Washington, DC: Recent media reports alleging that the daily use of cannabis may impede certain lung functions should be seen as an opportunity to better educate marijuana consumers about ways to mitigate the health risks associated with smoking, NORML Senior Policy Analyst Paul Armentano said today.
The widely reported study, published online in the journal Thorax, found that the daily long-term smoking of cannabis cigarettes obstructed airflow to the lungs in a manner equivalent to smoking 2.5 to 5 tobacco cigarettes in succession. Investigators hypothesized that this result was because some marijuana smokers may consume greater quantities of both tar and carcinogenic hydrocarbons than do those who inhale filtered tobacco cigarettes.
Heavy use of cannabis was also associated with wheezing, cough, and chest tightness, researchers found. However, investigators did not find a positive association between smoking cannabis and the development of emphysema (over-inflation of the air sacs in the lungs). Emphysema is the most common cause of death from respiratory disease in the United States.
Armentano said that cannabis consumers have long been aware that smoking marijuana cigarettes can irritate the lungs, but added that most of pot’s potential health risks to the respiratory system may be eliminated by vaporization. “By heating marijuana to a temperature where active cannabis vapors form, but below the point of combustion, consumers significantly reduce their intake of gaseous combustion toxins, including carbon monoxide,” he said.
Most recently, investigators at San Francisco General Hospital reported in the journal Clinical Pharmacology & Therapeutics that the “vaporization of marijuana does not result in exposure to combustion gases, … and is preferred by most subjects compared to marijuana cigarette.” A previous clinical trial published in 2006 in the Journal of Pharmaceutical Sciences reported that vaporization is “safe and effective” cannabinoid delivery system that “avoid[s] the respiratory disadvantages of smoking.”
Armentano also affirmed that cannabis smoking is not positively associated with cancers of the lung, mouth, or upper aerodigestive tract (e.g., pharynx, larynx, or esophagus). In 2006, the results of the largest case-controlled study ever to investigate the respiratory effects of marijuana smoking reported that pot use was not associated with cancer, even among subjects who reported smoking more than 22,000 joints over their lifetime.
“While smoking cannabis may pose some minor respiratory risks to the user, these health risks are far less than those posed by tobacco smoking and may be significantly mitigated by engaging in vaporization as an alternative to smoking,” Armentano concluded. “Unfortunately, cannabis prohibition greatly limits consumers access to such devices and impedes technological advancements in this area – subjecting users to respiratory risks that they would otherwise avoid.”
For more information, please contact Paul Armentano, NORML Senior Policy Analyst, at: paul@norml.org. Additional information is available in the NORML White Paper, “Cannabis Smoke and Cancer: Assessing the Risk,” available online at: http://norml.org/index.cfm?Group_ID=6891.