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Rapid Responses: Rapid Responses published:
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Migraine and stroke
- Rizaldy Pinzon (13 March 2009)
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Deeply flawed data
- Alexander Mauskop (18 March 2009)
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Increased blood viscosity links migraines to stroke and myocardial infarction.
- Les O. Simpson (7 April 2009)
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Re: Deeply flawed data
- Cheryl D Bushnell (7 April 2009)
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Rizaldy Pinzon, Neurologist Bethesda hospital Yogyakarta Indonesia 55224
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This interesting study confirmed that people who suffer from migraine may have a slightly greater risk of stroke. Migraines during pregnancy were linked to a 15-fold increased risk of stroke. Migraines also tripled the risk of blood clots in the veins and doubled the risk of heart disease. Vascular risk factors were also strongly associated with migraines. These included diabetes, high blood pressure and cigarette smoking. However, stroke is generally caused by a number of factors working in combination. The higher risk for stroke may be related to reduced blood flow in the brain during a migraine, but the exact mechanism for this association is unknown. A theory suggest that strokes can occur as the result of a syndrome called "reversible cerebral vaso-constriction syndrome" (RCV). Other factors which can increase the risk of stroke include the use of oral contraceptives and cigarette smoking should be concerned. A young woman who experiences frequent migraine should minimize the risk of stroke by quitting cigarettes and using other forms of birth control.Lifestyle modification should be done in people with classic migraine. They should stop smoking, eat fruit and vegetables and have high blood pressure control Competing interests: None declared |
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Alexander Mauskop, Director New York Headache Center, 10021
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The large amount of data and the statistical analyses in this paper look impressive and unfortunately may fool many readers into believing the conclusions made by the authors. The authors do acknowledge that the discharge diagnostic codes miss many patients who suffer from migraine headaches. This diagnosis is not only missed upon discharge, but it is an established fact that migraine is significantly underdiagnosed by the majority of primary care doctors. Obstetricians are not likely to do a better job in distinguishing sinus and tension-type headaches from migraines, or diagnosing a migraine aura, particularly when managing a pregnant woman in the hospital. It is true that migraines improve in pregnancy, but considering that about 18% of women suffer from migraine headaches, it is hard to believe that only one in 100 of these women will continue having migraines during pregnancy. Obviously, when a complication, such as stroke occurs the diagnosis of migraine is much more likely to be recorded than when no complications occur. The authors provide many disclaimers and state that "On the basis of the select group of pregnant women with migraines coded during the hospital admission, this may not represent the population of women with migraine as a whole". Nevertheless, they go on to present and analyze this highly inaccurate data and even draw conclusions. It is very unfortunate that the publicity associated with this paper (I first saw it reported on Yahoo.com) will cause unnecessary anxiety to millions of pregnant women. Competing interests: None declared |
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Les O. Simpson, retired experimental pathologist Dunedin, New Zealand 9077
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This study of pregnancy-related migraines draws attention to the consequences of disregarding published information in the field of blood rheology. Unfortunately the science of haemorehology has failed to gain clinical recognition, but this does not alter the fact that increased blood viscosity is an important pathological factor in many chronic disorders. An example of this lack of recognition is the statement, "Women with peripartum migraines were also more likely to have vascular risk factors such as diabetes,hypertension and tobacco smoking, etc" without apparent recognition that all three factors are associated with increased blood viscosity. The statement, "We found that women with pre- eclampsia were twice as likely to have peripartum migraine as those without pre-eclampsia," shows a lack of awareness of those published studies which link pre-eclampsia with increased blood viscosity. Several studies from workers in European countries have used SPECT to show focal hypoperfusion during pain-free periods, with more widespread hypoperfusion during attacks. A Danish study noted, "The first observable event was a decrease of regional cerebral blood flow, posteriorly in one cerebral hemisphere. Further development of this pathological process was accompanied by aura symptoms. Thereafter headache occurred while cerebral blood flow remained decreased." An Italian group noted that migraineurs had significantly reduced red cell filterability index and significant increases in low shear rate blood and plasma viscosity. Such changes could contribute to the reduced blood flow rate reported by the Danish group. The role of diet in migraine has been investigated by several groups and they draw attention to the adverse effects of chocolate, cheese, citrus fruits, milk nuts and cola drinks. One study concluded, "Our study suggests that foods may trigger not only