Cannabis use and risks of respiratory and all-cause morbidity and mortality: a population-based, data-linkage, cohort study

Abstract Introduction: Although cannabis is frequently used worldwide, its impact on respiratory health is characterised by controversy. Objective: To evaluate the association between cannabis use and respiratory-related emergency room (ER) visits and hospitalisations. Methods: A retrospective, population-based, cohort study was carried out, linking health survey and health administrative data for residents of Ontario, Canada, aged 12–65 years, between January 2009 and December 2015. Individuals self-reporting cannabis use within the past year were matched to control individuals (people who reported never