No Decline in Pulmonary Function with Marijuana Use

The known associations between tobacco use and respiratory symptoms, chronic obstructive pulmonary disease, and lung cancer have been assumed to apply to smoking marijuana as well, but prior studies have shown only mucosal damage with no effect on actual pulmonary function. This secondary analysis of a multisite, prospective cohort study of coronary artery disease risk factors provided multiple assessments of tobacco and marijuana smoking and pulmonary function during 20 years in >5000 adults.

In adjusted analyses, there was a clear decrement in forced vital capacity (FVC) and forced expiratory volume at 1 second (FEV₁) with current and lifetime exposure to tobacco smoking, but no such decrement with exposure to marijuana smoking. In fact, s…