Research: Migraine increases stroke risk
Migraine with aura (temporary visual or sensory disturbances before or during a migraine headache) is associated with a twofold increased risk of stroke, finds a study published in the British Medical Journal today. Further risk factors for stroke among patients with migraine are being a woman, being young, being a smoker, and using oestrogen containing contraceptives.
The risk was highest among young women with migraine with aura who smoke and use oestrogen containing contraceptives.
Migraine is a common, chronic disorder that affects up to 20% of the population. Women are affected up to four times more often than men. Up to one third of sufferers also experience an aura prior to or during a migraine headache (often described as the perception of a strange light, an unpleasant smell or confusing thoughts or experiences).
Doctors have long suspected a connection between migraine and vascular events such as stroke. So to investigate this further, an international team of researchers analysed the results of nine studies on the association between any migraine (with and without aura) and cardiovascular disease. Differences in study design and quality were taken into account to minimise bias.
They show that migraine with aura is associated with a twofold increased risk of ischemic stroke. This risk is further increased by being female, age less than 45 years, smoking, and oestrogen containing contraceptive use.
There was no association between migraine and heart attack or death due to cardiovascular disease.
In light of these findings, the authors recommend that young women who have migraine with aura should be strongly advised to stop smoking, and methods of birth control other than oestrogen containing contraceptives should be considered. They also call for additional research to investigate the association between migraine and cardiovascular disease in more detail.
The absolute risk of stroke for most migraine patients is low, so a doubling of risk is not cause for panic, explains Elizabeth Loder from Brigham and Women's Hospital, Boston, in an accompanying editorial. However, at a population level, this risk deserves attention because the prevalence of migraine is so high.