Users of smokeless tobacco are exposed to higher amounts of tobacco-specific carcinogenic molecules than cigarette smokers, according to researchers at the University of Minnesota Cancer Center.

In a study comparing 182 chewing tobacco or 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, in a news release. “The only likely safe alternative to smoking is the long term use of nicotine replacement therapy as a means to reduce dependence.”

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.

Hecht and his colleagues found that levels of various known carcinogens were higher in the urine of snuff users than smokers, when adjusted for age and gender, according to the findings reported in the August issue of Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research. .

“American smokeless tobacco manufacturers are forbidden by federal law from claiming that smokeless tobacco is a safer alternative to smoking,” Hecht added. “That does not prevent them from advancing the general concept that snuff can be used as a substitute for cigarettes, especially in places, like an office setting, where snuff may be acceptable while smoking is not.”