Sometimes, you just can’t win.
Much clinical research has suggested that women who suffer from migraines with auras are at increased risk for both strokes in the brain as well as heart attacks. We know this.
We also know that in general people with risk factors such as smoking, high total cholesterol, low levels of good cholesterol and high blood pressure are more likely to have heart attacks and stroke.
The British Medical Journal (BMJ) one of the most respected medical journals in the world reported a very large American study that has looked at the risk of developing a stroke in the brain or a heart attack if you are a woman who suffers from migraines with auras.
The study was a part of a much larger longstanding study known as “Women’s Health Study” that was designed as a randomized trial of low dose aspirin and vitamin E supplementation for the primary prevention (preventing the first occurrence as opposed to preventing a recurrence) of cardiovascular disease and cancer in initially healthy women. The trial included 39,876 female health care professionals aged 45 years or older who were followed for an average of 10 years (For the results of the larger trial, see the attached newsletter from 2005).
The Women’s Health Study has evolved into one of the largest and longest running observational studies of women’s health in the US thanks to the ongoing commitment of the participants. Although the randomized portion of the trial is over, women continue to provide annual health history every year.
For the migraine data analysis, 27,519 cardiovascular disease free women were available with baseline information about their risk factor score and their migraine status. Researchers followed them over the subsequent decade and collected information about cardiovascular events and strokes that occurred during the follow up period.
5074 (18.4%) women reported a history of migraine and 3577 (13%) reported attacks in the past year (Active migraines). 1418 (39.6% of the 3577) reported migraines with auras.
Active migraine with aura patients had a twofold increase in the odds of developing cardiovascular disease, heart attacks or stroke.
The pattern of increased risk was strikingly different between Heart attacks and Strokes for these women (who had migraines with auras).
As you would expect, the higher the levels of risk factors for heart disease, the higher the odds of developing a heart attack.
However, women with the lowest levels of risk factors for cardiovascular disease had the highest risk (odds) of having a stroke. The lowest risk factor group had four times the odds of developing a stroke compared to the highest risk factor group.
Thats not a misprint. The lower your cardiac risk, the higher your stroke risk.
There is more. Upon further analysis, the youngest women had the highest stroke risk and women over 65 had no increased risk. Women between the ages of 45-49 had over five times the odds of having a stroke.
We still aren’t done. Women with lower cholesterol (yes, lower) had four times the odds of developing a stroke, and the levels of good cholesterol did not contribute to this result.
Finally, women with the lowest blood pressures had the highest risk for stroke, about five times the odds of the women with higher blood pressures.
Lets recap. If you are a woman who suffers from migraines with auras, your risk of stroke is higher (much higher) if,
1. You have a low level of cardiac risk factors for heart disease.
2. You have lower total cholesterol levels regardless of your levels of good cholesterol.
3. You are younger.
3. You have low blood pressure.
What explains these results?
The study was not designed to answer the causative question of course but the authors discussed some possibilities.
Its possible that the cause of strokes in women suffering from migraines is different from why strokes occur in other patients. Perhaps, its not related to the deposition of fat in the blood vessels of the brain (atherosclerosis) but due to low pressure of the blood supply, causing less oxygen to be delivered to the brain and because of small, sometimes microscopic clots (called emboli) that block the smaller arteries supplying blood and oxygen to the brain. Since the risk factors measured in this study were specific for heart disease, its possible that the occurrence of strokes in these women was not adequately explained by those factors.
Either way, it’s a sobering thought.
Sometimes you just can’t win.
References:
1. Women’s Health Study: http://whs.bwh.harvard.edu/methods.html
2. Kurth T., Schurks M., Logroscino G., Gaziano JM., Buring JE. Migraine, vascular risk, and cardiovascular events in women:prospective cohort study. BMJ. 2008;337:a636 doi: 10.1136/bmj.a636
Barely Worth The Headache 