Long-Term Exposure To Air Pollution And Traffic Noise And Global Cognitive Score – Results From The Heinz Nixdorf-Recall Study

Introduction: Investigations of adverse effects of air pollution (AP) and ambient noise on cogni-tive function are scarce, and their results are inconsistent. The aim of this study was to analyze the associations of long-term exposure to AP and traffic noise with a global cognitive score (GCS) in single and two-exposure models. Data: Our analysis is based on cross-sectional data from the first follow-up examination (2006-2008) of the population-based Heinz Nixdorf Recall study, located in three adjacent in the highly urbanized German Ruhr Area. Methods: Cognitive performance was completed in 4086 of 4157 participants using five subtests: verbal fluency, labyrinth test, immediate and delayed verbal recall, and clock-drawing tests. The GCS was additively calculated using age- and education-specific z scores of the five subtests. We assessed long-term residential concentrations for size-specific particulate matter (PM) and nitrogen oxides with land use regression and dispersion models, and traffic noise (weighted 24-h (LDEN) and night-time (LNIGHT) means) according to the EU directive 2002/49/EC. Multiple linear regression models adjusted for individual risk factors (age, sex, socio-economic status, alcohol consumption, smoking status, self-reported passive smoking, any regular physical activity, and body mass index) were calculated for the association of environmental exposures with GCS. Results: In the fully adjusted model, AP and noise were negatively associated with GCS. For example, an interquartile range (IQR) increase in PM2.5 (1.43 µg/m3) was associated with a de-crease in GCS of β =-0.05 [95% confidence interval (CI) -0.0.8;-0.03] and for a 10 dB(A) increase in LDEN, β was -0.07 [-0.13; -0.01]). In two-exposure models, the estimates remained stable and significant for AP, but slightly attenuated for noise. Discussion: Long-term exposures to AP and road traffic noise were adversely associated with GCS in one- and two exposure models.