A gene variant previously thought to increase the risk of migraine in women has been shown, in fact, to have a mildly protective effect, according to a new study published in the journal Neurology. However, the study also shows that if women go on to develop migraines despite carrying the prophylactic MTHFR 667TT variant, they appear to have an increased risk of heart disease and stroke.
Dr Tobias Kurth, assistant professor of medicine at Harvard Medical School and an associate epidemiologist at Brigham and Women's Hospital in Boston, led the research team which studied 4507 women with a history of migraine, focusing particularly on those reporting migraine with aura - where patients sense strange lights and unpleasant smells - in conjunction with a control group of women with no history of migraine. Cardiovascular events, such as stroke or heart attack, were then monitored for the next 12 years.
The MTHFR gene has long been suspected of playing a role in the pathology of both migraines and cardiovascular disease - as well as a number of other disorders - but establishing a firm link has proved elusive, with much contradictory data being published. MTHFR is thought to modulate levels of a highly reactive amino acid species called homocysteine, which if produced in excess is known to break down and inhibit the normal cellular function of some proteins.
Researchers in the most recent study screened women to see what version of the MTHFR gene they carried: 11 per cent of the study population carried the protective variant. In isolation, the variant gene conferred no increased risk of cardiovascular disease and was slightly preventative against migraine with aura; however, women who went on to develop migraine with aura despite carrying the variant gene were three times more likely to develop cardiovascular disease.
'At the moment, we're not suggesting genotyping for women with migraines with aura. The consequences are completely unclear right now', said Kurth. However, as both cigarettes and birth control pills can increase the risk of vascular problems, women who have migraine with aura and also smoke should understand their increased risk and might want to discuss birth control options with their doctors, Kurth added.
'The take-home message here is that if you have migraine with aura, you're likely have an increased stroke risk and you may want to be more careful', said Dr Keith Siller, medical director of the Comprehensive Stroke Care Center at New York University's Langone Medical Center.