Impact of Marijuana Smoking on Lung Health

This chapter reviews the literature pertaining to the concern that regular smoking of marijuana contributes to the well-known respiratory consequences of regular tobacco smoking, including, chronic obstructive pulmonary disease (COPD) and respiratory cancer. Whereas regular marijuana smoking is associated with symptoms of acute and chronic bronchitis and evidence of microscopic injury to the cells lining the central airways, the majority of community- or population-based studies in regular smokers of marijuana have not found evidence of clinically significant impairment in lung function in comparison with nonsmokers that would be consistent with COPD. However, very few studies have been conducted in older marijuana smokers in the age range when COPD is generally diagnosed, and few longitudinal studies of change in lung function over time have been carried out in smokers of marijuana. Therefore, firm conclusions regarding the potential risks of marijuana for the development of COPD must await additional studies.