Smokeless Tobacco & Prostate Cancer

Snus is a smokeless, moist pouch tobacco sold in teabag-like sachets that you place under your upper lip. It was created in Sweden, where it is credited with lowering smoking rates. More than half of Swedish snus consumers are ex-smokers. Like pipe tobacco, snus is available in a multitude of flavors, from cinnamon and chili to whiskey and wintergreen. Snus contains nicotine, so it is addictive. It also contains more nicotine than comparable combustible tobacco products. But that's not what is concerning scientists who are studying its effects at Harvard Medical School.

"Snus has been suggested as a less harmful alternative to smoking because it lacks the combustion products of smoking that are associated with cancer risk. However, we found that men with prostate cancer who used snus were at increased risk of premature death," said Kathryn Wilson, a research scientist in the Department of Epidemiology at Harvard Chan School and the co-first author of a study on snus and prostate cancer progression.

The scientists examined health data gathered from Swedish construction workers during preventive health check-ups between 1971 and 1992. The data included a tobacco use questionnaire completed during each man's initial check-up. Of these men, 9,582 later developed prostate cancer. About half of the subjects died during the follow-up period – 2,489 of them from prostate cancer.

Those who consumed snus but did not smoke had a 24 percent increased risk of dying from prostate cancer, compared with those who never used tobacco. They also had a 19 percent increased risk of dying during the study period from any cause. Among men whose cancer had not spread, the increased risk of death from prostate cancer for exclusive snus users was three times higher than for never-users of tobacco.

"There is some evidence from animal studies that nicotine can promote cancer progression, and snus users have high blood levels of nicotine. Snus users are also exposed to other carcinogens in tobacco even though it is a smokeless product," said Sarah Markt, research associate in the Department of Epidemiology. "Taken together, this suggests that the health effects of smokeless tobacco products should be carefully studied by public health officials."

The study has been published in the International Journal of Cancer.