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.

For the video version of this post, click here.

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.

Soul food is bad for the heart

For the video version of this post, click here. What diet do you ascribe to?  If you answered “I have no idea what you mean”, then you can join the rest of the 80% of Americans who don’t follow a specified diet regime. Sure, lots of us try to avoid fat, or sugar, or meat, but when it comes to defining the health benefits of a particular dietary pattern, it’s hard to label people.

Now an article appearing in Circulation from researchers at the University of Alabama at Birmingham suggests that a “Southern” style diet may significantly increase the risk of heart disease.

Before we get our pitchforks and charge over to Paula Deen’s house, let’s take a minute to look how this study was done. The data comes from the “REGARDS” study, which was a large cohort study primarily designed to look at stroke risk factors.  About half of the REGARDS cohort, 15,000 people, were eligible for this analysis and provided dietary data in the form of a food frequency questionnaire.

What’s cool about this study is that they derived the dietary patterns without any preconceived notions.  Using a technique called factor analysis, they let the data speak for itself, and find which foods tend to “hang together” in the diets of individuals.  Five major patterns emerged:  the Southern diet (which is the focus of the study) was characterized by fried foods, eggs, organ meats, and sugar-sweetened beverages. Other dietary patterns included a “plant-based” pattern, a “convenience” food pattern, a “sweets” pattern and, my favorite, an “alcohol and salad" pattern.

What I like about this study is that it doesn’t force individuals into a specific category.  The analysis allows your dietary pattern to be part Southern, part plant-based, for example. So we’re not in the situation of trying to label each person with one, and only one, diet.

After follow-up of around 6 years, greater “adherence” to the Southern diet increased the risk of incident coronary heart disease by around 35%. To stop one heart attack per year, you’d need to convert roughly 1200 fried-organ meat gourmands to a healthier option, but that assumes there were no confounders at play.  Clearly there were, as the southern dietary pattern was associated with male sex, black race, lower income, and diabetes.  The authors adjusted for these factors, but it’s likely that other socio-economic factors including access to health care may play a significant role here.

In unfortunate news, the “Alcohol and Salads” dietary pattern, which describes my eating habits pretty darn well, had no relationship to heart disease in either direction.  This may hurt sales of my upcoming diet book “Alcohol and Salads: 20 blurry days to a better you”.

The analysis doesn’t allow for too much subtlety - describing anyone’s dietary habits using 5 criteria is limiting.  In addition, the lack of signal in the “sweets” dietary pattern runs counter to a lot of prior research linking high processed carbohydrate consumption to heart disease. That said, I for one, am going to forgo that second helping of chicken-fried steak tonight.