According to Teshamae Monteith, a doctor and one of the authors from the University of Miami, Miller School of Medicine, "One possible mechanism of increased stroke risk may be oxidative stress, which has been theorized to have a role in migraine and may lead to increased susceptibility to vascular events among active smokers."
While migraines themselves did not signal a greater risk of stroke, smokers who also had migraines were three times as likely to have a stroke, said the researchers in the Northern Manhattan Study. The 1,292 participants, who were an average of 68 years old, were monitored for 11 years. The scientific team, from University of Miami and Columbia University, believes that the effects of migraine and smoking may compound one another, leading to ischemic events. As they wrote, "Taken together, we suspect that a synergic action may occur between vascular changes of migraine and smoking as an effect modifier, although further work is necessary to elucidate this association."
Statistically, the researchers did not discount the possibility that the findings were a matter of chance, but they believe that the migraines have been linked to stroke risks in previous studies, especially in young women. Monteith concluded, in a statement from the American Academy of Neurology, which publishes the journal, "While this investigation of migraine and vascular events in older people found that only smokers with migraine have an increased risk of stroke, earlier studies have shown that women younger than 45 who have migraine with aura are also at an increased risk of stroke, whether or not they smoke."
In 2010 researchers determined that people who suffer migraines are about twice as likely as people without the painful headaches to suffer a stroke caused by a blood clot. As reported in Reuters, the research combined the results of 21 previous studies and confirmed a connection between migraines and ischemic stroke -- the most common form of stroke, occurring when a clot disrupts blood flow to the brain, according to findings published in the American Journal of Medicine. Dr. Saman Nazarian, the senior researcher on the new study and an assistant professor at Johns Hopkins University School of Medicine in Baltimore, said it was likely that a common underlying process contributes to both migraines and stroke risk and advised migraine sufferers to control risk factors such as high blood pressure, smoking and diabetes (http://www.reuters.com/article/2010/06/02/us-migraines-stroke-idUSTRE6513MN20100602).