Research on the relationship between air pollution and neurodegenerative diseases is growing. However, few studies focus on this association in contaminated sites. We investigated the association between long-term air pollution exposure and dementia/Parkinson's disease (PD) incidence in the River Sacco Valley, a contaminated site in central Italy. Through a retrospective cohort study, we enrolled 298,919 40+ years-old residents in 95 municipalities across the study area from 2007 to 2018. Residential exposure to benzene (C6H6), NO2, O3, PM10, PM2.5 and SO2 was estimated through FARM dispersion models with 1-4 km2 resolution. Risks were computed for interquartile range (IQR) increases of each pollutant. Incidence of dementia and PD was determined combining electronic health records. We used Cox proportional hazard regression with age as time axis and sex, socio-economic position (SEP) and municipality of residence as covariates. Study population was formed by 53 % females, 65 % 40-64 years old, 32 % medium-low SEP. Among 40+ years-old individuals, increased risks (HR; 95 % CIs) of dementia resulted from IQR increases of C6H6 (1.15; 1.11-1.18), NO2 (1.17; 1.14-1.21), PM10 (1.08; 1.04-1.11) and PM2.5 (1.10; 1.07-1.13). Increased risks of PD resulted from IQR increases of O3 (1.17; 1.14-1.21) and PM2.5 (1.02; 1.00-1.05). Vascular dementia's risk increases resulted from IQR increases of NO2 and PM2.5. Results for dementia and PD varied based on the pollutant analyzed. Our results concord with previous literature and the biological mechanisms that link air pollution to neurodegeneration. Air pollution might be a risk factor for dementia and PD.
Keywords: Air pollution; Alzheimer's; Cohort; Dementia; Neurodegeneration; Parkinson's.
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