Urban exposome and stroke incidence across Europe

Background and Aim: Multiple environmental factors of urban environments may influence cardiovascular health, however their complex interplay has scarcely been studied. Within the EXPANSE project, we evaluated the association between multiple urban exposures and stroke incidence across Europe. Methods: We will conduct a meta-analysis including 3 population-based cohorts (from Sweden, Netherlands, Germany) and 6 administrative cohorts (from Greece, Rome, Catalonia, Switzerland, Sweden, Netherlands). Participants were followed-up until incident stroke, death, migration, disappearance or end of study period. We estimated multiple long-term exposures at residential addresses from different domains: ambient air pollution (nitrogen dioxide, particulate matter <2.5m, black carbon, ozone), built environment (green and blue spaces, impervious surface) and meteorology (mean and standard deviation temperatures during summer and winter). Associations between environmental exposures and incident stroke were estimated in single and multiple-exposure Cox proportional hazard models, and Principal Component Analyses (PCA) derived prototypes for exposures domain (i.e built environment). Results: Preliminary results from Sweden (N=19,247), from single and multiple exposures, indicate associations between increased levels of NDVI and reduced incident stroke (hazard ratio (HR) per 0.1 units = 0.92, 95%CI 0.85; 0.99). The first component of each domain in the PCA explained more than 60% of the variability. The built environment domain (capturing high levels of green spaces and low levels of impervious surface) showed a borderline association with incident stroke (HR per interquartile range of the component = 0.92, 95%CI 0.83; 1.01). We also found a suggestive association between air pollution and increased stroke incidence. Conclusions: In preliminary results in Sweden, we found a suggestion for independent effects of green space and air pollution on incident stroke. Further analyses on the other cohorts are ongoing. Keywords: stroke, urban exposome, meta-analysis, air pollution, green space, temperature, blue space.