PHILADELPHIA It may not be inhaled into the lungs, but smokeless tobacco exposes users to some of the same potent carcinogens as cigarettes. In the August issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, researchers at the University of Minnesota Cancer Center report that users of smokeless tobacco are exposed to higher amounts of tobacco-specific nitrosamines -- molecules that are known to be carcinogenic -- than smokers.

Smokeless tobacco, also known as oral snuff, is a variant on chewing tobacco that users suck on by slipping it between their cheeks and gums. In a study comparing 182 oral snuff users with 420 cigarette smokers, the Minnesota researchers found that snuff users were exposed to higher levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) than smokers. NNK is a human carcinogen known to produce lung cancer as well as cancers of the pancreas, nasal mucosa and liver in laboratory animals.

Smokeless tobacco products have been proposed by some as safer alternatives to cigarettes, but they are not safe, said author Stephen S. Hecht, Ph.D., professor of cancer prevention at the University of Minnesota Cancer Center. The only likely safe alternative to smoking is the long term use of nicotine replacement therapy as a means to reduce dependence.

In fact, this study lends evidence to support the notion that the oral use of tobacco actually provides a more efficient means for delivering certain carcinogens into the body through the bloodstream, although cigarette smoke includes a host of carcinogenic products that arent a major factor in smokeless tobacco, Hecht said.

The study participants included men and women aged 17 to 80 who had sought but had yet to begin treatment for tobacco addiction, and who used conventional, popular U.S. brands of smokeless tobacco. The researchers studied nitrosamine exposure by analyzing the urine of par
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Contact: Greg Lester
lester@aacr.org
267-646-0554
American Association for Cancer Research
9-Aug-2007