Traffic-Related Air Pollution and Parkinson’s Disease in Denmark: A Case–Control Study

Abstract

BackgroundVery little is currently known about air pollutants’ adverse effects on neurodegenerative diseases even though recent studies have linked particulate exposures to brain pathologies associated with Parkinson’s and Alzheimer’s disease.ObjectiveIn the present study, we investigated long-term exposure to traffic-related air pollution and Parkinson’s disease.MethodsIn a case–control study of 1,696 Parkinson’s disease (PD) patients identified from Danish hospital registries and diagnosed 1996–2009 and 1,800 population controls matched by sex and year of birth, we assessed long-term traffic-related air pollutant exposures (represented by nitrogen dioxide; NO2) from a dispersion model, using residential addresses from 1971 to the date of diagnosis or first cardinal symptom for cases and the corresponding index date for their matched controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated with logistic regression, adjusting for matching factors and potential confounders.ResultsWe found ambient air pollution from traffic sources to be associated with risk of PD, with a 9% higher risk (95% CI: 3, 16.0%) per interquartile range increase (2.97 μg/m3) in modeled NO2. For participants living for ≥ 20 years in the capital city, ORs were larger (OR = 1.21; 95% CI: 1.11, 1.31) than in provincial towns (OR = 1.10; 95% CI: 0.97, 1.26), whereas there was no association among rural residents.ConclusionsOur findings raise concerns about potential effects of air pollution from traffic and other sources on the risk of PD, particularly in populations with high or increasing exposures.CitationRitz B, Lee PC, Hansen J, Funch Lassen C, Ketzel M, Sørensen M, Raaschou-Nielsen O. 2016. Traffic-related air pollution and Parkinson’s disease in Denmark: a case–control study. Environ Health Perspect 124:351–356; http://dx.doi.org/10.1289/ehp.1409313

A joint ERS/ATS policy statement: what constitutes an adverse health effect of air pollution? An analytical framework

“…An increased rate of decline in cognitive function may also be associated with higher air pollution exposures [136]. Some studies have reported associations between exposure to air pollutants and dementia [137, 138], but not all study results support such a relationship [139]. …”

Ambient Air Pollution Exposures and Risk of Parkinson Disease

“…Few epidemiologic studies have examined the potential roles of ambient air pollutants in PD, and findings are inconsistent (Finkelstein and Jerrett 2007; Kirrane et al 2015; Palacios et al 2014a, 2014b; Ritz et al 2016; Willis et al 2010). Therefore, we investigated the association between ambient PM 10 , PM 2.5 , and nitrogen dioxide (NO 2 ) exposures and risk of PD in the Parkinson’s, Genes and Environment (PAGE) study.…”

Air pollution and Parkinson’s disease – evidence and future directions

“…In a nationwide case-control study in Denmark, Ritz et al (39) examined the associations between traffic-related air pollution (represented by NO 2 ) and PD. These authors analyzed exposures to NO 2 , NO x and CO but focused the analysis on NO 2 because of the high inter-correlation between the pollutants and NO 2 being a commonly studied air pollutant.…”

“…Few of the studies included in this review stratified their analyses by gender or smoking [e.g. Finkelstein and and Jerrett (40), Ritz et al (39), and Palacios et al (35,36,42) stratified by smoking]. In future studies, it would be important to examine the potential interactions between pollutant exposure and gender, smoking, as well as other exposures, such as antioxidants, caffeine, use of NSAID, and other factors.…”