NEW YORK (Reuters Health) - People who regularly use ibuprofen to ease their aches and pains may be less likely to develop Parkinson's disease than those who do not use the painkiller, researchers reported Wednesday.
In a study of more than 136,000 U.S. men and women, researchers found that the more ibuprofen tablets people took each week, the lower their odds of developing Parkinson's, a disorder in which movement-regulating brain cells degenerate over time.
Ibuprofen, sold as name-brands like Advil and Motrin in the U.S., is a non-steroidal anti-inflammatory drug (NSAID). But the study found no connection between Parkinson's risk and other NSAIDS, like aspirin or naproxen (Aleve), or with acetaminophen (Tylenol).
Experts caution, however, that the findings do not prove that ibuprofen itself can help ward off Parkinson's.
"It's too early to recommend use of ibuprofen to prevent or treat Parkinson's disease," lead researcher Dr. Xiang Gao, of Harvard Medical School in Boston, told Reuters Health in an email.
Instead, Gao said, the findings lay the groundwork for clinical trials to look at whether the painkiller, which costs only a few cents per pill, might help slow Parkinson's progression.
Such trials, in which patients are randomly assigned to receive a drug or an inactive placebo pill, are necessary to test whether a treatment really works.
The current study, published in the journal Neurology, is an "observational" study, meaning that researchers look at the association between a lifestyle habit, for instance, and a person's disease risk.
"An association does not prove causation," said Dr. James H. Bower, a neurologist at the Mayo Clinic in Rochester, Minnesota, who wrote an editorial published with the study.
"One possible explanation is that ibuprofen does protect against Parkinson's disease," Bower said in an interview. "That's what everyone would hope — that would be very exciting."
"But," he said, "we're not there yet."
And since regular ibuprofen use has risks, like stomach bleeding and kidney damage, no one should start using the drug in the hopes of preventing or treating Parkinson's, Bower cautioned.
But he also praised the study, saying it is "very scientifically sound," and that the researchers' theory on why ibuprofen might be protective is plausible.
Unlike other NSAIDs, ibuprofen acts on a receptor on cells known as PPAR-gamma — which, animal research suggests, may play some role in the Parkinson's disease process. That, Gao's team says, offers one possible explanation for their findings.
The results are based on middle-aged and older adults taking part in two long-running studies of lifestyle habits and health among U.S. medical professionals.
Starting in 1998 and 2000, participants were asked about their use of common painkillers. Over the next 6 years, about two out of every thousand study participants were newly diagnosed with Parkinson's disease.
Overall, Gao's team found, people who regularly used ibuprofen (at least twice a week) were 38 percent less likely than non-users to develop Parkinson's during the study period — with factors like weight, age and smoking and drinking habits taken into account.
There was also evidence that the risk dipped as ibuprofen intake went up. People who said they downed six or more tablets per week had the lowest Parkinson's risk versus non-users.
However, those figures are based on small numbers. Of study participants who developed Parkinson's, only 10 were taking six or more ibuprofen tablets per week at the outset. And only 13 were taking one to 5 pills per week.
There could also be other explanations for the ibuprofen-Parkinson's connection, Bower said.
Constipation and other gastrointestinal complaints can crop up early in Parkinson's development, he pointed out. So it's possible that some people in those early stages avoided ibuprofen because they thought the medication caused or worsened those problems.
It's estimated that up to 1 million Americans are living with Parkinson's disease. No one knows exactly what causes the condition, but it is marked by the gradual destruction of dopamine-producing cells in the brain, leading to symptoms like tremors, rigidity, slowed movement and balance problems.
Researchers generally think that a combination of genetic vulnerability and certain environmental exposures is at work. Just what those exposures might be is uncertain, but studies have linked exposure to toxins such as pesticides and manganese to a higher Parkinson's risk.
On the Web: Neurology, online March 2, 2011.
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