A new type of cigarette that contains less cancer-causing substances than conventional brands may not be doing much to protect smokers, according to new research released Tuesday.

Although testing of the new OMNI cigarettes showed that they contain 50 percent less of a particular carcinogen, or substance that causes cancer, smokers who switched to the OMNI cigarette had only 20 percent less of the carcinogen in their bodies than they did while smoking conventional cigarettes.

This relatively small drop in carcinogen levels may not be enough to reduce a smoker’s chance of developing cancer, study author Dr. Dorothy K. Hatsukami told Reuters Health. “Does that (20 percent difference) really translate to reduced cancer risk? We’re not sure,” she said.

She warned that smokers should not believe that by switching to a less carcinogenic brand, they are sidestepping the dangers of smoking.

If smokers think the new so-called “reduced-exposure” tobacco products are safe, “they’ll maintain their smoking rather than make a concerted effort to quit,” Hatsukami pointed out. “The best way to reduce your risk of disease is still quitting smoking,” she added.

Tobacco naturally contains carcinogens, which are enhanced during the processing of tobacco leaves. In order to design safer tobacco products, companies are beginning to release cigarettes and snuff products that contain fewer carcinogens, created by adding protective chemicals, processing the tobacco differently, or using genetically engineering tobacco.

In the current study, Hatsukami and her colleagues at the University of Minnesota in Minneapolis tested the benefits of reduced exposure products by asking 54 smokeless tobacco users and 51 smokers to switch to either the newer brands or a nicotine patch for four weeks. Snuff users tried Swedish snus, while smokers switched to OMNI cigarettes.

Reporting in the Journal of the National Cancer Institute, the researchers found that smokers who switched to reduced-exposure products experienced a smaller decrease in the carcinogen NNK than was predicted by machine testing. Snuff users showed lower levels of carcinogens after switching to snus, but both snuff users and smokers experienced a smaller decrease in carcinogens than nicotine patch users.

In an interview, Hatsukami explained that people smoke in a different way than machines, and some smokers may have absorbed more carcinogens by taking more puffs per cigarette or inhaling more smoke than the machine predicted.

“Consumers really need to be wary when they see advertisements for reduced exposure products,” she said.

SOURCE: Journal of the National Cancer Institute, June 2, 2004.