Suffering from migraines could be a portent of serious heart problems, a major new study suggest. Using the Danish National Patient Registry, researchers identified 51,032 people with migraines—71 percent of them women—and 510,320 people who were migraine free. The participants were, on average, 35 years old at the start of the study, and so their overall risk of developing cardiovascular disease was small. But during the 19-year study, researchers found that people with migraines were 49 percent more likely to have a heart attack, 59 percent more likely to develop a blood clot in their veins, and 25 percent more likely to have an irregular heartbeat. They had nearly double the risk of stroke. The risks were all higher in the first year following a migraine diagnosis. “We now have accumulating evidence that migraine is a risk factor for cardiovascular disease,” study lead author Kasper Adelborg told The New York Times. There are several reasons migraines might be linked with heart problems. It could be that migraines are triggered by the sudden constriction of blood vessels, reducing blood flow to the brain and raising the risk for stroke. Anti-inflammatory drugs that are used to treat migraine pain could also increase the risk of cardiovascular disease.