Women who suffer frequent migraines may have an even bigger headache to worry about: A new study finds that women whose migraines include visual disturbances, known as auras, are at increased risk for developing cardiovascular disease.

Migraines affect an estimated twenty-eight-million Americans each year. The debilitating headaches are often triggered by stress, bright lights, strong scents or even changes in the weather.

Many migraine sufferers complain of sensitivity to light and sound. But one in five experience more serious visual symptoms, ranging from temporary loss of sight to colorful hallucinations involving flickering stars, glimmering shapes or streaking lines.

For years, physicians have noted that women who endure these visual disturbances, called auras, seem to suffer from more strokes and heart attacks than other women. Researchers at Harvard University say that’s no coincidence. They conducted a ten-year study and found that women who experience migraine-related auras are more than twice as likely as other women to die from cardiovascular disease.

Doctors aren’t sure why these women are at greater risk for developing disease. But researchers have noticed that a surprising number of women who experience auras are smokers or have other risk factors for heart disease, such as high cholesterol, elevated blood pressure or a family history.

Chronic migraines without the visual disturbances aren’t associated with cardiovascular disease. But by maintaining a healthy lifestyle and visiting your doctor regularly, you can ensure that you do your best to maintain a healthy heart.