Cannabis use was not linked to respiratory ER visits but was associated with more overall hospitalizations
In a population-based study of over 35,000 Ontarians, past-year cannabis use was not associated with respiratory ER visits or hospitalizations, but was associated with 22% higher odds of all-cause ER visits.
Quick Facts
What This Study Found
No significant difference in respiratory-related ER visits/hospitalizations between cannabis users and controls (OR 0.91, 95% CI 0.77-1.09). Cannabis users had significantly higher odds of all-cause ER visits/hospitalizations (OR 1.22, 95% CI 1.13-1.31). No difference in all-cause mortality (OR 0.99).
Key Numbers
35,114 individuals screened. 6,425 past-year cannabis users. 4,807 matched to 10,395 controls. Respiratory ER/hospitalizations: OR 0.91 (not significant). All-cause ER/hospitalizations: OR 1.22 (significant). All-cause mortality: OR 0.99 (not significant).
How They Did This
Retrospective population-based cohort study linking health survey and administrative data for Ontario, Canada residents aged 12-65 (2009-2015). 6,425 past-year cannabis users propensity-score matched to 10,395 controls on 31 variables. Outcomes assessed at 12 months.
Why This Research Matters
This well-designed, population-based study adds to the evidence that cannabis does not significantly increase respiratory-specific health emergencies, while confirming it is associated with increased overall healthcare utilization.
The Bigger Picture
The disconnect between the null respiratory finding and the significant all-cause finding suggests cannabis-related health risks may manifest through non-respiratory pathways, including accidents, mental health crises, or cardiovascular events.
What This Study Doesn't Tell Us
Self-reported cannabis use may be underreported. 12-month follow-up may miss longer-term effects. Propensity matching cannot eliminate all confounders. Administrative coding may miss some cannabis-related visits.
Questions This Raises
- ?What types of all-cause ER visits are driving the increased utilization?
- ?Would longer follow-up reveal respiratory effects?
- ?Does consumption method (smoking vs other) matter for respiratory outcomes?
Trust & Context
- Key Stat:
- No respiratory ER increase, but 22% higher all-cause ER visits
- Evidence Grade:
- Strong: large population-based cohort with propensity-score matching on 31 variables and administrative outcome data.
- Study Age:
- Published in 2022.
- Original Title:
- Cannabis use and risks of respiratory and all-cause morbidity and mortality: a population-based, data-linkage, cohort study.
- Published In:
- BMJ open respiratory research, 9(1) (2022)
- Database ID:
- RTHC-04282
Evidence Hierarchy
Looks back at existing records to find patterns.
What do these levels mean? →Frequently Asked Questions
Does cannabis cause lung problems?
In this study, past-year cannabis use was not associated with respiratory-related ER visits or hospitalizations, consistent with other evidence that cannabis may not cause the same respiratory emergencies as tobacco.
Why were all-cause ER visits higher?
The study did not break down the types of all-cause visits. Potential contributors include accidents, injuries, mental health events, and cardiovascular events, but this requires further investigation.
Is recreational cannabis use benign?
The authors conclude it is not. While respiratory-specific risks were not elevated, the 22% increase in all-cause ER visits and hospitalizations represents a meaningful health burden.
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Cite This Study
https://rethinkthc.com/research/RTHC-04282APA
Vozoris, Nicholas T; Zhu, Jingqin; Ryan, Clodagh M; Chow, Chung-Wai; To, Teresa. (2022). Cannabis use and risks of respiratory and all-cause morbidity and mortality: a population-based, data-linkage, cohort study.. BMJ open respiratory research, 9(1). https://doi.org/10.1136/bmjresp-2022-001216
MLA
Vozoris, Nicholas T, et al. "Cannabis use and risks of respiratory and all-cause morbidity and mortality: a population-based, data-linkage, cohort study.." BMJ open respiratory research, 2022. https://doi.org/10.1136/bmjresp-2022-001216
RethinkTHC
RethinkTHC Research Database. "Cannabis use and risks of respiratory and all-cause morbidit..." RTHC-04282. Retrieved from https://rethinkthc.com/research/vozoris-2022-cannabis-use-and-risks
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.