Traffic-related air pollution, road traffic noise, and Parkinson's disease: Evaluations in two Dutch cohort studies.

Background: Environmental factors such as air pollution have been associated with Parkinson's disease (PD), but findings have been inconsistent. We investigated the association between exposure to several air pollutants, road traffic noise, and PD risk in two Dutch cohorts.
Methods: Data from 50,087 participants from two Dutch population-based cohort studies, European Prospective Investigation into Cancer and Nutrition in the Netherlands and Arbeid, Milieu en Gezondheid Onderzoek were analyzed. In these cohorts, 235 PD cases were ascertained based on a previously validated algorithm combining self-reported information (diagnosis, medication, and symptoms) and registry data. We assigned the following traffic-related exposures to residential addresses at baseline: NO _2, NO _x , particulate matter (PM) _{2.5absorbance} (as a marker for black carbon exposure), PM with aerodynamic diameter ≤2.5 µm (PM _2.5 ), ≤10 µm (PM ₁₀ ), PM _coarse (size fraction 2.5-10 µm), ultrafine particles <0.1 µm (UFP), and road traffic noise (L _den ). Logistic regression models were applied to investigate the associations with PD, adjusted for possible confounders.
Results: Both single- and two-pollutant models indicated associations between exposure to NO _x , road traffic noise, and increasing odds of developing PD. Odds ratios of fully adjusted two-pollutant models in the highest compared with the lowest exposure quartile were 1.62 (95% CI = 1.02, 2.62) for NO _x and 1.47 (95% CI = 0.97, 2.25) for road traffic noise, with clear trends across exposure categories.
Conclusions: Our findings suggest that NO _x and road traffic noise are associated with an increased risk of PD. While the association with NO _x has been shown before, further investigation into the possible role of environmental noise on PD is warranted.
Competing Interests: The authors declare that they have no conflicts of interest with regard to the content of this report.
(Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The Environmental Epidemiology. All rights reserved.)