New Harvard research confirms some links, rejects others.

Two new studies from Harvard examine the possible associations between migraine headaches and other conditions. One study offers encouraging news: the headaches will not hurt thinking skills. Another study suggests a warning: the headaches, when accompanied by aura, may signal an increased risk of heart attacks and stroke. "After high blood pressure, migraine with aura was the second strongest single contributor to the risk of heart attacks and strokes," says study author Dr. Tobias Kurth, adjunct associate professor of epidemiology at the Harvard School of Public Health. "It was followed by diabetes, family history, smoking, and obesity."

Migraines and dementia

A migraine is a throbbing headache that begins mainly on one side of the head, often accompanied by nausea. It can last from four to 72 hours, and it can be made worse by loud noise and bright light. Sometimes people who get migraines see pulsating lights or black spots or have blurry, distorted vision shortly before the headache kicks in. That's called migraine with aura.

While we don't completely understand what causes migraines, we do know that they are associated with an increase in tiny or "silent" brain lesions, which can be a risk factor for dementia and cognitive decline. "This led us to question if migraine headache is a progressive brain disease," says Dr. Pamela Rist, lead author of one study and a research fellow at the Harvard School of Public Health. But after analyzing data on more than 6,300 women, Dr. Rist and her team determined that migraines, with or without aura, do not appear to lead to cognitive decline. They published their research recently in BMJ. "It is reassuring news for people with migraines," says Dr. Rist.

Migraines and vascular disease

The other Harvard study, presented at the American Academy of Neurology meeting in March, focused on more than 27,000 women, of whom 1,400 had migraine with aura (MA). Researchers found that MA was a strong contributor to the risk of developing major cardiovascular events such as heart attack or stroke.

While the study does not prove that MA is causing vascular events, Dr. Kurth says MA is a warning sign. "It should be considered a factor that could indicate increased risk of cardiovascular disease." There is currently no evidence that treating or preventing migraine reduces future risks of heart attack and stroke.

What you can do

Just because you have MA, it doesn't mean you'll have a heart attack or stroke. If you're concerned about your risk, you can reduce it the same way everyone can: by controlling blood pressure, quitting smoking, exercising, and maintaining a healthy weight.

If you do have migraines and cardiovascular disease, be sure to talk to your doctor about which drugs you can use to stop migraine attacks. Dr. Kurth says some drugs used to treat migraine can cause blood vessels to contract, which may restrict blood flow and cause complications for people with existing heart disease or a high risk of stroke. The drugs include triptans, such as sumatriptan (Imitrex), almotriptan (Axert), and frovatriptan (Frova), as well as ergotamines, such as dihydroergotamine (DHE-45) and ergotamine tartrate plus caffeine (Cafergot).