Will cannabis legalization lead to an increase in tobacco use in Canada?

A researcher from the University of Toronto is suggesting that in order to prevent cannabis legalization from resulting in increased rates of tobacco use, smoking cannabis should be discouraged in favor of other methods of consumption

The government needs to encourage alternative forms of consuming legal marijuana rather than smoking, says a University of Toronto Professor in a recent submission to the Canadian Medical Association Journal.

Robert Schwartz, who in addition to his position as Professor at U of T’s Dalla Lana School of Public Health, is a Senior Scientist at the Centre for Addiction and Mental Health, holds a faculty association at the university’s school of Public Policy and Governance, works with the Ontario Tobacco Research Unit (OTRU) to help educate the public on the risks of tobacco smoke, and has published extensively on the subject.

Public policy experts in Canada have worked extensively to decrease tobacco use, seeing rates of consumption cut in half over the past 40+ years. Schwartz’s concern is that nonsmokers can be introduced to tobacco through social circles when cannabis is mixed or ‘mulled’ with tobacco. In Ontario, he points out that almost one-third of pot smokers “mull or mix tobacco with their marijuana, and 31% are not regular tobacco smokers.”

To address this concern, as well as several health concerns associated with smoking marijuana, Schwartz suggests a legalization framework that discourages smoking, especially in public, and encourages alternative modes of ingestion like edibles or vaporizing.

Schwartz’s piece on the concerns with smoking cannabis breaks down into a handful of key points:

  • When legalized, policies should prefer safer modes of consuming marijuana over smoking, including health warning labels, graduated limits on supply, allowing only non-smoked marijuana consumption in public, and taxes that make smoked marijuana more expensive than alternative modes of consumption.
  • Widespread smoking of marijuana in public may risk renormalization of smoking in general.
  • There are at least 33 known carcinogens in marijuana smoke.
  • Marijuana smoking is associated with cancer, respiratory problems, and cardiovascular disease.

In addition to these key points, the article breaks down much of the known research on the subject, pointing out that there is still little conclusive research on the impacts of cannabis smoke on the lungs.

“Currently, evidence about the actual effects of marijuana smoke on cancer is suggestive but not conclusive.There are not enough high-quality, rigorous clinical and cohort studies of marijuana smoking, particularly those involving regular long-term use.”

The author highlights some key points for policy makers in Canada to consider, like the fact that California has listed marijuana smoke as a carcinogen. He also points to a review by the Office of Environmental Health Hazard Assessment that found associations between marijuana smoking and cancers of the lung, head and neck, bladder, brain, and testes, as well as one showing associations with parental cannabis use and childhood cancer, and a handful of other studies showing issues with respiratory problem and myocardial infarction.

But he also notes that a recent article that collected results from within the International Lung Cancer Consortium “found little evidence of increased risk of lung cancer among habitual or long-term marijuana smokers.”

“We know enough about the health effects of smoking marijuana to invoke the precautionary principle and recommend that it be discouraged in every way possible. There is a need for action to ensure prevention of increased tobacco smoking as marijuana is legalized. Public health policy should actively prefer non-smoked forms of the drug”.

Additional citation here.

Featured image via Dave Chan.

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