Long-term air pollution exposure and mortality due to dementia, Parkinson’s Disease and psychiatric disorders: the ELAPSE project

BACKGROUND AND AIM: Ambient air pollution exposure has been linked to neurodegenerative and psychiatric disorders, but evidence remains limited. We examined the association between long-term air pollution exposure and mortality due to dementia, Alzheimer’s Disease (AD), Parkinson’s Disease (PD), psychiatric disorders and suicides in a pooled analysis of eight European cohorts. METHODS: Within the project ‘Effects of Low-Level Air Pollution: A Study in Europe’ (ELAPSE), we pooled data from eight cohorts from six European countries. Annual mean residential concentrations in 2010 for fine particulate matter (PM2.5), nitrogen dioxide (NO2), black carbon (BC) and ozone (O3) were estimated using Europe-wide hybrid land use regression models. We applied stratified Cox proportional hazard models, adjusting for potential confounders, to investigate the associations between air pollution and mortality due to dementia, AD, PD, psychiatric disorders, and suicides. RESULTS:Of 325,367 participants, 1167 died from dementia (528 from AD), 468 from PD, 995 from psychiatric disorders, and 273 from suicides, during a mean follow-up of 19.5 years. We observed positive associations of NO2, PM2.5 and BC with PD (hazard ratio; 95% confidence intervals: 1.14; 0.98-1.33 per 10 µg/m3 in NO2, 1.26; 1.03-1.55 per 5 µg/m3 in PM2.5, and 1.09; 0.93-1.27 per 5 10-5m-1 in BC), psychiatric disorders (1.08; 0.98-1.19; 1.21; 1.02-1.43; 1.12; 1.01-1.24) and suicides (1.16; 0.98-1.37; 1.14; 0.79-1.65; 1-10; 0.93-1.31). We found weak negative associations of NO2, PM2.5 and BC with dementia (0.92; 0.84-1.00; 0.92; 0.79-1.07; 0.91; 0.83-1.00) or AD (0.93; 0.82-1.06; 0.85; 0.69-1.03; 0.89; 0.78-1.03). CONCLUSIONS:Long-term exposures to NO2, PM2.5 and BC may be associated with premature mortality from PD, psychiatric diseases and suicides. KEYWORDS: air pollution, dementia, Alzheimer's Disease, Parkinson's Disease, pyshiatric disorders, suicide