Abstract
BACKGROUND AND AIM: Air pollution exposure may increase the risk of Parkinson’s Disease (PD). We assessed associations between long-term traffic-related air pollution exposures and PD in central California. METHOD: We generated air pollution exposures for 688 PD patients and 851 population controls enrolled in the Parkinson’s, Environment and Genes (PEG) studies 1 and 2. First, we estimated annual average carbon monoxide (CO) concentrations between 1981-2016 using the California Line Source Dispersion Model, version 4 (CALINE4) to model local traffic sources and, additionally, fine particulate matter (PM2.5) concentrations between 2000-2016 based on a high-resolution geoscience-derived model. Exposures were assessed as 10-year averaged CO and 5-year averaged PM2.5 prior to a PD diagnosis and a reference date in controls. We used logistic regression models to estimate odds ratios (OR) and 95% confidence intervals (95%CI), adjusting for age, sex, race, education, and study wave. RESULTS: For CO, each interquartile range (IQR) increase in 10-year average exposure prior to diagnosis was found to be associated with an OR of 1.06 (95% CI: 1.01-1.11) for residential and of 1.08 (0.99-1.18) for occupational address-based exposures. A per IQR increase in 5-year average PM2.5 prior to PD also increased the OR for PD at occupational address (OR=1.26; 95% CI 0.96-1.67). Associations were similar for 5- and 15-year exposure averages and were robust to adjustment for smoking or pesticide exposures. CONCLUSIONS: We found consistent evidence for positive associations between PD and long-term exposure to local traffic-related air pollution in central California measured by CO and PM2.5 at home and workplace addresses.