There are opinions on both sides of the fence in the debate about whether cannabis smoke is as harmful to human lung function as cigarette smoke. Unfortunately, there is little scientific research to back up either argument because research teams experience difficulty obtaining permission to study any substance classified as a Schedule I in the United States, which is how cannabis is scheduled.
Findings from the newest research studying the long-term effects of cannabis use on lung function were recently published in the Annals of the American Thoracic Society. The cross-sectional study concluded that smoking up to one cannabis joint per day for twenty years does not adversely effect a person’s ability to exhale at the appropriate lung strength. The study authors summarized the research with the sentence, “lifetime marijuana use up to 20 joint-years is not associated with adverse changes in spirometric (measuring of breath strength and lung function) measures of lung health.”
This study is titled “Effects of Marijuana Exposure on Expiratory Airflow: A Study of Adults who Participated in the U.S. National Health and Nutrition Examination Study,” and was conducted by the research team at Emory University in Atlanta, GA. These results were determined by using the data and survey questions from participants in the 2007-2008 and 2009-2010 National Health and Nutrition Examination Survey.
A similar study published in 2012, which followed 5,000 adults in four U.S. cities for over twenty years, determined that long-term cannabis use does not deteriorate breathing or lung function. The lung function of most of the cannabis-using participants actually increased over the course of the twenty year study. This one also determined that twenty years of smoking cigarettes does result in a decrease in lung function.
A different study, also published in 2012, concluded that “whether marijuana smoke has similar adverse effects on pulmonary function [as tobacco smoke] is unclear. More specifically, it determined that “occasional and low cumulative marijuana use was not associated with adverse effects on pulmonary function.” However, this one concluded that it is possible that chronic use may potentially cause “airway mucosal injury and inflammation.”
Although, according to these studies, cannabis smoking may not be linked to deteriorated lung function in humans, vaporizing is still a healthier alternative to smoking. With vaporizing, the plant never reaches the point of combustion, which thereby reduces the absorption of toxic byproducts into the lungs. Learn more about different options for use and methods of delivery here.
Consideration should also be given to the quality of the product being smoked. If the cannabis being used has been treated with many pesticides or other harmful chemicals during the growing and curing process, chances of lung damage may increase.
More research is needed to be certain of the health effects of long-term cannabis use. Scientists have limited access to study marijuana because of it’s current classification of a Schedule I drug in the United States under the Controlled Substances Act of 1970. That classification means that marijuana has no medicinal uses, therefore scientists cannot easily obtain permission to study the plant. Once cannabis is re-scheduled, or most appropriately unscheduled, scientists will be able to conduct more research and clinical trials to better understand this fascinating plant.