Cannabis Use Disorder and Mortality Risk: A Matched Cohort Study from a Colorado Health System.

Nguyen A.; Narwaney K.; Lyons J.; Ford M.; Steiner C. · Journal of general internal medicine · 2026

**Background & Methods** This matched cohort study analyzed 100,140 individuals (16,693 with cannabis use disorder [CUD] and 83,447 without CUD) from a Colorado health system between 2006-2024, with follow-up through June 2024. The study compared all-cause and cause-specific mortality rates between groups using Cox proportional hazards regression to calculate adjusted hazard ratios. **Key Findings** • Individuals with CUD experienced significantly elevated all-cause mortality (899.5 vs. 374.6 per 100,000 person-years; adjusted HR 1.52, 95% CI 1.30-1.77) compared to matched controls over a median 7.7-year follow-up period, with 1,197 deaths (7.2%) occurring in the CUD cohort. • CUD was associated with substantially increased injury-related mortality (295.3 vs. 62.5 per 100,000 person-years; HR 1.91, 95% CI 1.37-2.67), with drug overdose mortality showing the strongest association (HR 2.59, 95% CI 1.30-5.19), followed by accidents (HR 1.96, 95% CI 1.01-3.80). • Illness-related mortality was also elevated in the CUD group (604.2 vs. 312.1 per 100,000 person-years; HR 1.40, 95% CI 1.17-1.67), with cancer demonstrating a significant association (HR 1.71, 95% CI 1.20-2.46), though cardiovascular and respiratory disease mortality showed no statistically significant increase. **Dosage & Administration** Not reported. **Safety & Adverse Effects** Not reported. The study examined mortality outcomes rather than direct adverse effects of cannabis use. **Evidence Quality** This matched cohort study provides moderate-to-good evidence but has notable limitations. The population is restricted to a single Colorado health system, potentially limiting generalizability to other geographic regions and healthcare systems. The study is observational, precluding causal inference; CUD may serve as a marker for unmeasured confounding factors (socioeconomic status, mental health comorbidities, substance polyuse) rather than a direct cause of mortality. The broad age range (≥12 years) and extended follow-up period strengthen internal validity, though specific adjustment variables and potential residual confounding are not fully detailed. The lack of significant associations for self-harm, cardiovascular, and respiratory diseases may reflect insufficient statistical power for these outcomes.

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