The relative risks of a low-nitrosamine smokeless tobacco product compared with smoking cigarettes: estimates of a panel of experts.

A nine-membered panel of experts was asked to determine expert opinions of mortality risks associated with use of low-nitrosamine smokeless tobacco (LN-SLT) marketed for oral use. A modified Delphi approach was employed. For total mortality, the estimated median relative risks for individual users of LN-SLT were 9% and 5% of the risk associated with smoking for those ages 35 to 49 and > or =50 years, respectively. Median mortality risks relative to smoking were estimated to be 2% to 3% for lung cancer, 10% for heart disease, and 15% to 30% for oral cancer. Although individual estimates often varied between 0% and 50%, most panel members were confident or very confident of their estimates by the last round of consultation. In comparison with smoking, experts perceive at least a 90% reduction in the relative risk of LN-SLT use. The risks of using LN-SLT products therefore should not be portrayed as comparable with those of smoking cigarettes as has been the practice of some governmental and public health authorities in the past. Importantly, the overall public health impact of LN-SLT will reflect use patterns, its marketing, and governmental regulation of tobacco products.