Migraines Linked to Brain Lesions and Increased Risk of Stroke in Women

Migraine headaches affect approximately 17 percent of the population at sometime during their life, accounting for more than 1 billion people who suffer from the condition worldwide. American and European studies have shown that 6-8 percent of men and 15-18 percent of women experience migraine every year. The significantly higher rates among women are hormonally driven.

According to a new report published in the Journal of the American Medical Association, women who experience migraines accompanied by a visual disturbance known as an aura, have an increased risk of sustaining long-term microscopic damage to brain tissue that is important to both coordination and the senses. In addition, a second study appearing in the journal Neurology revealed that women who experience frequent migraines along with an aura, have a four times greater likelihood of suffering a stroke in later years than women without migraines. The finding supports previous studies that suggest an association between migraines and stroke.

A migraine headache is most commonly experienced as a throbbing pain that is felt only on one side of the head. These headaches are caused by abnormal brain activity that may be triggered by stress, certain foods, environmental factors, or other factors. The exact chain of events that set off migraines remains unknown. Symptoms accompanying the head pain may include nausea, vomiting and sensitivity to light.

Although scientists once believed that migraines were caused by changes in blood vessels within the brain, most medical experts now believe the condition begins in the brain itself and involves various nerve pathways and chemicals. The changes affect blood flow in the brain and surrounding tissues.

Some migraine sufferers experience attacks accompanied by an aura that causes vision disturbances such as arcs of sparkling light, zigzag lines, blurry spots or loss of vision.

In the first study, Lenore Launer, a neuroepidemiologist at the National Institute on Aging, analyzed a registry of data on over 4,000 people in Iceland in which their health has been followed since 1967. Magnetic resonance imaging (MRI) was performed on the Icelandic people 25 years after the registry began to document evidence of tiny brain lesions.

The researchers found that 23 percent of women having history of migraines with aura had suffered microscopic brain damage, whereas only 15 percent of women with no history of migraines had evidence of the brain lesions. This led to the determination that the women in the migraine-with-aura group were 1.5 times more likely to develop lesions than other women in the registry.

Launer acknowledged that the findings offer no proof of migraine with aura directly causing brain damage, nor do they determine what the risks of having the lesions might be. She says, “These look like very tiny strokes, but we don’t know what the functional consequences of these lesions are.” However, she noted that if a link between migraines and lesions is shown, the finding could disprove past theories that migraines are short-lived headaches that have no lasting effects.

Tobias Kurth, a neurologist and epidemiologist at INSERM, the French national health and medical research agency in Paris, France and colleagues, conducted the second study. This group of researchers analyzed data on over 27,000 U.S. women, including more than 2,500 who suffered from migraines, and a total of 1,095 who also experienced auras. During the 12 years of the study, those who had a history of experiencing auras once a week or more were discovered to be four times as likely to suffer a stroke than women who had no migraines.

Kurth pointed out that although the incidence of stroke in women with migraines with aura in the study was higher than that of women who had no migraines, it was still very low at a risk of only 3 percent. He also noted that the study does not reveal whether migraines are causally connected to strokes or vascular damage by any known biological mechanism.