Marijuana and lung function

A paper is published in the European Respiratory Journal examining the effects of long-term marijuana smoking on lung function. Over 5,000 people were included in the study, whose lung functions were examined using spirometry. The intensity of marijuana smoking was defined on the basis of jointo-years. That is, one joint year means smoking one joint a day all year, or smoking 365 a year. People who were assigned a significant exposure to marijuana were defined as those who had smoked 20 jointo-years. This does not mean that they smoked marijuana for 20 years, but that the intensity of the drug use was as if they were smoking one joint every day for 20 years. In this group of people the risk of chronic obstructive pulmonary disease was almost 2.5 times higher than those who did not smoke marijuana or cigarettes. In this regard, lung function, as measured by forced expiratory first-second volume, decreased faster in marijuana smokers compared to those who did not smoke either cigarettes or marijuana. Lung function deteriorated most rapidly in those who smoked both marijuana and cigarettes. The results of this observational study indicate that, like cigarette smokers, heavy cannabis smokers may lose their lung function irreversibly, which may contribute to future deterioration and an increased risk of chronic obstructive pulmonary disease.