# Exposure to ambient air pollution and onset of Parkinson’s disease in a large cohort study

## TL;DR

A study in Northern Ireland found no overall link between air pollution and Parkinson's disease, but noted a possible connection in people under 50.

## Contribution

The study provides new insights into age-related differences in the potential link between air pollution and Parkinson’s disease.

## Key findings

- No overall association found between PM2.5 or NO2 exposure and Parkinson’s disease onset.
- A positive association was observed between PM2.5 exposure and PD onset in those under 50 in 2011.
- Weaker evidence suggested a link between NO2 exposure and PD onset in younger individuals.

## Abstract

This population-based longitudinal cohort study examines the association between ambient air pollution (PM2.5 and NO2) and Parkinson’s disease (PD) using a 28% representative sample of Northern Ireland’s population (2009–2016). We matched complete address records to annual average PM2.5 and NO2 concentrations at a 1 km grid level and tracked PD onset via first receipt of PD medication. After controlling for confounding factors at individual, household, and neighbourhood levels, we found no association between medium-term PM2.5 or NO2 exposure and PD onset in the overall cohort, over-50s, or sex-stratified samples. However, a positive association was observed between PM2.5 exposure and PD onset in those under 50 in 2011, with weaker evidence for NO2. We discuss potential etiological and non-etiological explanations for this age-related difference.