Migraine: A New Cardiovascular Risk Factor?

I’m going to get personal here.  I had my first migraine - in my life - about three weeks ago. For those of you who have been longtime sufferers, I am truly sorry.  I was literally testing my own neck stiffness to make sure I didn’t have meningitis. But aside from the blistering pain knocking you out of commission for several hours (or several days), a new study appearing in the BMJ suggests there is something else migraine sufferers need to worry about – cardiovascular disease.

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Researchers used data from the Nurses Health Study 2, a large, questionnaire-based prospective cohort study that began back in 1989 and enrolled over 100,000 nurses. The idea here was that the nurses (all female by the way) would be more reliable when answering health-related questionnaires than the general public.

In 1989, 1993, and 1995 the questionnaire asked if the women had been diagnosed, by a physician, with migraine. That’s it. No information on treatment, severity, or the presence of aura – a factor that has been associated with cardiovascular disease in the past.

This response was linked to subsequent major cardiovascular events including heart attack, stroke, and coronary interventions.

The researchers found a higher rate of this outcome among those who had been diagnosed with migraine. In fact, even after adjusting for risk factors like age, cholesterol, diabetes, hypertension, smoking, and more, the risk was still elevated by about 50%. So those of us with migraines – is it time to freak out?

Not too much.  The overall rate of major cardiovascular events in this cohort was just over 1% - not exactly common. That means the absolute risk increase is 0.5%, which doesn’t sound quite as dramatic as the 50% relative risk increase.  Putting that another way, for every 200 patients in this cohort with migraine, there was one extra case of cardiovascular disease.  Not exactly a risk factor to write home about.

But, to be fair, cardiovascular disease gets more common as we age – had the study had even longer follow-up, we might have seen a higher event rate.

Other studies have found similar findings with migraine. The women’s health study, for instance, found a nearly two-fold increased risk in cardiovascular events, but only in those who had migraine with aura – a covariate missing from the current dataset.

Should women with migraine take precautions against cardiovascular disease? The jury is out. Since we don’t know the mechanism of the link, if any, we don’t know the best way to treat it.  But clearly any studies of migraine therapy would do well to keep an eye on cardiovascular endpoints.