Smoking cannabis is often correlated with tobacco smoking and the dangers and ailments associated with its use. Such correlations are the basis for laws banning the smoking of cannabis in public places. However, a trove of studies have reported that there is little correlation between smoking cannabis and smoking tobacco, and contrary to conventional wisdom, smoking cannabis may actually improve lung health.
Conducted over a 20-year period following 5,115 adults in four U.S. cities, a 2012 study published in the Journal of the American Medical Association reported that “we found no evidence that increasing exposure to marijuana adversely affects pulmonary function.”
The study also found that unlike tobacco smokers who experience reductions in FEV1 (forced expiratory volume in the first second of expiration) and FVC (forced vital capacity), “marijuana use was associated with higher FEV1 and FVC at the low levels of exposure typical for most marijuana users.”
In what the Annals of the American Thoracic Society recognized as “the most comprehensive and authoritative review of the subject ever published,” famed medical cannabis researcher Dr. Donald Taskin, who has conducted U.S. government-sponsored studies of cannabis and lung function for over 30 years, published a 2013 study writing that the “habitual use of marijuana alone does not appear to lead to significant abnormalities in lung function.”
In the review, Dr. Taskin recognized that although smoking cannabis may be associated with “symptoms” of chronic bronchitis, cannabis smoke was not positively associated with the development of lung cancer, chronic obstructive pulmonary disease (COPD), emphysema or bullous lung disease.
The actions of cannabis that result in little, if any, pulmonary dysfunction and actually improve breathing have been attributed to the tetrahydrocannabinol (THC) in cannabis, which acts to temporarily enlarge the lung’s air passages. Effective for one to two hours after ingestion, The New England Journal of Medicine published a 1973 study finding that, “marihuana smoke, unlike cigarette smoke, causes broncho-dilation (enlarging of the air passages) rather than broncho-constriction (narrowing of the air passages) and, unlike opiates, does not cause central respiratory depression (a decrease in breathing).”
Even though this study was published decades earlier than the other studies, recognizing that cannabis can ease breathing is nothing new under the sun as it has been used for thousands of year to treat breathing difficulties and, until it was made illegal in the U.S. in 1937, was widely used to treat asthma.
A British study released in September 2018 reviewed nearly 20 observational studies involving over 25,000 subjects. This comprehensive evaluation corroborated all previous studies that cannabis smoke exposure, even long-term, is not positively associated with COPD, lung cancer or irreversible airway damage. Published in the journal Breathe, the conclusion is noteworthy when the authors comment that “cannabis use has been increasing and is likely to increase more but this should not foster hysteria.”
“The actions of cannabis that result in little, if any, pulmonary dysfunction and actually improve breathing have been attributed to the tetrahydrocannabinol (THC) in cannabis, which acts to temporarily enlarge the lung’s air passages.”
Unfortunately, hysteria is what seems to be affecting legislators, as laws are passed prohibiting cannabis smoking anywhere in public, including those areas where tobacco smoking is allowed. Although it is understandable to ban cannabis smoking in areas in which all smoking is banned, the idea of banning it in areas where tobacco is allowed is absurd.
Cannabis smokers are at risk for developing chronic bronchitis, asthma, pneumonia, cardiovascular disease and cancer from exposure to second-hand tobacco smoke. Although over 40,000 Americans die annually from second-hand tobacco smoke, studies have not concluded that there are similar ailments from exposure to second-hand cannabis smoke.
The only effect that cannabis may have on tobacco smokers is that they might be more likely to quit smoking tobacco. A study by the University College in London found that tobacco users who used cannabis to quit reduced their cigarette use by 40 percent due to the anti-anxiety properties of cannabidiol (CBD), the second most popular cannabinoid found in cannabis.
Far from preventing cannabis smokers from consuming cannabis in areas where tobacco smoking is allowed, it would be logical, reasonable and efficacious to not only allow it, but due to cannabis’ well-documented health, medical and socialization benefits, to set aside an abundant number of public areas where cannabis consumption is allowed but tobacco smoking is prohibited.