Nicholas T. Vozoris, Jingqin Zhu, Clodagh M. Ryan, Chung-Wai Chow, Teresa To

Although cannabis is frequently used worldwide, its impact on respiratory health is characterised by controversy.

… 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.

… Although no significant association was observed between cannabis use and respiratory-related ER visits or hospitalisations, the risk of an equally important morbidity outcome, all-cause ER visit or hospitalisation, was significantly greater among cannabis users than among control individuals. Therefore, cannabis use is associated with increased risk for serious adverse health events and its recreational consumption is not benign.