Background: Neuroinflammation may contribute to the pathogenesis of Parkinson disease (PD). Use of nonsteroidal anti-inflammatory drugs (NSAID) in general, and possibly ibuprofen in particular, has been shown to be related to lower PD risk in previous epidemiologic studies.

Methods: We prospectively examined whether use of ibuprofen or other NSAIDs is associated with lower PD risk among 136,197 participants in the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS) free of PD at baseline (1998 for NHS and 2000 for HPFS). NSAIDs use was assessed via questionnaire. Results were combined in a meta-analysis with those of published prospective investigations.

Results: We identified 291 incident PD cases during 6 years of follow-up. Users of ibuprofen had a significantly lower PD risk than nonusers (relative risk [RR], adjusted for age, smoking, caffeine, and other covariates = 0.62; 95% confidence interval [CI] 0.42-0.93; p = 0.02). There was a dose-response relationship between tablets of ibuprofen taken per week and PD risk (p trend = 0.01). In contrast, PD risk was not significantly related to use of aspirin (RR = 0.99; 95% CI 0.78-1.26), other NSAIDs (RR = 1.26; 95% CI 0.86-1.84), or acetaminophen (RR = 0.86; 95% CI 0.62-1.18). Similar results were obtained in the meta-analyses: the pooled RR was 0.73 (95% CI 0.63-0.85; p < 0.0001) for ibuprofen use, whereas use of other types of analgesics was not associated with lower PD risk.

Conclusions: The association between use of ibuprofen and lower PD risks, not shared by other NSAIDs or acetaminophen, suggests ibuprofen should be further investigated as a potential neuroprotective agent against PD.