migraine, but also tension type headache attacks." An adverse response to a food will alter the internal environment sufficiently to cause an increase in blood viscosity and reduce red cell deformability. As impaired cerebral blood flow is associated with cognitive problems in other disorders, the results of a Spanish study are relevant. Areas of brain hypoperfusion were found in patients with poor results from tests of verbal or visual memory. A SPECT study reported from a group in Turkey noted that, "The SPECT images revealed clear interhemispheric asymmetry in the upper frontal and occipital parts of the brain in migraineurs. It is suggested that an impaired regional cerebral autoregulation may exist even during headache-free intervals in patients suffering from migraine." Thus there are good reasons to conclude that migraines are associated with both increased blood viscosity and poorly deformable red cells, and that such changes are manifested as impaired blood flow. This conclusion seems to imply that migraine occurs only in genetically predisposed individuals. Therefore, when exposed to other conditions with increased blood viscosity, the effects would be cumulative. For example, there are many reports which show that smoking is associated with increased blood viscosity and poorly deformable red cells. So it is not surprising that the NCPP study noted that pregnant migraineurs who smoked had a higher prevalence of heart disease than non-smoking pregnant migraineurs. It was stated, "We found that women with pre-eclampsia were twice as likely to have peripartum migraines as those without pre-eclampsia." But there are several reports which record that pre-eclampsia is associated with increased blood viscosity. For example, Hobbs et al (1) reported in 1982 that blood viscosity was increased in patients with pre-eclampsia. The English translation of the abstract of a Japanese study stated, "In severe pre-eclampsia subjects, viscosity was significantly higher than in normal pregnancy cases. The natural decrease in peripheral blood flow resulting from elevated viscosity threatens the lives of both mother and foetus." Similar findings have been reported by others. A significant literature documents the roles of blood viscosity and poorly deformable red cells in cardiovascular and cerebrovascular disorders and that literature has been summarised. (2) It is concluded that the importance of recognising the role of blood viscosity in chronic disorders is that it draws attention to potentially helpful treatments. For example, Bic et al (3) found that a low-fat diet, similar to the Swank low-fat diet for multiple sclerosis, had a beneficial effect on migraine headaches. It was stated, "The decreased dietary fat intervention was associated with statistically significant decreases in headache frequency, duration and medication intake (all p< 0.0001)." Later it was stated, "There was a significant positive correlation between baseline dietary fat intake and headache frequency (r=.44, p=0.02)" It is likely that the reduced fat intake would be associated with lower blood viscosity. Gibson (4) stated, "There appears to be sufficient evidence to suggest that patients at risk from heart disease could benefit from a low dose (1 to 6 g/day) of fish oil in conjunction with a prudent diet." Such a regimen could be beneficial for migraineurs. It is concluded that studies involving chronic disorders which do not take cognisance of the haemorheological situation may draw conclusions which have little relevance to sufferers and their medical advisors. References. 1. Hobbs JB, Oats JN, Palmer AA, et al. Whole blood viscosity in preeclampsia. Am J Obstet Gynecol 1982;142:288-92. 2. Simpson LO. Blood viscosity factors - the missing dimension in modern medicine. The Mumford Institute, Highlands, New Jersey, 2008. 3. Bic Z, Blix GG, Hopp HP, et al. The influence of a low- fat diet on incidence and severity of migraine headaches. J Womens Health Gender Based Med 1999;8:623-30. 4. Gibson RA. The effects of diets containing fish and fish oils on disease risk factors in humans. Aust NZ J Med 1988;18: 713-22. Competing interests: None declared |
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Cheryl D Bushnell, Associate Professor of Neurology Wake Forest University Health Sciences
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As the first author of this paper I would like to respond to the criticisms brought forth by Dr. Mauskop. We clearly stated in the abstract and the body of the paper that our conclusions only represent women with active migraines during hospitalization. These results should not be extrapolated to all women with migraines or those who have been misdiagnosed or the diagnosis was not recognized. Therefore we are not presenting "inaccurate" data--the data are what they are. We were very careful to try to dispel alarm, as well, especially with the BMJ press release. How other news services, such as Yahoo, represent our data is beyond our control, and they did not interview me or my coauthors directly. Lastly, to reiterate our points, the following is the main point of our conclusions: "To summarise, we identified a coexistence of diagnoses of peripartum migraine with vascular diseases and vascular risk factors during pregnancy in a subpopulation of women with active migraine during admission to hospital. Obstetricians, general practitioners, and neurologists should all realise that these results do not apply to every woman with migraine during pregnancy. However, for pregnant women admitted to hospital with active migraines , modifiable cardiovascular risk factors and complications of pregnancy such as pre-eclampsia, should be recognised and treated." Competing interests: None declared |
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