Mid-Life Migraine Sufferers More Likely To Develop Parkinson’s: Study

Mid-life migraines with aura may be an indication of Parkinson's disease to come, a new study finds. Photo courtesy of Shutterstock

NEW YORK (Reuters Health) - People who experience migraines with aura during middle age are more than twice as likely as those without headaches to be diagnosed with Parkinson’s disease later in life, according to a new study.

Whether or not you’ve had headaches, Parkinson’s disease is still rare, lead author Ann I. Scher told Reuters Health.

“This definitely should not alarm people,” said Scher, of the Uniformed Services University and the National Institute on Aging in Bethesda, Maryland.

“Even though the risk was doubled, it was still uncommon, so people should not be unduly concerned,” she said.

Nonetheless, the results are novel and should be interesting to scientists and researchers, she said.

Past studies have linked migraine with movement disorders like Parkinson’s and restless legs syndrome, in part based on shared features such as dysfunction in the brain’s responses to the neurotransmitter dopamine, Scher and her colleagues note in the journal Neurology.

But those studies were limited to groups with specific disorders, so she and her team wanted to look at a broader population sample over time to see if migraine was linked to later Parkinson’s.

The researchers used data from an existing study started by the Icelandic Heart Association in 1967, which included people born between 1907 and 1935.

The men and women randomly selected to be part of the study group answered questions about headache symptoms at an average age of 51. If they reported at least one headache per month, they answered follow-up questions to categorize the type of headache based on migraine symptoms like nausea, pain on one side of the head, sensitivity to light, visual disturbance before or during the headache and numbness.

Nonmigraine headaches include none, or at most one, of those symptoms. Someone who has migraine without aura might experience nausea, one-sided pain or sensitivity to light. Migraines with aura include visual disturbance or numbness in addition to any of the other symptoms.

Of the 5,620 people included in the study, almost 4,000 had no headaches, 1,028 reported non-migraine headaches, 430 had migraines with aura and 238 had migraines without aura.

Typically, Scher said, about a third of migraine sufferers have migraines with aura.

In an interview at around age 77, participants answered questions about movement disorder symptoms like hand tremor, weak voice, stiff gait, arm rigidity, slowed arm movement or smaller handwriting.

Almost nine percent of the group reported four or more movement disorder symptoms.

All movement symptoms were more common for people who reported migraine with aura earlier in life, especially hand tremor and arm rigidity.

Most symptoms were also more common for people with migraine without aura, but the connection was stronger for those with aura, according to study results.

Only 1.2 percent of the group as a whole reported being diagnosed with Parkinson’s disease. Those who had reported migraine with aura were two and a half times more likely to be diagnosed with Parkinson’s than those with no headaches.

While Parkinson’s disease was strongly related to certain types of headaches, restless leg syndrome was more common for people with all types of headaches. The same connection has been found before, Scher said.

"You wonder, because it’s a population based study and done some time ago, whether some of those labeled as migraine without aura did have aura,” said Dr. Peter J. Goadsby, a headache diagnosis and treatment specialist at the University of California, San Francisco, who was not part of the new study.

He has almost never encountered a patient with headaches and Parkinson’s disease, but it is interesting to consider headaches earlier in life and Parkinsonism later, he told Reuters Health by phone.

People with migraines with aura tend to be at increased risk of stroke, and some types of Parkinsonism are also related to stroke or stroke risk, but based on these results, stroke doesn’t explain the connection, Scher said.

“We don’t think it’s the medications they’re taking either,” she said.

It could be that people with migraines and Parkinson’s may share a genetic trait that explains the connection, or it may be that those with migraines tend to have experienced more head injuries, which may then increase Parkinson’s risk, she said.

“This is all speculation,” Scher said. “It could be more than one thing and they could work together - genes and environment.”

It would be too speculative to suggest what people with headaches could do to reduce their risk of Parkinson’s disease later in life, she said.

Although the study does not have immediate clinical applications, it may have implications for developing new therapies to treat migraine, Goadsby said.

“I’m really hopeful that this will someday lead to better understanding of what migraine is,” Scher said.

SOURCE: http://bit.ly/NwhhyY Neurology, online September 17, 2014.

(By Kathryn Doyle)

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