By Paul Armentano, NORML Deputy Director
Pulmonary complications associated with the regular smoking of cannabis are "relatively small" and far lower than those associated with tobacco smoking, according to a recent review published in the June edition of the scientific journal Annals of the American Thoracic Society.
The paper - authored by Donald P. Tashkin, MD, emeritus professor of medicine and medical director of the Pulmonary Function Laboratory at the David Geffen School of Medicine at University of California, Los Angeles - is "the most comprehensive and authoritative review of the subject ever published," according to an accompanying commentary. Donald Tashkin conducted US-government sponsored studies of marijuana and lung function for over 30 years.
His review finds that although smoking cannabis may be associated with symptoms of chronic bronchitis, studies do not substantiate claims that it is positively associated with the development of lung cancer, chronic obstructive pulmonary disease (COPD), emphysema, or bullous lung disease.
"[H]abitual use of marijuana alone does not appear to lead to significant abnormalities in lung function," Tashkin writes. "[F]indings from a limited number of well-designed epidemiological studies do not suggest an increased risk of either lung or upper airway cancer from light or moderate use. ... Overall, the risks of pulmonary complications of regular use of marijuana appear to be relatively small and far lower than those of tobacco smoking."
Writing in an accompanying commentary, McGill University's Dr. Mark Ware concludes: "Cannabis smoking is not equivalent to tobacco smoking in terms of respiratory risk. ... [C]annabis smoking does not seem to increase risk of chronic obstructive pulmonary disease (COPD) or airway cancers. In fact, there is even a suggestion that at low doses cannabis may be protective for both conditions. ... This conclusion will affect the way health professionals interact with patients, parents with teenagers, and policy makers with their constituents. ... Efforts to develop cleaner cannabinoid delivery systems can and should continue, but at least for now, [those] who smoke small amounts of cannabis for medical or recreational purposes can breathe a little bit easier."
Full text of the study, "Effects of marijuana smoking on the lung," appears in Annals of the American Thoracic Society.