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Relative Safety Of Moderate Marijuana Smoking Not Challenged By New Study

(Received via e-mail Aug. 20, 1998)

Los Angeles-- Long-term marijuana smokers may develop pre-cancerous changes in bronchial cells at similar rates to tobacco smokers, suggests a UCLA study reported in this week's Journal of the National Cancer Institute.

NORML board member Dr. John Morgan of the City University of New York (CUNY) Medical School said that the data must not overshadow decades of research illustrating the relative safety of moderate marijuana smoking. "There are no epidemiological or aggregate clinical data showing higher rates of lung cancer in people who smoke marijuana," he said. Morgan noted that a decade long study completed by Kaiser Permanente last year found no increase in deaths among 14,000-plus marijuana smokers when compared to nonsmokers.

"Like tobacco smoke, marijuana smoke contains a number of irritants and carcinogens," Morgan said. "However, most marijuana-only smokers in the United States probably do not ingest enough smoke to cause serious lung damage." Marijuana smokers in the UCLA study admitted smoking 10 joints or more per week for the past five years. Most recreational marijuana users smoke far less than that, Morgan speculated.

Morgan added that THC, one of the chief active ingredients in marijuana, does not appear to be carcinogenic and may offer protection against the development of some malignancies. He pointed to the results of a $2 million federal study demonstrating that rats fed huge doses of THC over long periods failed to develop cancer and had fewer tumors than rats not given the compound.

The UCLA study found that 54 percent of tobacco smokers and 67 percent of marijuana smokers showed evidence of potentially cancerous molecular alternations in their lung tissues. Only 11 percent of nonsmokers showed any pre-cancerous changes.

Habitual smokers of tobacco and marijuana had a 100 percent incidence of basal cell hyperplasia, a genetic marker associated with increased risk of lung cancer. One-hundred-and-four people participated in the study.

NORML Executive Director R. Keith Stroup, Esq. said the study's findings do not justify arresting and jailing marijuana smokers. "Any risk presented by marijuana smoking falls well within the ambit of choice we permit the individual in a free society," he said. "We do not suggest that marijuana is totally harmless or that it cannot be abused. That is true for all drugs, including those which are legal. Clearly, however, marijuana's relative risk to the user and society in no way warrants arresting more than 642,000 marijuana smokers each year."

Stroup added that the research strengthened the need to reform federal and state laws that forbid the use of paraphernalia that limits the amount of noxious smoke inhaled by marijuana consumers. "Any potential health risk from marijuana smoking comes from the consumption of carcinogenic smoke, not the active compounds in marijuana. It is counter-productive for the government to forbid the use of products like vaporizers that can greatly reduce this particular risk to the lungs."

For more information, please contact either Dr. John Morgan of CUNY Medical School, (212) 650-8255, or Paul Armentano of The NORML Foundation, (202) 483-8751. Copies of the 1997 Kaiser Permanente marijuana and mortality study are available upon request from The NORML Foundation.