Cannabis use and its impact on respiratory physiology and lung cancer risk: Mechanistic and epidemiological insights (Review).

Cannabis use has become increasingly prevalent due to legalization and social acceptance, raising concerns about its potential health impacts, particularly on respiratory and oncological outcomes. Despite sharing toxic constituents with tobacco smoke, including polycyclic aromatic hydrocarbons and volatile organic compounds, the link between cannabis smoking and lung cancer remains inconclusive. Epidemiological studies present conflicting findings, with some suggesting increased risk among heavy users, particularly when combined with tobacco, while others find no significant association. Chronic cannabis smoking has been associated with respiratory symptoms such as cough, sputum production and wheezing, often resembling chronic bronchitis. These symptoms may resolve upon cessation, indicating inflammatory rather than structural damage. Unlike tobacco, cannabis smoking does not consistently induce emphysema but may cause airflow obstruction and increased lung volumes with heavy and prolonged use. Additionally, cannabis smoking impairs alveolar macrophage function, diminishing antimicrobial capabilities and potentially increasing susceptibility to respiratory infections. While cannabinoids such as Δ