Long-term exposure to multiple air pollutants and risk of Parkinson's disease: A population-based multipollutant model study

Abstract

Background Recent evidence suggests brain-first Parkinson's disease (PD) may start from the olfactory system, indicating potential inhalational exposure to causal agents. We investigated the impact of long-term exposure to various air pollutants on PD incidence using both single- and multi-pollutant models to account for interactions between pollutants. Methods This retrospective population study used data from Taiwan's National Health Insurance Research Database (2006 and 2018) and included individuals aged 40-65 without PD. Personal exposure levels to various air pollutants, including PM 2.5, PM 10, NO 2, O 3, SO 2 and CO, were calculated using the hybrid Kriging/land-use regression method. Cox regression models were used to analyse the association between pollutants and PD incidence, adjusting for covariates. Results A total of 5 113 322 individuals without PD (mean age 50.1±6.9 years, 47.3% men) were followed for an average of 11.2±2.4 years, during which 20 694 incident cases of PD were identified. In the single-pollutant model, exposure to PM 2.5 (HR 2.65 (95% CI 2.59 to 2.72)), PM 10 (HR 3.13 (3.04 to 3.22)), NO 2 (HR 1.74 (1.68 to 1.80)) and SO 2 (HR 1.68 (1.65 to 1.71)) was associated with an increased risk of PD. These associations remained robust in the multipollutant model. A positive association between exposure to O 3 and an increased risk of PD (HR 1.29 (1.25-1.33)) was observed after adjusting for co-pollutants. Conclusions This nationwide cohort study employing multiple-pollutant models for considering the interaction effects revealed an association between exposure to multiple air pollutants and the risk of PD, emphasising the need for early prevention strategies.