Systematic review confirms marijuana smoking harms the respiratory system | Research

The takeaway

A systematic review found marijuana smoking associated with multiple respiratory complications including chronic bronchitis symptoms, airway inflammation, and possible links to pneumonia and lung hyperinflation.

Pulmonologists, cannabis users who smoke, harm reduction advocates, and primary care providers.

Marijuana combustion produces respiratory irritants similar to tobacco smoke

What the researchers found

Marijuana smoking exposes lungs to combustion byproducts that cause airway inflammation, chronic bronchitis symptoms, and possible emphysematous changes. Evidence for associations with asthma, COPD, and pneumonia was also identified.

Why it matters

As marijuana legalization increases use, understanding respiratory risks is critical. The perception that marijuana smoke is less harmful than tobacco smoke persists despite evidence of significant respiratory irritation.

The numbers in context

Review covered respiratory outcomes including asthma, pneumonia, emphysema, COPD, and chronic bronchitis. Marijuana combustion produces harmful byproducts similar to tobacco smoke.

How the study worked

Systematic review of published literature on respiratory effects of marijuana smoking. Examined outcomes including airway inflammation, bronchitis, asthma, COPD, emphysema, pneumonia, and lung function changes.

What this study cannot tell us

Many included studies did not adequately control for concurrent tobacco use. Varying definitions of marijuana use frequency across studies. Limited long-term data. Does not address non-smoked cannabis routes.

How to read the evidence

Systematic review of observational studies. Moderate evidence quality limited by tobacco co-use confounding and heterogeneous study designs.

When this study was published

Published 2023.

The bigger picture

The respiratory effects of cannabis have been studied less than tobacco, but combustion chemistry suggests similar airway irritant exposure. The shift toward vaping and edibles may change the risk profile, but smoked cannabis remains the most common consumption method.

Questions still open

How do vaporized cannabis and smoked cannabis compare in respiratory effects? Does the frequency and amount of marijuana smoking determine a dose-response relationship with lung damage?

Common questions

Is smoking marijuana bad for your lungs?

Yes. This systematic review found marijuana smoking associated with chronic bronchitis symptoms, airway inflammation, and possible links to pneumonia and emphysema. Burning any plant material produces harmful byproducts, and marijuana combustion shares many irritants with tobacco smoke.

Is vaping cannabis safer for the lungs than smoking it?

This review focused on smoked cannabis and did not directly compare routes. Vaporizing heats cannabis below combustion temperature, theoretically producing fewer harmful byproducts. However, vaping carries its own risks (including EVALI outbreaks linked to vitamin E acetate in illicit products), and long-term vaping safety data is limited.

Read the original research

Effects of Smoking Marijuana on the Respiratory System: A Systematic Review.

Substance abuse, 44(3), 249-260

View on PubMed ↗Publisher’s paper ↗

Citation

Vásconez-González, Jorge; Delgado-Moreira, Karen; López-Molina, Belén; Izquierdo-Condoy, Juan S; Gámez-Rivera, Esteban; Ortiz-Prado, Esteban. (2023). Effects of Smoking Marijuana on the Respiratory System: A Systematic Review.. Substance abuse, 44(3), 249-260. https://doi.org/10.1177/08897077231186228