A recent systematic review and meta-analysis performed by Harvard Medical School researchers reports that people suffering from migraine with aura (MA) have a two-fold increased risk for ischemic stroke. Furthermore, the study suggests a magnified risk among migraineurs who are <45 years of age, smokers, and among women using oral contraceptives. The study results are published in the recent online issue of the British Medical Journal.
Markus Schürks, Instructor at the Division of Preventive Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, and colleagues, studied the link between migraine and cardiovascular diseases (CVD), by evaluating the risk for myocardial infarction, stroke, and death due to CVD among migraineurs. The researchers reviewed diverse cohort and case-control studies selected from Embase, PubMed, and Cochrane Library, including reference lists of reviews and studies published up to January 2009. After extracting the data, pooled relative risks and 95% confidence intervals were calculated. The following results were presented based on the data analyzed:
• Nine studies examined the connection between any migraine and ischemic stroke (RR=1.73; CI=1.31-2.29). It was indicated that stroke risk was considerably higher in people with MA (RR=2.16; CI=1.53-3.03) compared to those without aura (RR=1.23; CI=0.90-1.69). The study also suggested that this risk was higher in women (RR=2.08; CI=1.13-3.84) than in men (RR=1.37; CI=0.89-2.11). Age below 45, smoking, and use of estrogen-based contraceptives added to the risk.
• Eight studies examined the association between migraine and myocardial infarction (RR=1.12; CI=0.95-1.32); and five studies assessed the link between migraine and death from cardiovascular disease (RR=1.03; CI=0.79-1.34). No overall association was observed between any migraine and the CVD assessed, other than stroke.
• One study, which examined the link between women migraineurs and aura, and myocardial infarction and death due to CVD, indicated a two-fold increased risk.
In an earlier study, the Harvard Medical School researchers (Neurology, 2008) explored the correlation between migraine aura, CVD risk, and methylenetetrahydrofolate reductase gene (MTHFR) 677C>T polymorphism. The study suggested a moderate protective effect conferred by the TT genotype of the MTHFR gene on MA. The study further demonstrated a substantial increase in the stroke risk among migraineurs with aura, carrying TT mutation, a major determinant of plasma total homocysteine levels. The elevated stroke risk in this case is mainly attributable to high homocysteine and low plasma folate concentrations.
Earlier, MacClellan et al (Stroke, 2007) assessed the probable relation between migraine with and without visual aura, and ischemic stroke in a cohort of 386 female subjects (15 to 49 years of age) with a history of first ischemic stroke and 614 controls of the same age and ethnicity. The population-based case-control study demonstrated 1.5 times increased risk of ischemic stroke in women migraineurs with visual aura, particularly among those without stroke-associated medical conditions, compared to controls. The study also concluded that factors, particularly smoking and use of oral contraceptives, significantly increase the risk of probable migraine with visual aura (PMVA), and recent onset of PMVA.
According to the 2007 American Migraine Prevalence and Prevention (AMPP) study conducted by the National Headache Foundation, approximately 12% of the American population was affected by migraine headaches. The National Headache Foundation estimated a loss of 157 million workdays every year due to pain and associated migraine symptoms in the US. Migraine headaches with aura are associated with many warning symptoms, such as visual distortions in the form of flashing lights, ringing in the ears, aphasia, slurred speech, and vomiting prior to the actual incidence of migraine attack.
In view of the current findings, young women migraineurs with aura should be warned about the increased risk for ischemic stroke associated with the use of estrogen-based contraceptives and/or smoking. Considering migraine to be one of the most debilitating physical conditions, more awareness should be created among migraineurs regarding the lifestyle options, nutritional supplementations, and recent pharmacological advances.
References
1. Schürks M, Rist PM, Bigal ME, Buring JE, Lipton RB, Kurth T. Migraine and cardiovascular disease: systematic review and meta-analysis. BMJ. 2009 Oct 27;339:b3914.
2. Schürks M, Zee RY, Buring JE, Kurth T. Interrelationships among the MTHFR 677C>T polymorphism, migraine, and cardiovascular disease. Neurology. 2008 Aug 12;71(7):505-13.
3. Meleady R, Ueland PM, Blom H, et al. Thermolabile methylenetetrahydrofolate reductase, homocysteine, and cardiovascular disease risk: the European Concerted Action Project. Am J Clin Nutr. 2003 Jan;77(1):63-70.
4. MacClellan LR, Giles W, Cole J, et al. Probable Migraine With Visual Aura and Risk of Ischemic Stroke: The Stroke Prevention in Young Women Study. Stroke. 2007 Sep; 38(9):2438-45.
