NSAIDs Play Protective Role In Parkinson Disease Development – Study

A just-published study indicating non-steroidal anti-inflammatory drugs may help protect against the development of Parkinson Disease does not lend itself to extrapolation to the general public, Mya Scheiss, MD, University of Texas, Houston, said in an accompanying editorial.

The trial, appearing in the August Archives of Neurology, "does not allow specification of the duration and degree of exposure required to achieve maximum benefit for the population as a whole, information with important public health implications that will require further analysis," Scheiss asserted.

Conversely, "it is also likely that benefits of even greater magnitude might be demonstrable if this intervention were applied to the same population as it aged beyond 75 years," she noted.

Conducted by Honglei Chen, MD/PhD, Harvard School of Public Health, et al., the trial showed men and women who took NSAIDs more than twice per week were less likely than non-users to develop Parkinson Disease.

Scheiss questioned whether the data culled from the study "compels" physicians to urge their patients to take NSAIDs for primary prevention of the disease. She further questioned whether only the NSAIDs evaluated in the study be recommended.

Despite Scheiss' criticism, she does believe that "short of evidence from a randomized controlled clinical trial, this study design provides the most compelling evidence for a clinically relevant benefit of NSAIDs in preventing PD."

After identifying 415 PD cases (including 179 women and 236 men), study investigators found "regular use of non-aspirin NSAIDS at baseline was associated with lower risk of PD...compared with non-regular users."

"The association was statistically significant when the results from men and women were pooled," noted Chen, et al.

The researchers collected data from the Health Professionals Follow-Up Study, where participants responded to questionnaires sent every two years between 1986 and 1994 regarding aspirin and other NSAID use. Information also was gathered from the Nurses Health Study, in which the surveys including questions on NSAID use were sent less regularly.

Investigators obtained information about participants' use of various NSAIDs, including naproxen, indomethacin, diflunisal and ibuprofen in men, as well as tolmetin sodium and sulindac for women. The dosage amounts for the drugs were not questioned.

In analyzing results, Chen et al. noted "for non-aspirin NSAIDS, regular use at baseline...was considered as the primary exposure, because this definition could be most consistently applied in both cohorts."

While the results of NSAID use seemed positive, aspirin use proved less promising; baseline regular use bore no relationship to development of the disease compared with non-regular users, investigators concluded.

"However, in men and women, taking two or more tablets of aspirin per day was associated with a lower risk of PD," researchers said. Participants who took lower doses of aspirin did not show the same results.

Although researchers compared acetaminophen with NSAIDS and aspirin, they found no relationship between risk and disease development in either cohort.

"In these large prospective cohort studies, we found a 45% lower risk of PD among regular users of non-aspirin NSAIDs compared with non-users," Chen and colleagues summarize, adding the study's prospective design made both the biasing of results and "misclassification of baseline exposures" unlikely.

Still, researchers note the presence of caffeine in some over-the-counter NSAID tablets "could hypothetically contribute to their protective effect," although they point out the presence of caffeine is very small and is unlikely to have such a significant effect.

The theory is further weakened by the fact that the "results on NSAIDs were similar in men and women, whereas caffeine was inversely associated with PD risk only among men." Chen et al. therefore suggest the "protective role of NSAIDs in the central nervous system...seems likely and should be addressed in future investigations."