Migraine frequency and risk of cardiovascular disease in women
Eve Klein, MD and
David Spencer, MD
Previous studies have shown that people who suffer from migraineheadaches are more likely to also have cardiovascular disease,such as stroke and heart attack.1,2 We do not know, however,exactly how migraines are related to cardiovascular disease.We believe that migraines cause changes in blood flow in thebrain. Strokes occur when a part of the brain receives no bloodflow at all, and heart attacks occur when the heart muscle isstarved of blood. Because both migraines and cardiovasculardisease involve changes in blood flow, it is reasonable to thinkthat people who have more frequent migraines would be at higherrisk for strokes and heart attacks.
The authors of a study published in this issue of Neurology®reviewed the records of 27,798 female health professionals aged45 and older with no known cardiovascular disease.3 Of thesewomen, 3,568 had migraines. Compared with other studies of thistype, this is a large number of subjects; having more subjectsmakes a study more reliable. Medical information about thesewomen was recorded during a 12-year period. The researchersasked whether the women experienced migraines less than oncea month, every month, or every week. They also tracked whetherthe women developed any cardiovascular disease during the 12-yearperiod. Using this information, the authors compared the riskof cardiovascular disease with the frequency of migraine todetermine how the two might be related.
The authors found very different results depending on whetheror not women had migraine auras. A migraine aura is an earlywarning symptom of a migraine that often involves changes invision. In women whose migraines did not include an aura, theyfound no significant increase in risk of cardiovascular diseasecompared with women who had no migraines at all. However, whenthe authors looked only at women whose migraines included anaura, they found that these women did have an increased riskof cardiovascular disease. Women whose migraines with aura occurredless than once a month had more than twice the risk of heartattack than women without migraines and also had elevated strokerisk. Women whose migraines with aura occurred at least oncea week had more than 4 times the risk of stroke compared towomen without migraines.
Although these changes in risk sound big, it is important toremember that the actual numbers of people who developed cardiovasculardisease are small. For example, of the 180 women with weeklymigraines, only 2 had heart attacks and 4 suffered strokes duringthe 12 years of the study. Also important to remember is thatthere are many other risk factors for developing strokes andheart attacks and that the women in this study did not haveequal risk factors. For example, the women who had weekly migrainesalso had lower cholesterol, less smoking, and less alcohol use,but higher blood pressure and more hormone replacement use thanthe women with less frequent or no migraines. The authors usedstatistics to try to control for these differences, but thisuneven balance of risk factors could make the results less reliable.
This information is important for patients and their loved onesbecause it tells us that some women with migraines—especiallythose with aura—may be at higher risk of heart attackand stroke than other women. Until now, doctors have treatedmigraines with the goal of making patients comfortable, decreasingtheir suffering, and allowing them a higher quality of life.Some people find other ways to cope with their migraines andchoose not to use medication to reduce the headaches. If migraineswith aura, however, are not only painful, but also lead to higherrisk of stroke and heart attack, then doctors and patients mighthave another very important reason to treat migraines. We donot yet know whether treatments used to prevent migraines wouldalso reduce the risk of heart attack and stroke. If this istrue, then we need to be aware that leaving migraines untreatedis not only uncomfortable, but also dangerous. Awareness ofincreased stroke risk might also signal patients with migrainesto pay special attention to other cardiovascular risk factorssuch as high blood pressure, high cholesterol, and smoking.
A migraine headache is usually a severe, throbbing headachethat is typically on one side of the head and may last for hours.It is 3 times more common in women than men.4 Often migraineheadaches are accompanied by nausea and sometimes vomiting.Generally, when someone is experiencing a migraine, he or shewill feel the need to lie down in a dark, quiet place untilthe headache ends. The cause of migraine is not well understood,but it is believed that abnormal brain or nerve activity causesblood vessels in the brain to both dilate and constrict, leadingto the headache. Some migraines begin with what is called anaura. Auras usually consist of strange visions of light or color.Occasionally an aura may also involve a familiar smell or tasteor weakness or numbness on one side of the body. After the aura,the migraine headache begins.
An estimated 28 million Americans experience migraines. Specifically,that is 17% of American women and 6% of American men.5 Headacheis the most common reason why patients see a neurologist, andmigraine is the most common type of headache that neurologistssee.
The cause of migraine is not well understood, but it is believedthat blood vessels in the brain both dilate and constrict, leadingto the headache. During an aura, brain cells become overexcited,and this increase in brain activity leads to the blood vesselchanges, which cause the headache. Sometimes the migraine disorderis hereditary, passed down through families. Often triggerssuch as stress, temperature changes, hormonal changes, or changesin diet cause a migraine to start.
Many different medication treatments are available for migraines.Some work to stop migraines after they start. Others are takenevery day to prevent future migraines. Migraine treatments havevarying side effects. Depending on a patient's migraine frequencyand severity and other medical conditions, doctors may recommenddifferent migraine medications. Certain types of mental healthcounseling aimed at reducing stress levels to control headachesmay also help reduce migraines.
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