Prominent role of PM10 in the link between air pollution and incident Parkinson's Disease

Abstract

Air pollution has been associated with Parkinson's Disease (PD) risk, although this relationship remains unclear. We estimated yearly levels of exposure to ten air pollutants (period 2006-2018) in an Italian population cohort, the Moli-sani study (N = 24,325; ≥35 years; 51.9% women), and derived three principal components, testing their associations with incident PD risk over 23,841 participants (213 cases, median(IQR) follow-up 11.2(2.0) years). This revealed a statistically significant association of PC1 (explaining 38.2% of common variance, tagging PM10 levels), independent on sociodemographic, professional and lifestyles covariates (Hazard Ratio [95%CI] = 1.04[1.02-1.07]). The association was confirmed testing average PM10 levels during follow-up (18[13-24]% increase of PD risk per 1 μg/m³ increase of PM10). Among different circulating markers, lipoprotein a explained a significant proportion of this association (2.8[0.9; 8.4]%). These findings suggest PM10 as a target to lower PD risk at the population level and a potential implication of lipoprotein a in PD etiology.

Fig. 1. Kaplan Meier curves of incident PD events vs PM10 quantiles.

Incident Parkinson’s disease events are compared between the two quantiles of exposure to PM10: below the median (11.65 μg/m³; green) and above the median (red).

Fig. 2. Geolocalization of participants and air pollutants maps in the Moli-sani cohort.

a Geographical location (based on residence address) of each participant to the Moli-sani cohort. b Example of air pollutant exposure map built in the study, based on Kriging algorithm (PM10, year 2007). Triangles represent land boxes used to build the map, whose data are publicly available from the regional environmental authority (Agenzia Regionale per la Protezione Ambientale del Molise - ARPA Molise, see URLs). Gradient colors represent increasing PM10 levels (μg/m³), from low (blue shades) to high (red shades).