What is a migraine?
A migraine is an intense headache that may be accompanied by nausea, vomiting, fatigue, sensitivity to light and sound, and mild to severe throbbing pain, usually worse on one side of the head. Women are more likely than men to have migraines, especially between the ages of 20 and 44.1 There are an estimated 28 million migraine sufferers in the US, and 70% of them are women.2
The two most common types of migraine are defined by their warning symptoms:
- Migraine with aura: Known as the "classical" migraine, it affects about 20% of migraine sufferers.3 This type of migraine has warning symptoms, called auras, that usually affect vision—such as bright flashing lights or spots—and occur 10 to 30 minutes before the migraine. There are other types of auras that affect other senses, such as a ringing in the ear or changes in smell or taste. Migraines with aura may also include other symptoms such as difficulty speaking, weakness of an arm or leg, confusion, pain, nausea, and sensitivity to light.
- Migraine without aura:Known as the "common" migraine because it occurs in 80% of migraine sufferers in the US, this type of migraine has no visual warning symptoms. However, symptoms such as fatigue, depression, or anxiety may appear hours before the migraine.
Does having migraines increase my risk of stroke?
Women who have migraines with aura have twice the risk of blocked-vessel (ischemic) stroke and heart disease, and are more than twice as likely to die from cardiovascular disease.4-6 It is not clear if women who have migraines with aura have an increased risk of stroke because of the migraine alone, or if it is related to other risk factors that also contribute to stroke, such as high blood pressure and smoking. Migraines without aura do not seem to increase your risk of stroke.4
The longer you have migraines, the more the blood vessels in your brain are affected by the changes that occur during a migraine. One study of 300 women found that the risk of stroke increased in those who had migraines with aura more than 12 times a year or for more than 12 years.7 The risk may be even higher in women who smoke, use birth control pills, or have high blood pressure.8
What causes migraines?
The exact cause of migraines is not fully understood. The theory is that migraines are related to abnormal activity deep in the brain brought on by internal and external cues, called triggers. This abnormal brain activity causes changes in the size of the blood vessels, which swell up. The nerves in the brain respond to these swollen blood vessels by sending pain signals—a migraine.3 Migraines are associated with blocked-vessel stroke because of this change in blood vessel size and blood flow in the brain, especially during migraines with aura.4-6, 9
Most migraines are triggered by external factors. Some common external triggers include:
- Bright lights
- Smoking or exposure to smoke
- Lack of sleep or too much sleep
- Chocolates, dairy products, nuts, fermented or pickled foods
- Weather changes
Internal factors can also trigger migraines, such as fluctuating hormones in women. Seven out of 10 women report that they have more migraines around their menstrual cycle, usually a couple of days before menstruation begins.2 This may be due to lower estrogen levels during this time.
Migraines tend to be hereditary; between 70% to 80% of migraine sufferers have a family history of migraines.3 This leads some to believe that the heightened sensitivity of the nerves in the brain to certain triggers may be genetic.10