Smoking, caffeine, and nonsteroidal anti-inflammatory drugs in families with Parkinson disease

Objective: To assess associations between Parkinson disease (PD) and putatively protective factors - smoking, caffeine (coffee, tea, and soft drinks), and nonsteroidal anti-inflammatory drugs (aspirin, ibuprofen, and naproxen). Design: Family-based case-control study. Setting: Academic medical center clinic. Participants: A total of 356 case subjects and 317 family controls who self-reported environmental exposures. Main Outcome Measures: Associations between PD and environmental measures (history, status, dosage, duration, and intensity) of smoking, coffee, caffeine, nonsteroidal anti-inflammatory drugs, and nonaspirin nonsteroidal anti-inflammatory drugs were examined using generalized estimating equations with an independent correlation matrix while controlling for age and sex. Results: Individuals withPDwere significantly less likely to report ever smoking (odds ratio = 0.56; 95% confidence interval, 0.41-0.78). Additional measures of smoking revealed significant inverse associations with PD (P<.05) and trends in odds ratios (P<.005). Increasing intensity of coffee drinking was inversely associated with PD (test for trendP = .05). Increasing dosage (trend P = .009) and intensity (trend P = .01) of total caffeine consumption were also inversely associated, with high dosage presenting a significant inverse association for PD (odds ratio = 0.58; 95% confidence interval, 0.34-0.99). There were no significant associations between nonsteroidal anti-inflammatory drugs and PD. Conclusions: Inverse associations of smoking and caffeine were corroborated using families with PD, thus emphasizing smoking and caffeine as important covariates to consider in genetic studies of PD.