You know that high blood pressure, diabetes and obesity increase your risk for cardiovascular disease—but you may not know that your heart risk also rises if you suffer from migraine with aura (aura means visual or other sensory disturbances that precede the headache). Yet that’s the startling news from a new study.

The researchers analyzed data on nearly 28,000 women age 45 and older. The participants, none of whom had cardiovascular disease at the start of the study, answered various questions about their health, including whether they had a history of migraine with aura. The participants were then followed for 15 years, with researchers scouring medical records to see who ended up having or dying from a cardiovascular “event” (heart attack or stroke).

Troubling finding: After analyzing the data, the researchers found that migraine with aura was the second biggest individual risk factor for cardiovascular disease, with an incidence of 7.9 events per 1,000 women. The only risk factor that surpassed it was having very high blood pressure (180 or higher for the top number of a blood pressure reading), with an incidence of 9.8 events per 1,000 women.

To put these numbers into perspective, consider that the incidence associated with diabetes was 7.1 cardiovascular events per 1,000 women…for smoking, it was 5.4 events per 1,000 women…for severe obesity (a body mass index of 35 or higher), it was 5.3 events per 1,000 women.

This study does not prove that migraine with aura causes cardiovascular disease, only that the two are associated. And questions remain, of course. For instance, since the new study included only women, we don’t know whether men who experience migraines with aura are similarly at risk. Also, it is not known whether controlling migraines with medication would reduce heart risk…or whether migraine medications themselves (such as those that work by constricting the blood vessels) might contribute to heart risk—though the researchers said that this was unlikely, given that patients who experience migraine without aura also take these drugs yet the study found no link between cardiovascular disease risk and migraine without aura.

Still, until more information is available, women and men who have a history of migraines with aura would be wise to mention this study to their doctors and ask for a careful assessment of their individual risk factors for cardiovascular disease—including physical condition, lifestyle and family history—and then follow up if changes are needed to lower their risk.