A study was conducted to explore the link between cardiovascular disease and migraines. This prospective study was conducted among Nurses’ Health Study II participants, with follow-ups from 1989 through June 2011.
A baseline of 11,5541 women aged 25-42 years, free of angina and cardiovascular disease, was established. The main outcome measures of the study were major cardiovascular diseases. 17,531 (15.2%) women reported diagnosis of migraine from physicians.
Over 20 years of follow-ups, 1,329 major cardiovascular disease events occurred and 223 women died from cardiovascular disease. After adjustment for potential confounding factors, migraine was associated with an increased risk for major cardiovascular disease.
Few studies have deeply studied the effects of migraines on cardiovascular mortality, particularly in women. However, these results show that migraine should be considered an important factor especially regarding the cardiovascular health of women.
A migraine is a type of headache disorder that affects an estimated of 20% of the American population, at least for some parts of their lives. Women are affected three to four times more than men. Migraine, specifically migraine with aura, has been consistently associated with an increased risk of stroke, including both ischemic and hemorrhagic subtypes.
Despite the disease’s prevalence, little is known on how it causes strokes. Potential links of cardiovascular disease and migraines could be attributed to gene factors, endovascular dysfunction, cortical spreading depolarization, and inflammation.
Most of these factors increase the risk of other vascular diseases. However, with age, the chances of cardiovascular diseases increases exponentially and it becomes difficult to pinpoint this increased risk to migraines. Hence most of these studies need to be conducted on young and healthy individuals.
Few studies have been able to form an association between migraine and any cardiovascular disease events, including ischemic heart disease and cardiovascular death. Due to the risks associated with both cardiovascular disease and migraines, this study would greatly benefit public health.
The data was collected from the Nurses’ Health Study II. It is an ongoing prospective database, established in 1989, of 11, 6430 registered female nurses in the United States, who were 25-42 years old at the baseline.
Information about lifestyles, sexual habits and medical histories was gathered using questionnaires and was updated every two years to keep the data consistent. Also, follow-up questions were continued until 2011. Women who had anginas during the baseline period were excluded.
Additionally, no patient bias was formed and all questionnaires were formed without outside involvement.
During the baseline in 1989 and follow-up questionnaires in 1993 and 1995, women were asked whether they had any migraines. Information on migraine aura, migraine frequency, or migraine-specific drugs was not available. Every two years, women reported any incidence of cardiovascular disease and filled a related questionnaire to confirm the event.
Self-reported incidents were confirmed by physicians. Deaths were reported by family members or looked up using the National Death Index while causes of death were identified using autopsy reports.
The occurrence of non-fatal myocardial infarction was confirmed if symptoms met World Health Organization (WHO) criteria, which required typical symptoms plus either diagnostic electrocardiographic findings or elevated cardiac enzyme concentrations. If myocardial records were unavailable, the researchers considered the possibility of myocardial infarctions if additional info was provided by the individual.
Non-fatal strokes were considered only after meeting The National Survey of Stroke criteria. If the patient had a weaker brain performance after a sudden or rapid onset, the stroke was considered.
Fatal cardiovascular disease was defined as fatal coronary heart disease, fatal stroke, or fatal cardiovascular disease. It was deemed fatal if the cause of death was confirmed via medical records or autopsy reports or if coronary heart disease was listed as the cause of death on the death certificate and there was prior evidence of coronary heart disease in the medical records.
The primary outcome measure was major cardiovascular disease, a combined endpoint of myocardial infarction, stroke, or fatal cardiovascular disease. This measure was considered since it was extensively used in previous studies. Total myocardial infarctions, total strokes, angina/coronary revascularization procedures and cardiovascular disease mortality were considered as possible outcomes.
The researchers calculated personal factors such as cholesterol, diabetes, use of oral contraceptives, alcohol usage, smoking status, body mass index, menopause status, postmenopausal hormone, aspirin use, non-steroidal anti-inflammatory drug use or history of myocardial disease using Cox proportional hazards models with age and a two year follow-up cycle as timescales. This was done to evaluate the association between migraine and the various outcomes, from the return date of the 1989 questionnaire until the date of diagnosis of cardiovascular disease, the date of death, or the end of the follow-up (June 2011), whichever occurred first.
The Results — Cardiovascular Disease
Of the 11, 5541 women in this study, 17, 531 (15.2%) reported being diagnosed with migraines at the baseline by physicians in 1989. An additional 6389 women were newly reported through physician diagnoses on subsequent questionnaires and were classified as having migraines during follow-ups.
Women with migraine were more likely to have an unfavorable cardiovascular risk factor profile, including hypertension, hypercholesterolemia, family history of myocardial infarction, body mass index of 30 or above, and current smoking status. They were also more likely to use aspirin, acetaminophen, and non-steroidal anti-inflammatory drugs.
During the follow-up, a total of 1329 major cardiovascular events occurred, of which 678 were myocardial infarctions, 651 were total strokes, and 203 angina/coronary revascularization procedures occurred. A total of 223 deaths occurred due to cardiovascular disease.
Consistent links were found between cardiovascular disease and migraines, with an approximately 50% increased risk of cardiovascular disease compared to individuals who did not suffer from migraine symptoms. The results of this study were similar to the results of other studies such as the Women’s Health Study.
According to the Women’s Health Study, the increased risk was apparent only for women who reported migraines with auras. In the latest study, information on auras was not available. This study proves the hypothesis that migraines could lead to the development of cardiovascular disease.
Currently no clear scientific reasons have been identified that could explain the increased risk of cardiovascular disease and mortality among patients with migraine, and no proof exists on whether prevention of migraine attacks reduces these risks. An urgent need exists to understand the biological processes involved and to provide preventive solutions for patients. Hence more research needs to be done to further explore this connection.