LOS ANGELES – The pulmonary consequences of regularly smoking marijuana are far less than for tobacco, according a review of the published evidence conducted by Dr. Donald P. Tashkin, emeritus professor of medicine and medical director of the pulmonary function laboratory at the University of California, Los Angeles.
Habitual use of marijuana alone doesn’t appear to lead to significant abnormalities in lung function, nor does it increase the risks of COPD or either lung or upper airway cancer. It is associated with an increase in symptoms of chronic bronchitis; however the symptoms go away upon discontinuation of use, according to Dr. Tashkin (Ann. Am. Thorac. Soc. 2013;10:239-47).
"The accumulated weight of evidence implies far lower risks for pulmonary complications of even regular heavy use of marijuana, compared with the grave pulmonary consequences of tobacco," he concluded.
In an accompanying editorial, Dr. Mark A. Ware called Dr. Tashkin’s article "the most comprehensive and authoritative review of the subject ever published."
Dr. Tashkin’s conclusion that smoking marijuana is not a major risk factor for airway cancer or COPD "will affect the way health professionals interact with patients, parents with teenagers, and policy makers with their constituents," predicted Dr. Ware, a family physician and anesthesiologist who is director of clinical research at the Alan Edwards Pain Management Unit at McGill University in Montreal.
Dr. Tashkin reported having no conflicts of interest. Dr. Ware has received lecture fees from the Canadian Consortium for the Investigation of the Cannabinoids and a research grant and honoraria from Valeant for conducting a randomized trial of nabilone in fibromyalgia patients.