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Researchers who study migraine have not yet determined what causes this debilitating neurological disease. Some scientists theorize that changes to the brainstem – the lowest part of the brain, just above the spinal cord – may lead to the development of migraine. Some studies indicate that people with migraine tend to have abnormal levels of the chemicals (neurotransmitters) that transfer electrical impulses between cells.
Another theory of migraine development relates to the cardiovascular system – the heart and blood vessels. People born with certain congenital heart defects seem more likely to develop migraine. Studies also show a relationship between migraine and increased risk for stroke. Research into the relationship between cardiovascular disease and migraine continues.
Risk factors for migraine
It is important to note that while science is good at finding correlations, or apparent relationships, between factors and disease, correlation does not prove that the risk factor causes the disease. Many risk factors for migraine have been identified and are being studied, but none have been pinpointed as the cause of migraine.
Age is a risk factor in migraine. Migraines begin before age 40 in more than 90 percent of people.
Genetic risk factors
Migraine is not passed down in a clear pattern between parent and child. However, if you have a relative with migraine, you may be about three times more likely to have migraine than someone with no family history of migraine. Research indicates that inherited factors may account for as much as 40 to 50 percent of the risk for migraine. For this reason, most researchers agree that genetic and environmental factors both contribute to the development of migraine.
Women are three times more likely to develop migraine than men. Women are also more likely to develop chronic migraine – experiencing migraine symptoms at least 15 days in each month – than men. About 85 percent of those with chronic migraine are women. More than half of women with migraine experience spikes in migraine symptoms at certain points in their menstrual cycle when hormones fluctuate. Menstrual migraines may begin during adolescence, peak in the 30s, and taper off after menopause.
Environmental risk factors
Most researchers do not believe that genetics alone determine who gets migraine. However, research has not yet identified which environmental factors play a role in determining who develops migraine and who does not.
Scientists have identified several risk factors associated with progress to chronic daily migraine, the most severe and disabling form of the disease. Risk factors that seem to make people more likely to develop chronic daily migraine include:
Studies focused on preventing the progression to chronic daily migraine are ongoing.