In this investigation, the authors reviewed a set of studies that explored the relationship between smoking marijuana and lung cancer. Specifically, investigators wanted to ascertain if marijuana smoking was related to either lung cancer risk factors or a greater prevalence of lung cancer. A search of several research databases yielded 19 studies that met criteria (e.g., individuals 18 years or older) to be included in a qualitative review of the relevant research.
- Some studies found higher levels of tar exposure and negative alveolar macrophage effects for marijuana smokers when compared to tobacco smokers.
- Several studies indicated increased metaplastic pathology and histopathologic and bronchial mucosal alterations for marijuana smokers as compared to those who smoked tobacco or did not smoke.
- Other studies reviewed did not find an association between marijuana smoking and lung cancer diagnoses.
- Methodological limitations observed in the studies reviewed included small samples, not controlling for tobacco use and selection bias.