A 20 year study from the Journal of the American Medical Association suggests evidence that marijuana DOES NOT do the same kind of damage tobacco does.
The study, published in the Jan. 10, 2012 issue found occasional pot smokers – who used a median of roughly two to three joints per month – had normal lung function compared to tobacco smokers in the study. This results from one of the largest and longest studies on the health effects of marijuana.
The data suggest that using marijuana often, might cause a decline in lung function, but there weren’t enough heavy users among the 5,000 young adults in the study to draw firm conclusions. Still, the authors recommended “caution and moderation when marijuana use is considered.” Marijuana is an illegal drug under federal law although some states allow its use for medical purposes.
The study by researchers at the University of California, San Francisco, and the University of Alabama at Birmingham was released Tuesday by the Journal of the American Medical Association. The findings echo results in some smaller studies that showed while marijuana contains some of the same toxic chemicals as tobacco, it does not carry the same risks for lung disease.
Not all doctors were even convinced that marijuana had zero impact on a person’s lung health. For the study, researchers gave two kinds of pulmonary function tests that gauge a person’s ability to inhale and exhale. The study did not look at lung cancer, or other disease rates among pot-smokers.
The study randomly enrolled 5,115 men and women aged 18 through 30 in four cities: Birmingham, Chicago, Oakland, Calif., and Minneapolis. Roughly equal numbers of blacks and whites took part, but no other minorities. Participants were periodically asked about recent marijuana or cigarette use and had several lung function tests during the study.
Overall, about 37 percent reported at least occasional marijuana use, and most users also reported having smoked cigarettes; 17 percent of participants said they’d smoked cigarettes but not marijuana. Those results are similar to national estimates.
On average, cigarette users smoked about 9 cigarettes daily, while average marijuana use was only a joint or two a few times a month – typical for U.S. marijuana users, Kertesz said.
Dr. Donald P. Tashkin, a marijuana researcher at the David Geffen School of Medicine at UCLA, told WebMD the study should not be taken as the final word on marijuana’s safety for pot smokers.
“The smoke in marijuana contains thousands of ingredients, many of which are toxic and noxious and have the potential, at least, to cause airway injury,” Tashkin said. “In an ideal world, it would be preferable to take it in another form.”