Friday December 17 12:12 PM ET
WASHINGTON (Reuters) - Smoking marijuana can cause cancer, California researchers said Friday, and aging baby boomers who have been indulging since the swinging 60s may just be starting to feel its ravages.
The report, by Dr. Zuo-Feng Zhang of the Jonsson Cancer Center at the University of California Los Angeles, adds to evidence that smoking cannabis can have cancer-causing effects similar to those linked to cigarette smoking.
``Many people may think marijuana is harmless, but it's not,'' Zhang said in a statement. ``The carcinogens in marijuana are much stronger than those in tobacco. The big message here is that marijuana, like tobacco, can cause cancer.''
Writing in the journal Cancer Epidemiology Biomarker and Prevention, Zhang said he studied 173 patients diagnosed with head and neck cancer, and compared them to 176 cancer-free control patients.
Those who said they habitually smoked marijuana were more likely to be in the group with head and neck cancers. And the more they smoked, the bigger the risk.
``If you smoke a little, your risk increases a little,'' Zhang said. ``If you smoke a lot, your risk increases a lot.''
He said pot-smoking baby boomers should be on the lookout for symptoms of head and neck cancer, also very common in cigarette smokers and heavy drinkers.
``In the '60s, we had very high numbers of people in their 20s smoking marijuana,'' Zhang said. ``These people are just now getting to the ages at which they will get head and neck cancers.''
Earlier this year, the Institute of Medicine at the National Academy of Sciences reported that marijuana could have some medical uses, notably to treat pain for some terminally ill patients.
But the committee said pills using the active ingredients in marijuana were a safer alternative because smoking marijuana can cause cancer, lung damage and babies with low birth weights in pregnant women.