Studies show risk of ischemic stroke increased in women who experienced migraines and was worsened by oral contraceptive use, high blood pressure and smoking.
A number of studies have shown the risk of ischemic stroke was increased in women between the ages of 35-45 who experienced migraine with or without aura and was worsened by oral contraceptive use, high blood pressure and smoking. 'Ischemic,' means a reduced oxygen and blood supply at times due to a clot. The other type of stroke is a, 'hemorrhagic,' stroke which is where a weakened or damaged artery bleeds into nearby tissue. Hemorrhagic stroke is not linked with migraine. Even though several studies have shown an increased risk of stroke in young women with migraine compared to people without migraine, the risk remains very small since stroke is rare in people who are young.
Stroke Risk during a Migraine
Quite understandably, some people are afraid their migraine is a symptom of a stroke. Others worry that they are more at risk of a stroke during a migraine headache. There is little evidence to suggest that a stroke is more likely to happen during a migraine than at any other time; migraines are common. In some people, migraine and stroke appear together, yet the nature of the causal relationship; if any, is hard to firmly establish. 'Migrainous infarction,' is the term given to an ischemic stroke that happens during a migraine.
In a migrainous infarction aura symptoms are prolonged and ischemic stroke is confirmed through a CAT scan. Research; however, suggests that such a stroke would be independent of the migraine itself. It is also possible for a person to have a stroke but for it to have been mistaken for a migraine headache. The migraine aura might mimic transient ischemic attacks (TIA's). In a stroke, headaches similar to migraines can happen.
Stroke and Migraine Statistics
A number of studies have been devoted to migraine as a risk factor for ischemic stroke. Most showed a statistically significant relationship between migraine and ischemic stroke in women under the age of 45. The increase in risk is more marked for migraine with aura than in migraine without aura. The risk is more than tripled by smoking and quadrupled for those who use oral contraceptives. The triple combination of migraine, smoking and oral contraceptive use greatly increases a person's risk. 'Oral contraceptive,' refers to combination estrogen/progesterone pills with fairly high doses of estrogen.
Statistically speaking, information regarding this issue has been around for some time now. A review published in the year 1997 examined some of the studies in terms of 100,000 women per year. It was suggested that in women who were under the age of 35, those who:
By comparison, other studies have suggested that 8 out of 100,000 women each year may die in motor vehicle accidents, while 167 women out of 100,000 may die each year from smoking related issues.
The, 'Women's Healthy Study,' performed in the United States in the year 2004 examined 39,754 female health professionals. During the nine years of the study there were 309 ischemic strokes among these health professionals, so there was a total incidence of 8 ischemic strokes per 100,000 women. The number includes women with and without migraine aura, so it may be seen that while the relative risk is seemingly high, the actual risk is very small.
The study confirmed prior studies suggesting that the association between migraine aura and stroke risk was higher in younger than in older women, meaning women younger than age 55. The higher risk with aura also includes those who have additional medical conditions that increase the risk of stroke and which may be associated with aura symptoms instead of true migraine aura. The conditions include some heart conditions and blood clotting disorders. The diagnosis of migraine and migraine aura was self-reported and is subject to bias.
Migraine with Aura and Increased Risk of Stroke
The mechanism of the increased risk of ischemic stroke in young women with migraine remains unknown. It does not appear to be due to an increase in conventional risk factors such as high blood pressure, diabetes, or increased cholesterol levels. There are frequent reports of discoveries of differences between people with and without migraine; for example, the attention given to patent foramen ovale (PFO) or, 'hole in the heart,' in people with migraine with aura. The characteristics; however, are not consistently found in those with migraine compared with people without migraine and they show no gender difference, so they cannot explain why the increased risk of ischemic stroke in migraine is statistically significant in women who are younger. Some studies suggest that aura is associated with adverse cardiovascular risk profile and prothrombotic factors. Research continues to examine this area in hopes of finding more about the complex relationship between migraine with aura and ischemic stroke and any underlying vascular differences between people with and without migraine.
The Implications of the Research
Despite the underlying mechanism, the practical implications of the increased ischemic stroke risk in young women with migraine with aura are fairly clear - when the low absolute risk and its increase by cigarette smoking are taken into account, the first recommendation is to quit smoking. The World Health Organization confirms the best practice is to contraindicate the combined contraceptive pill for use by women who have migraine with aura. The risk for women with migraine without aura is lower and other risk factors like smoking are much more likely to increase stroke risk than migraine.
In practice; however, given the very low absolute risk of stroke in young women, there is no systematic contraindication to oral contraceptive use, but rather a firm recommendation for not smoking and for the use of low estrogen or progestrogen only pills - especially for women who experience migraine with aura. It is important; however, that women with migraine who are taking oral contraceptives to avoid suddenly stopping them without consulting their doctor.
Being, 'at risk,' of stroke does not mean dying from one. Approximately 25% of those who experience a stroke recover. Another 50% will experience a disability after a stroke.
Older People, Migraine and Stroke
Migraine is considered to be insignificant as a risk factor for stroke in people over the age of 50. The reason why is because the usual risk factors for ischemic stroke are:
These factors tend to combine with each other. Along with advancing age, the risk of stroke due to migraine becomes insignificant in comparison with these other risk factors. Migraine with aura stands out as a stroke risk for younger women because it affects people before the usual and more significant age-related factors apply. Migraine also tends to improve later in a person's life.