. They examined data on a subset of 4,689 subjects who were middle-aged (average age, 51 years) at enrollment, when migraine data were collected, and were elderly (average age, 76 years) in 2002-2006 when brain MRI was performed.
There were 2,693 women and 1,996 men in this study. A total of 12% (6% of the men and 17% of the women) had migraine at midlife, including approximately 5% who had migraine without aura and approximately 8% who had migraine with aura.
“Infarct-like lesions” were significantly more prevalent in women who reported migraine with aura in midlife (31%) than in women who did not have migraine (25%), but no difference was found in prevalence among men.
Similarly, infarcts in the cerebellum, but not in cortical or subcortical locations, were more prevalent in women who reported migraine with aura in midlife (23%) than in women without headache (15%), but there was no difference in prevalence among men.
“However, we cannot rule out a possible increased risk for men [who have] migraine with aura, due to the relatively small number of [such] men in our sample,” the investigators noted (JAMA 2009;301:2563-70).
In an editorial comment accompanying this report, Dr. Tobias Kurth and Dr. Christophe Tzourio of the University Pierre et Marie Curie, Paris, said these findings should be interpreted with caution (JAMA 2009;301:2594-5).
“In the absence of the source and the nature of 'infarct-like lesions' and the absence of clinical symptoms or consequences, it is premature to conclude that migraine has hazardous effects on the brain,” they said.
“New studies examining the association of migraine with structural brain changes and brain function should improve understanding of the associations, and perhaps further unveil migraine-specific mechanisms,” Dr. Kurth and Dr. Tzourio said.
Dr. Scher has served on advisory boards of Endo Pharmaceuticals and OrthoMcNeil Neurologics.
Dr. Kurth reported receiving funding from McNeil Consumer & Specialty Pharmaceuticals, Merck, and Wyeth Consumer Healthcare; serving as a consultant to i3 Drug Safety and World Health Information Science Consultants; and receiving honoraria from Genzyme, Merck, and Pfizer.
Dr. Tzourio reported receiving fees from Sanofi-Synthelabo and Merck Sharpe & Dohme.
The study was funded by the National Institutes of Health and several individual NIH institutes, as well as Hjartavernd (the Icelandic Heart Association), the Althingi (the Icelandic Parliament), and the Migraine Research Foundation.