The effect of air pollution on cognitive functioning and the role of genetic variation

The relation between exposure to air pollution and dementia-related outcomes, such as cognitive functioning, is an active area of research. There is evidence of an effect of short-term and long-term air pollution exposure on cognition. The possible routes of air pollution to cognitive decline are not fully understood yet. One possibility is that air pollution can directly impact brain functioning. However, there could also be indirect pathways. Fine particulate matter could affect respiratory functioning which indirectly causes deteriorating cognitive performance in the future. Aretz et al. show in their paper "Long-Term Exposure to Fine Particulate Matter, Lung Function and Cognitive Performance: A Prospective Dutch Cohort Study on the Underlying Routes" that air pollution affects cognition both directly and indirectly via the lungs, where the direct way explains the largest part.

Genetic susceptibility for COPD, lung function and depression might play a role in the effect of exposure to air pollution on cognitive impairment. The proposed project aims to explore whether this genetic variation exacerbates or alleviates the effect of pollution on cognitive functioning. We propose to build a gene-environment interaction analysis on the analyses reported in the paper by Aretz et al. In that paper, the effect of exposure to air pollution on dementia is decomposed into two channels: one directly by way of the olfactory nerve and one indirectly through the lungs. It turns out that the first channel prevails. However, there may be subgroups of genetically predisposed individuals for whom the channel by way of the lung function is more important than on average in the population.