Marijuana and Lung Disease.
Level 5 - mechanism / opinion, no new human data
Narrative review without systematic search or meta-analytic methodology
PubMed 29778658 · doi:10.1016/j.chest.2018.05.005
What was done
This narrative review synthesized clinical, physiological, radiological, and epidemiological literature evaluating the pulmonary effects of marijuana smoking. Outcomes addressed from the cited studies included symptoms of chronic bronchitis, pulmonary function indices (FEV1, FVC, FEV1/FVC ratio, specific airway conductance, diffusing capacity), thoracic high-resolution CT findings of emphysema, bronchial histopathology, lung cancer risk (citing a large cohort study and a pooled analysis of six case-control studies), pneumonia, and case series reporting bullous lung disease or pneumothorax/pneumomediastinum.
What was found
The abstract reports no numerical data. Qualitatively, marijuana smoking is consistently associated with chronic bronchitis symptoms after adjusting for tobacco, as well as precancerous histopathologic changes in bronchial biopsies, bronchial mucosal edema, and modest reductions in specific airway conductance. In contrast, studies found no relationship with FEV1 decrements, normal diffusing capacity, and rarely a decreased FEV1/FVC ratio (possibly attributable to increased FVC). Two high-resolution CT studies found no association with emphysema, and a large cohort study plus a pooled analysis of six case-control studies found no link to lung cancer. Pneumonia risks remain unconfirmed, and bullous disease or pneumothoraces are documented only in case series.
Why it matters
This synthesis helps delineate the pulmonary risks specific to marijuana smoking, showing clear associations with airway inflammation and bronchitis symptoms but a lack of evidence linking it to obstructive lung damage, emphysema, or lung malignancy.
Limits
The abstract describes a narrative review without systematic search criteria, quality appraisal, or meta-analytic pooling. Most underlying data stem from observational studies subject to confounding by tobacco use, and associations with pneumonia, bullous lung disease, and barotrauma lack controlled epidemiological validation. No sample sizes or exposure quantifications are reported.
Cited by
- supports A 25-year study by Dr. Donald Tashkin at UCLA found heavy daily cannabis smokers had a slight increase in lung capacity and no increased cancer incidence compared to non-smokers.