New Cohort Study Links Migraine and Cardiovascular Disease
The long-term effects of migraine have been an object of interest for researchers in the past several decades. While not everything about migraine is understood, researchers have discovered a nearly two-fold increased risk in both hemorrhagic and ischemic subtypes of stroke in the migraine population. It is often hypothesized that this risk is isolated more to the population of migraineurs who experience migraine with aura, however, research is still underway to further characterize this relationship and understand exactly why the two are connected.
A newer, and less understood aspect of migraine research is its connection to other cardiovascular diseases. Several previous studies have linked migraine to myocardial infarction, blood clotting, and other cardiovascular complications. However, these studies are not often very definitive, as both migraine and cardiovascular complications are most prominent during midlife or later. This makes proving that one truly causes the other particularly challenging.
The recent findings:
A new, long-term study, led by Professor Tobias Kurth, investigates the link between migraine and cardiovascular disease. The article, published on The BMJ, includes data from 115,541 female participants in an ongoing cohort study (the Nurses’ Health Study II), who were 25-42 years old at the beginning of data collection. None of the women suffered from angina or other cardiovascular diseases when the study began in 1989, and their health was charted through 2011. Of the original sample population, 17,531 reported that they had been diagnosed with migraine. Upon follow up, 1,329 participants had experienced major cardiovascular disease events, such as heart attacks and angina/coronary revascularization, and 223 died due to cardiovascular disease.
The researchers concluded that there was in fact an association between migraine and cardiovascular disease. They also noted that this association was not affected by potential confounding variables, such as age, oral contraceptive use, current smoking status, hypertension, and postmenopausal hormone use. Overall, the risk for cardiovascular disease and stroke was determined to be 50% higher for women who had migraine as opposed to without.
What to do with this information:
Although the study does imply a clear association between migraine and cardiovascular disease, and concludes that migraine should be considered a risk factor for cardiovascular disease, it doesn’t mean every individual with migraine need be on high alert for future complications. The data analyzed has its own drawbacks. These include, using data centered solely around women, and a lack of migraine-specific information (for example, the presence or absence of aura, etc.), as well as missing information on vascular biomarkers.
An editorial published along with the article, sums up where to go from here quite nicely, stating, “The magnitude of the risk should not be over-emphasized, however. It is small at the level of the individual patient but still important at a population level because migraine is so prevalent.” Essentially, although there may be a link between migraine and cardiovascular disease, it is best observed at large. We know these trends and associations exist, because thousands of individuals have been monitored, which has tipped the scale towards discovery. At the individual level however, the probability of association is quite small, and may even be non-existent.
We as a community, both science-based and experience-based, have a long way to go in the process of determining the longer-term effects of migraine. But for now, individuals with migraine can use the knowledge we currently have, and if possible, work towards reducing other potential cardiovascular disease risk factors they may possess.1,2
- Migraine and risk of cardiovascular disease in women: prospective cohort study, Tobias Kurth et al., The BMJ, doi: 10.1136/bmj.i2610, published online 31 May 2016.
- Editorial: Migraine and vascular disease, Rebecca C Burch et al., The BMJ, doi: 10.1136/bmj.i2806, published online 31 May 2016.