The literature on air pollution and brain health is rapidly expanding and it is a universal finding that greater exposure to air pollution is associated with worse outcomes, whatever the measure of brain health used (clinical dementia, neuroimaging correlates, or cognitive impairment). However, there are a number of important questions which the studies currently published are not able to answer: when in the life course does exposure to air pollution most have the most impact?; which pollutant(s) or components are most important?; and since dementia describes a heterogeneous group of conditions, which is most affected by exposure to air pollution?
We briefly review and discuss the nine articles which have been published so far in 2018, so recently that they were not included in the four review articles also published this year. We highlight the variation in estimates of air pollution used but the consistency in deriving them from residential address (with or without some knowledge of an individual's previous home locations).
We are now at the stage when the research agenda needs to be agreed and we believe these three questions should be the focus of future research.
aAlzheimer Scotland Dementia Research Centre
bCentre for Cognitive Ageing & Cognitive Epidemiology
cCentre for Dementia Prevention
dDivision of Psychiatry, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh
eCentre for Ecology & Hydrology, Penicuik
fUniversity of Exeter Medical School, Truro
gCentre for Occupational and Environmental Health, University of Manchester, Manchester, UK
Correspondence to Dr Tom C. Russ, Alzheimer Scotland Dementia Research Centre, University of Edinburgh, 7 George Square, Edinburgh EH8 9JZ, UK. Tel: +44 0 131 650 4340; e-mail: T.C.Russ@ed.ac.uk