Migraine tends to affect people from 15-55 years of age. Women are much more likely to experience them than men.
Study author Ann I. Scher, of the Uniformed Services University in Bethesda, MD, identifies migraine as the most common brain disorder in both men and women, as well as being a condition that has previously been linked to both cerebrovascular and heart disease.
"This new possible association is one more reason research is needed to understand, prevent and treat the condition," she says.
Migraine headaches result from a combination of blood vessel enlargement and the release of chemicals from nerve fibers that coil around these blood vessels. Migraines typically produce moderate to severe pain and are sometimes accompanied by auras - perceptual disturbances such as blurred vision that can precede a headache.
Approximately 12% of Americans suffer from migraine headaches. They are also associated with several other conditions, such as stroke and fibromyalgia. Their prevalence and these associations make them a condition of scientific interest to research.
The study was funded by the National Institutes of Health, National Institute on Aging, Icelandic Heart Association and the Icelandic Parliament, and it is published in Neurology, the journal of the American Academy of Neurology (AAN).
For the study, the researchers followed a population-based cohort of 5,620 people from the Icelandic AGES-Reykjavik study for a period of 25 years. The participants were aged from 33-65 years at the beginning of the study. After the study period, the researchers assessed the participants for Parkinson's disease and restless legs syndrome (RLS).
At the beginning of the study, 1,028 of the participants had headaches without migraine symptoms, 238 had migraine without aura and 430 had migraine with aura.
The researchers found that the participants who had migraine with aura were over two times more likely to develop Parkinson's disease than those with no symptoms of migraine. Only 1.1% of participants who did not experience headaches were diagnosed with the condition, compared with 2.4% of those with migraine with aura.
People with migraine with aura were also around 3.6 times more likely to report at least four of the six symptoms of Parkinson's, and people with migraine without aura were 2.3 times more likely.
The overall percentage rates at which Parkinson's symptoms were observed were found to be as follows:
- In people with migraine with aura: 19.7%
- In people with migraine without aura: 12.6%
- In people with no headaches at all: 7.5%.
In addition to this, the study observed that women with migraine with aura were more likely to have a family history of Parkinson's disease than those who did not have headaches. Risk of RLS was found to increase for all types of headache.
Possible cause of migraine?
Scher believes that a neurological explanation could be behind her team's findings:
"A dysfunction in the brain messenger dopamine is common to both Parkinson's and RLS, and has been hypothesized as a possible cause of migraine for many years. Symptoms of migraine such as excessive yawning, nausea and vomiting are thought to be related to dopamine receptor stimulation."
She says that the findings should lead to future investigations, and that "more research should focus on exploring this possible link through genetic studies."
The findings suggest that there may be some common ground between Parkinson's and migraine - the conditions of which are not well known - and further research in this direction may be able to shed further light on these debilitating diseases.
Recently, Medical News Today reported on a phone app that could measure Parkinson's progression in its users.