Dunedin, New Zealand: Cannabis exposure does not negatively impact the lungs in a manner consistent with tobacco, nor is it similarly linked to elevated rates of either COPD (chronic obstructive pulmonary disease) or lung cancer, according a literature review published in the journal Addiction.
A team of New Zealand researchers reviewed clinical trial data assessing the impact of cannabis smoke exposure on the lungs. They report that "the effects of smoking cannabis on the lungs are distinct from tobacco."
Specifically, they write: "[I]t has been pragmatic to assume that cannabis and tobacco would have similar respiratory effects. ... The research that has been done, however, offers a different story. The most common serious respiratory consequences from smoking tobacco are Chronic Obstructive Pulmonary Disease (COPD) and lung cancer. Epidemiological evidence that smoking cannabis causes either of these is scant."
By contrast, authors reported that cannabis smoke exposure is associated with higher rates of cough, sputum production, and chronic bronchitis.
They reported "little epidemiological evidence of an association between cannabis and emphysema," and found conflicting evidence with respect to whether marijuana smoke exposure is associated with an increased risk of pneumonia.
Full text of the study, "Cannabis use disorder and the lungs," appears in Addiction. Additional information is available in the NORML fact-sheet, 'Cannabis Exposure and Lung Health."