SummaryAir pollution can harm human health in many ways, including harmful effects on olfactory and brain health. Air pollution can damage olfactory functioning via inflammation within the olfactory bulb and can trigger inflammatory responses and neuronal damage in the brain, contributing to cognitive impairment. The combination of these effects can be observed in our ability to identify and recall known, previously experienced smells, which relies on both executive and semantic memory, involving both the olfactory system and cognitive processes. Our proposal aims to investigate the association between key ambient air pollutants and odor identification within the German National Cohort (NAKO) using longitudinal data. Using repeated assessments of odor identification, we will assess if and how air pollution exposure influences changes in odor identification over time. To achieve this, we will use detailed long-term data on key ambient air pollutants, including particulate matter with an aerodynamic diameter of 2.5 µm or less (PM2.5), black carbon, particulate matter with an aerodynamic diameter of 10 µm or less (PM10), particulate matter with aerodynamic diameter between 2.5 µm and 10 µm (PMcoarse¬), particle number concentration (PNC) which is a common proxy measurement for ultrafine particles (UFP), and nitrogen dioxide (NO2). This data has been assigned to each participant where available based on their baseline residential addresses by the environmental data unit (EDU). We will implement a longitudinal analysis using generalized linear mixed models with a logit link to assess the odds of developing poor odor identification over time associated with long-term air pollution exposure, and linear mixed-effects models to assess the association between long-term air pollution exposure and reductions in odor identification score over time. We aim to provide robust evidence of the effects of long-term air pollution exposure on odor identification, providing new insights into the pathway between air pollution exposure and cognitive decline.

Keywords Longitudinal air-pollution cognition long-term-exposure odor-identification

InstitutionsHelmholtz Munich, Helmholtz Zentrum München, Universitätsmedizin Greifswald, Institut für Epidemiologie der Universität Münster, Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt, IUF - Leibniz Institut für umweltmedizinische Forschung, Universitätsmedizin Greifswald, Institut für Community Medicine, Abtlg. SHIP-KEF