Literature Review

Migraines linked to higher risk of dementia



Migraines are associated with a significantly greater risk of Alzheimer’s disease and all forms of dementia except vascular dementia, according to research published online Sept. 4 in the International Journal of Geriatric Psychiatry.

Dr. Suzanne Tyas, associate professor in the School of Public Health and Health Systems at the University of Waterloo in Ontario.

Dr. Suzanne Tyas

In the Manitoba Study of Health and Aging, a population-based, prospective cohort study, 679 community-dwelling adults with a mean age of 75.9 years were followed for 5 years. Participants screened as cognitively intact at baseline had complete data on migraine history and all covariates at baseline and were assessed for cognitive outcomes 5 years later.

The study showed that a history of migraines was associated with a 2.97-fold greater likelihood of dementia, after adjustment for age, education, and a history of stroke, compared with individuals without a history of migraine. Individuals with Alzheimer’s disease were more than four times more likely to have a history of migraines (odds ratio 4.22).

However, researchers found no significant association between vascular dementia and a history of migraines, either before or after adjusting for confounders but particularly after incorporating a history of stroke into the model.

Lead investigator Suzanne L. Tyas, PhD, associate professor in the School of Public Health and Health Systems at the University of Waterloo, Ont., and coauthors suggested that the association between migraine and dementia was largely driven by the strong association between migraines and Alzheimer’s disease.

“This interpretation is supported by the weaker association for dementia than for Alzheimer’s disease, reflecting a dilution of the association with migraines across all types of dementia including vascular dementia, where a significant association was not found,” the researchers wrote.

The study population was 61.9% female, and no men reporting a history of migraine were diagnosed with dementia. While the study reflected a strong association between migraine and dementia in women, the researchers said they were unable to assess potential gender differences in this association.

Commenting on possible mechanisms behind the association, the authors wrote that there were overlaps underlying the biological mechanisms of migraine and dementia. Vascular risk factors such as diabetes, hypertension, heart attack, and stroke are associated with the development of dementia, and a relationship of these risk factors and migraine also has been seen.

“Many of the mechanisms involved in migraine neurophysiology, such as inflammation and reduced cerebral blood flow, are also underlying causes of dementia,” they wrote. “Repeated activation of these pathways in chronic migraineurs has been shown to cause permanent neurological and vascular damage.”

They also observed that the association could be influenced by genetic factors, as individuals with presenilin-1 mutations, which predispose them to Alzheimer’s disease, are more likely to experience migraines or recurrent headaches.

They suggested their findings could inform preventive strategies and treatments for Alzheimer’s disease, as well as interventions such as earlier screening for cognitive decline in individuals who experience migraines.

The study was funded by Manitoba Health and the National Health Research and Development Program of Health Canada. No conflicts of interest were declared.

SOURCE: Morton R et al. Int J Geriatr Psychiatry, 2019 Sep 4. doi: 10.1002/gps.5180.

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