On Traffic-Related Air Pollution and Noise, Mediating Associations Between Urban Design (including Greenness) and Mental Health. Evidence from the Barcelona Health Survey

S07: Of moderators and mediators: Complex relationships between greenness, air pollution, noise, and health behaviors in driving health outcomes, Beatrix Theater, August 27, 2019, 10:30 AM - 12:00 PM Background/Aim: The urban built environment and environmental exposures such as road traffic noise and ambient air pollution could affect mental health, but it's unclear how these factors interact. We aim to study these factors simultaneously to holistically evaluate the impact on mental health. Methods: This cross-sectional study is based on a population-based sample of 3362 individuals aged 15-97 years residing in Barcelona, Spain that participated in the Barcelona Health Survey 2016. A face-to-face interview was carried out by trained interviewers at the respondent's residence. We characterized the built environment (e.g. population density, facility richness, greenness), road traffic noise, and ambient air pollution at the residential level using a geographical information system (GIS). Mental health was assessed with the 12-item General Health Questionnaire. Results: Characteristics of the built environment, road traffic noise and air pollution were low-to-moderately correlated with each other. Adjusted mixed effects regression showed that higher facility richness was associated with a higher likelihood of poor mental health (odds ratio 1.01; 95%CI 1.00, 1.03), while residing in areas with higher slopes was associated with lower a likelihood of poor mental health (per interquartile range, OR 0.88; 0.81, 0.95). Odds ratios for greenness and poor mental health were <1 but were not statistically significant. Noise and air pollution indicators appeared to be associated with poor mental health, but this was only statistically significant for coarse particulate matter (per iqr, OR 1.27; 1.07, 1.51). Conclusion: Characteristics of the built environment and air pollution were associated with poor mental health. Further factor and mediation analysis will be carried out to shed light on interrelations between these factors and pathways to poor mental health.