New research infers that migraine increases the risk of cardiovascular events later in life.
Women are affected three or four times more often than men, though the reasons for this split are not understood.
Along with the headache, some migraine sufferers also experience a so-called aura that occurs just before or during an attack. This aura consists of a selection of symptoms that can include seeing flashing lights, experiencing blind spots, confusion, and a loss of balance.
Previous research has shown that migraine, especially when it occurs with an aura, is associated with an increased risk of stroke.
Although migraine is known to have a vascular component, it is not understood exactly why there is a link between migraine and stroke, but some scientists have theorized that there may also be a link between migraine and other cardiovascular events.
However, because migraines tend to peak during midlife, and cardiovascular events become more likely with advancing age, connections have been difficult to demonstrate.
Cardiovascular events and migraine
Breaking research, published in The BMJ, set out to investigate these potential links with cardiovascular events. A collaboration between scientists in Germany and the United States analyzed data from 115,541 women enrolled in the Nurses' Health Study II.
At the start of the study, the women were all free from angina and other cardiovascular illnesses. Aged 25-42, the participants' health was charted from 1989-2011.
Of the cohort, 17,531 individuals reported migraines at the start of the study. During the course of the follow-up, 1,329 experienced cardiovascular events and 223 died from cardiovascular disease.
Even after adjusting for confounding variables, the women with migraine had an increased risk of cardiovascular events, including heart attacks, angina/coronary revascularization procedures, and stroke.
The authors conclude:
"These results further add to the evidence that migraine should be considered an important risk marker for cardiovascular disease, at least in women."
Overall, the risk for cardiovascular events and stroke was 50 percent higher in women who had migraine, compared with those who did not. This effect was independent of age.
The research team, headed up by Prof. Tobias Kurth, also discovered that migraine was associated with a higher risk of cardiovascular mortality. Even once factors such as smoking, age, postmenopausal hormone therapy, hypertension, and oral contraceptive use were adjusted for, the effect was still present.
The size of cardiovascular concern
Although the study shows a clear association between migraine and cardiovascular events, caution should be used when interpreting the size of the interaction and its implications for individuals.
The research is published alongside an editorial written by Rebecca Burch, from Harvard Medical School, MA, and Melissa Rayhill, from The State University of New York at Buffalo. They say:
"The magnitude of the risk should not be over-emphasized [as] it is small at the level of the individual patient, but still important at a population level because migraine is so prevalent."
There are some limitations to the study - for instance, the team only used data from women, although they presume the effect would remain for men. Additionally, information for vascular biomarkers and migraine-specific information, such as the presence of aura, were not available to the team.
Although the results should not be cause for alarm, the authors of the editorial agree that "it's time to add migraine to the list of early-life medical conditions that are markers for later-life cardiovascular risk."
Further studies are likely to investigate the effect in men, and whether migraine severity and the presence of aura makes any difference to the level of cardiovascular risk.
It will also be important to understand how migraine might interact with other risk factors, such as smoking and obesity. On the other side of the coin, it will be interesting to examine whether drugs that treat the symptoms of migraine might also reduce the risk of cardiovascular events later in life.