Although promising, the finding would
need to be confirmed in further studies before any changes are made to
current practice, the researchers said.
"The results are still rather
preliminary," cautioned senior study author Dr. Alberto Ascherio. His
team presented their report Thursday at the annual meeting of the American Academy of Neurology
in Miami Beach, Fla. "Except for our study, there is not much done yet
in terms of looking at the risk of Parkinson's disease in people who
use NSAIDs."
NSAIDs are nonsteroidal anti-inflammatory
drugs, widely prescribed pain relievers that include such
over-the-counter medications as Aleve, Advil and Motrin, as well as
prescription drugs called cox-2 inhibitors. Two cox-2 inhibitors, Vioxx
and Bextra, have been pulled off the market because of adverse effects
on the cardiovascular system. Ibuprofen is found in both Motrin and
Advil.
Parkinson's, a degenerative nervous
system disorder, typically affects people over the age of 50. A steady
loss of cells producing a powerful brain chemical, dopamine, leads to
motor symptoms including trembling, slowness of movement and impaired
balance. There is no cure for Parkinson's, but certain therapies can
help control symptoms.
Recently, evidence of inflammation in the
brains of people who have died of the disease has led to preliminary
research on whether anti-inflammatory drugs like ibuprofen might help
slow Parkinson's.
"There may be inflammatory changes in the
Parkinson's brain, but they're not very overt," said Dr. Carlos Singer,
an associate professor of neurology and director of movement disorders
at the University of Miami School of Medicine. And he said it's still
unclear how inflammation fits into the overall disease picture.
"It's unclear whether this inflammatory
action is something that is just a consequence of the disease and not
relevant to its progression, whether it could be a causal factor, or
something in between, like an aggravating factor," said Ascherio, an
associate professor of nutrition and epidemiology at the Harvard School
of Public Health and an associate professor of medicine at Harvard Medical School.
A previous study conducted by the same
group showed that people who used non-aspirin NSAIDs regularly had a
lower risk of developing Parkinson's than nonusers. "We found a 45
percent lower risk of Parkinson's among men and women who regularly
took NSAIDs," Ascherio said. "That was the only study of its kind and
we wanted to reproduce the results, because you never know if it is
true or not."
In their current effort, the authors looked at nearly 147,000 people who participated in an American Cancer Society study. During the follow-up period of about eight-and-a-half years, 413 of these participants developed Parkinson's.
The researchers found that people who
regularly used ibuprofen were at 35 percent lower risk of developing
the disease than nonusers. The results were similar in men and in women.
People who took fewer than two tablets a
week had a 27 percent lower risk of developing Parkinson's, compared
with nonusers. Those taking two to 6.9 tablets per week were at 28
percent lower risk, while daily users were at 39 percent lower risk.
People who had taken ibuprofen for longer
periods of time also seemed to have a lower risk, but the effect was
not statistically significant. Those who had taken ibuprofen for less
than two years had a 22 percent reduced risk compared to nonusers;
those who took ibuprofen for two to 4.9 years had a 21 percent reduced
risk, while those taking it for five or more years had a 28 percent
reduced risk.
The authors found no significant
relationship between use of aspirin, other NSAIDs or acetaminophen
(Tylenol) and the risk of developing Parkinson's.
The reason behind ibuprofen's potentially protective effect against Parkinson's is not yet known.
"The results are not totally consistent
in terms of pointing to specific mechanisms," added Ascherio. "We found
that ibuprofen was related to a lower risk, but other NSAIDs that
supposedly act through similar mechanisms were not related."
The other NSAIDs were used by smaller
numbers of people, so this apparent paradox may simply be explained by
lack of study particpants. But it could also be something unique to
ibuprofen. "This would be consistent with parallel work in Alzheimer's disease, and people realizing that all NSAIDs are not equal," Ascherio said.
