Women who suffer from migraine headaches in middle age accompanied by neurological aura (visual disturbances, dizziness or numbness that can precede migraines) are more likely to have damage to brain tissue in the cerebellum later in life, according to a study by researchers at the National Institute on Aging (NIA) of the National Institutes of Health, the Uniformed Services University of the Health Sciences and the Icelandic Heart Association in Reykjavik. Researchers noted that many people have these types of 'silent' brain lesions, but their effect on physical and cognitive function in older people is not well studied.

The study appears in the June 24, 2009, issue of the Journal of the American Medical Association. The researchers found that women are more susceptible than men to localized brain tissue damage identified on magnetic resonance images (MRI) and that women who reported having migraines with aura were almost twice as likely to have such damage in the cerebellum as women who reported not having headaches.

Researchers noted that while the study shows an association in women between migraine and cerebellar tissue damage later in life, the functional significance of such brain changes remains an open question. The cerebellum is located in the lower back side of the brain and is involved in functions such as motor activity, balance and cognition.

"This long-term population-based study increases interest in determining whether migraine could be a risk factor for brain lesions with clinical consequences over time," said NIA director Richard J Hodes. "Further research should help us better understand what these changes may mean for individuals and for brain function with age."

Migraine headaches affect approximately 11 per cent of adults and five per cent of children worldwide and are more common in women than in men. Migraines are often accompanied by extreme sensitivity to light and sound, nausea and vomiting. Some individuals with migraine also experience neurological aura symptoms, including temporary visual disturbances that can appear as flashing lights, zig-zag lines or loss of vision.

This study examined migraine headaches in a community-dwelling cohort of older people. Between 1972 and 1986, when participants were middle-aged (average age 50.9), they were asked about type and frequency of headaches. MRI scans of the cortex and cerebellum brain regions were conducted on 4,600 study participants between 2002 and 2006, when participants' average age was 76.2.

Participants were divided into four groups: migraine headache with aura once or more per month, migraine headache without aura, nonmigraine headache and no headache. The researchers found that overall, 17 per cent of the women were classified as having migraine headaches, including 10.3 per cent with migraine with aura. Only 5.7 per cent of men were classified as having migraine.

Overall, MRI scans revealed the presence of any brain lesion in 39.3 per cent of the men and 24.6 per cent of the women. Prevalence of cerebellar lesions in women with migraine with aura was 23.0 per cent vs. 14.5 percent for women not reporting headaches. There was no statistically significant difference in prevalence of these lesions in men (19.3 vs. 21.3 per cent).

"After adjusting for risk factors for cardiovascular disease, transient ischemic attack or stroke in middle age or late life, we found that women who suffered from migraines with aura in middle age had an almost twofold increased risk of brain lesions in the cerebellum later in life," said Lenore Launer, senior author and chief of the neuroepidemiology section of the Laboratory of Epidemiology, Demography, and Biometry in the NIA's Intramural Research Programme. "We are currently investigating the clinical implications of these brain lesions in this group of individuals. We are also interested in whether this association represents a cause and effect relationship or whether some other factors are responsible for the apparent association. The findings from this study are consistent with those from a previous study conducted in younger people using a similar protocol."

Participants were part of the Reykjavik Study and the Age Gene/Environment Susceptibility-Reykjavik Study (AGES-RS). Originally established to study heart disease in Iceland, the Reykjavik Study includes a random sample of men and women born between 1907 and 1935 and living in Reykjavik at the beginning of the study in 1967. In 2002, AGES-RS continued the Reykjavik Study to examine risk factors, genetic susceptibility and gene-environment interactions in relation to disease and disability in later life.

This study was funded by the National Institute on Aging, the Icelandic Heart Association and the Icelandic Parliament. Components of the study were also supported by the National Eye Institute, the National Institute on Deafness and Other Communication Disorders, the National Heart Lung and Blood Institute and the Migraine Research Foundation.

The NIA leads the federal effort supporting and conducting research on aging and the medical, social and behavioral issues of older people.