A cohort study relating urban green space with mortality in Ontario, Canada

► Few studies, primarily ecological, have evaluated the relationship between green space and mortality. ► We studied associations between green space and death in a 22 year follow-up of 575,000 adults. ► Green space was assigned using the remote-sensing derived Normalized Difference Vegetation Index. ► Green space was inversely associated with mortality, particularly, for non-malignant respiratory disease. ► Additional research is needed to confirm these findings, and evaluate the potential role of self selection bias.