Association Between Long-Term Exposure to Air Pollution and Parkinson's Disease: Administrative Cohort of Older Adults in South Korea.
TL;DR
Long-term exposure to PM2.5 and O3 was associated with a small but statistically significant increase in PD incidence among older adults in Korea, consistent with a possible association between air pollution and the etiology of neurodegenerative diseases, although effect sizes were modest.
Abstract
Background
Evidence regarding the association between long-term exposure to ambient air pollution and Parkinson's disease (PD) remains inconsistent, particularly among older adults in Asian populations.
Objective
We aimed to examine the association between long-term exposure to ambient air pollutants and incident PD in a nationwide administrative cohort of older adults in South Korea.
Methods
We analyzed 5.3 million adults aged ≥65 years from the Korean National Health Insurance Database (2010-2019). Incident PD was ascertained using nationwide insurance claims data, requiring hospitalization or repeated outpatient diagnoses. District-level annual concentrations of fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3) were estimated using the Community Multiscale Air Quality model. Time-varying Cox proportional hazards models were used to estimate hazard ratios (HRs) per interquartile range (IQR) increase in a 1-year moving-average exposure, adjusting for individual- and district-level covariates.
Results
During follow-up, 143,557 PD cases were identified. In fully adjusted models, each IQR increase in PM2.5 (4.3 μg/m3) and O3 (7.3 ppb) was associated with a modestly increased PD incidence (PM2.5: HR = 1.018, 95% CI: 1.008-1.028; O3: HR = 1.019, 95% CI: 1.006-1.033). However, NO2 showed an inverse association after full adjustment. Effect modification by demographic or clinical characteristics was not statistically significant.
Conclusions
Long-term exposure to PM2.5 and O3 was associated with a small but statistically significant increase in PD incidence among older adults in Korea. These findings are consistent with a possible association between air pollution and the etiology of neurodegenerative diseases, although effect sizes were modest and should be interpreted with caution. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.