(As reported by Fred Gardner on AlterNet, August 28, 2009)
Conclusion/findings from “Marijuana Use and the Risk of Upper Aerodigestive Tract Cancers: Results of a Population-Based Case-Control” by Prof. Donald Tashkin, University of California at Los AngelesYou’d think it would have been very big news in June 2005 when UCLA medical school professor Donald Tashkin reported that components of marijuana smoke — although they damage cells in respiratory tissue — somehow prevent them from becoming malignant.
In other words, something in marijuana exerts an anti-cancer effect!
Tashkin has special credibility. He was the lead investigator on studies dating back to the 1970s that identified the components in marijuana smoke that are toxic.
It was Tashkin, et. al., who published photomicrographs showing that marijuana smoke damages cells lining the upper airways. It was the Tashkin lab’s finding that benzpyrene — a component of tobacco smoke that plays a role in most lung cancers — is especially prevalent in marijuana smoke.It was Tashkin’s data showing that marijuana smokers are more likely than non-smokers to cough, wheeze, and produce sputum.
The National Institute on Drug Abuse (NIDA), which supported Tashkin’s marijuana-related research over the decades, readily gave him a grant in 2002 to conduct a large, population-based, case-controlled study that would prove definitively that heavy, long-term marijuana use increases the risk of lung and upper-airways cancers.
What Tashkin and his colleagues unexpectedly found, however, disproved their hypothesis.
Tashkin’s team interviewed 1,212 cancer patients from the Los Angeles County Cancer Surveillance program, matched for age, gender, and neighborhood with 1,040 cancer-free controls. Marijuana use was measured in “joint years” (number of years smoked times number of joints per day).
It turned out that increased marijuana use did not result in higher rates of lung and pharyngeal cancer, whereas tobacco smokers were at greater risk the more they smoked. Tobacco smokers who also smoked marijuana were at slightly lower risk of getting lung cancer than tobacco-only smokers.
Without a NIDA press release calling attention to its significance, the editors of America had no idea that “Marijuana Use and the Risk of Lung and Upper Aerodigestive Tract Cancers: Results of a Population-Based Case-Control Study” was a blockbuster story.
Marijuana Doesn’t Cause COPD, Either
The accelerated development of chronic obstructive pulmonary disease — COPD — is another condition prevalent among tobacco smokers. Chronic bronchitis and emphysema are two forms of COPD, which is the fourth-leading cause of death in the U.S. Air pollution and tobacco smoke are known culprits.
Tashkin and his UCLA colleagues conducted a major study in which they measured the lung function of various cohorts over eight years and found that tobacco-only smokers had an accelerated level of decline, but marijuana smokers — even if they smoked tobacco as well — experienced the same rate of decline as non-smokers.
“The more tobacco smoked, the greater the rate of decline,” Tashkin said. “In contrast, no matter how much marijuana was smoked, the rate of decline was similar to normal.”
Tashkin concluded that his and other studies “do not support the concept that regular smoking of marijuana leads to COPD.”
Editor’s note: Ron Marczyk is a retired high school health education teacher who taught Wellness and Disease Prevention, Drug and Sex Ed, and AIDS educaiton to teens aged 13-17.
He also taught a high school International Baccalaureate psychology course. He taught in a New York City public school as a Drug Prevention Specialist. He is a Registered Nurse with six years of ER/Critical Care experience in NYC hospitals, earned an M.S. in cardiac rehabilitation and exercise physiology, and worked as a New York City police officer for two years.
Currently he is focused on how evolutionary psychology explains human behavior.