What inhaled cannabis smoke does to the lungs

Cannabis smoking topography (deeper inhalation, longer breath-holding) results in higher per-puff exposures to tar and gases compared to tobacco. Chronic cough, sputum, wheeze, and airway inflammation are similar between cannabis and tobacco smokers. Cannabis smoke has modest bronchodilator properties but of unclear clinical significance. Alveolar macrophages from cannabis smokers show deficits in cytokine production and antimicrobial activity not seen in tobacco smokers.

Focused literature review examining respiratory symptoms, lung function, bronchial mucosa changes, alveolar macrophage function, COPD, lung cancer, and pulmonary infection risks.

With cannabis use increasing, understanding the respiratory profile of smoked cannabis helps inform harm reduction choices, particularly for people who also smoke tobacco.

The immune deficit finding in alveolar macrophages is particularly notable since it suggests a unique vulnerability to lung infections that is not present with tobacco smoking alone.

Relative paucity of well-controlled studies. Most research is confounded by concurrent tobacco use. Conflicting outcomes across studies prevent firm conclusions.