Study confirms link between migraines and stroke

People who suffer migraines are about twice as likely as people without the headaches to suffer a stroke caused by a blood clot a new research review finds. The current analysis combined the results of 21 published studies. The meta-analysis confirms a connection between migraines and ischemic stroke -- the most common form of stroke, occurring when a clot disrupts blood flow to the brain. Across the studies, migraine sufferers were about twice as likely to suffer an ischemic stroke as people without migraines. Experts are not sure why the relationship exists, and it is not yet known whether the migraines themselves directly lead to strokes in some people.

It's likely, however, that a common underlying process contributes to both migraines and stroke risk, said Dr. Saman Nazarian, the senior researcher on the new study and an assistant professor at Johns Hopkins University School of Medicine in Baltimore.

For now Dr Nazarian advises according to an email to Reuters Health; the bottom line for migraine sufferers is that they should be particularly vigilant about controlling any modifiable risk factors for stroke that they may have. Some of those risk factors include high blood pressure, smoking and diabetes.

The current findings are based on 21 international studies conducted between 1975 and 2007 and involving more than 622,000 adults with and without migraines.

Most of the studies took into account a number of factors that might help explain any connection between migraine and stroke risk -- such as age, high blood pressure, diabetes, smoking habits and weight.

The precise cause of migraines is not fully understood, but the pain involves constriction, and then swelling, of brain blood vessels related to a trigeminal nerve and inflammation in that nerve. One theory is that people with migraine may have dysfunction in the blood vessels throughout the body, which may explain the increased risk of stroke and, as some previous studies have found, heart attack. No one yet knows whether treating and preventing migraine attacks can do anything to affect people's risk of cardiovascular problems. The study is published in the American Journal of Medicine, online ahead of print May 20, 2010.