A new study has found that smokeless tobacco, the kind users put between cheek and gum may be almost as effective as cigarettes in delivering nicotine and carcinogens.

Smokeless tobacco, the kind users put between cheek and gum, is one way to satisfy a craving for nicotine without offensive smoke. But a new study has found that it may be almost as effective as cigarettes in delivering nicotine and carcinogens.

Researchers tested the urine of 420 smokers and 182 users of smokeless tobacco for cotinine, a marker of nicotine exposure, and for a group of closely related powerful carcinogens called NNAL. The subjects had been recruited for smoking reduction studies, and the measurements were taken just before the studies began.

Smokeless tobacco users had, on an average, 74 per cent higher levels of NNAL in their urine than smokers, and 94 per cent higher levels of cotinine.

In animal studies, NNAL has been shown to be highly carcinogenic, causing tumours in the lung, pancreas, nasal mucosa and liver of rats. "The main message of this study is that smokeless tobacco cannot be regarded as safe, because it delivers just as much of one of the carcinogens in cigarette smoke as cigarettes do," said Stephen S Hecht, the lead author of the study, published in the August issue of Cancer Epidemiology, Biomarkers and Prevention, and a professor of laboratory medicine at the University of Minnesota. "While it may be safer than cigarettes, it is not nearly safe enough," he added.

Countering suggestions that smokeless tobacco might be a less harmful alternative for people unable to give up tobacco, the researchers wrote that smokeless tobacco is very risky, and should be discouraged.