Smokeless tobacco products, as used in Europe and North America, do not appear to increase cancer risk. A large meta-analysis, published in the open access journal BMC Medicine, has shown that snuff as used in Scandinavia has no discernible effect on the risk of various cancers. Products used in the past in the USA may have increased the risk, but any effect that exists now seems likely to be quite small.
Peter Lee and Jan Hamling, from P.N. Lee Statistics and Computing Ltd, carried out the analysis of 89 studies from the United States and Scandinavia. They found that, after adjustment for concurrent smoking, any effect of current US products or Scandinavian snuff seems very limited. According to Lee, "It is clear that any effect of smokeless tobacco on risk of cancer, if it exists at all, is quantitatively very much smaller than the known effects of smoking".
In 2005 in US men aged 35 or over, there were a total of 142,205 deaths from seven cancers considered to be caused by smoking. If these people had never smoked, Lee and Hamling estimated that the numbers would have reduced by 104,737, with the reduction in lung cancer deaths, 79,195, being the major contributor. If smokeless tobacco was introduced to a similar population of never smokers, this meta-analysis shows that any increase in risk would be negligible compared to the lives saved by reducing cigarette use.
Lee said, "Our paper shows very clearly that, in marked contrast to smoking, smokeless tobacco use carries little or no risk of cancer. Concerns about possible effects of smokeless tobacco on oral cancer are answered by our analyses showing a lack of relationship based on the combined evidence from those 14 studies published since 1990 which allow adequate control for effects of smoking."
More information: Systematic review of the relation between smokeless tobacco and cancer in Europe and North America , Peter N Lee and Jan S Hamling , BMC Medicine (in press), www.biomedcentral.com/bmcmed/