More Evidence That Smokeless Tobacco Products in the U.S. Have Low TSNA Levels
Posted Oct 04 2012 1:47pm
New data shows that tobacco-specific nitrosamines (TSNAs) were at very low levels in almost all popular smokeless products available in the U.S. in 2006 and 2007. The findings appear in a research article in Regulatory Toxicology and Pharmacology (abstract here ) authored by M.F. Borgerding and other scientists at RJ Reynolds Tobacco Company.
TSNA levels for specific brands are listed in the table below. In reviewing the data, one should consider these points:
1. The table lists levels in parts per million (ppm) by weight, or micrograms of TSNAs per gram of dry product. This allows products with different moisture levels (e.g., dissolvable tobacco at 4% and moist snuff at about 50%) to be compared directly.
2. ALL of the American products had low TSNA levels, especially when compared to products from the 1970s and 1980s (described here ). In the early 1980s, it was common to see moist snuff products with TSNA levels at 40-80 ppm; by the end of the decade, most products were under 40 ppm. With rates declining further, to around 20 ppm in 1995, analytic reports ceased.
3. Several Swedish snus products were analyzed; all had TSNA levels below 2 ppm.
4. The lowest TSNA levels were found in Ariva (0.1 ppm) and Stonewall (0.4 ppm) dissolvable tobacco pellets made by Star Scientific, Inc. ( here ).
5. Chewing tobacco products all had levels below the Gothiatek standard, which is 10 parts per million. Gothiatek was developed by Swedish Match in the late 1990s to serve as a voluntary standard for maximum levels of some contaminants (described here ).
6. The highest TSNA levels (12-41 ppm) were found in powdered dry snuff, a form of tobacco historically favored by older Southern women, but steadily declining in popularity (evidence here ). When I worked with an investigator at the Swedish National Food Administration to analyze TSNAs in American products in 2003, we found very high levels in two powdered dry snuff brands ( abstract here ).
How do smokeless tobacco TSNA levels compare with those in cigarettes? The Reynolds scientists did not test cigarettes, but I did. Camel and Marlboro cigarettes had TSNA levels around 7 ppm in 2003, putting them in the same range as many moist snuff and chewing tobacco products. However, TSNAs are but one of many thousands of toxins delivered in smoke, so comparing these agents in cigarettes and smokeless is almost meaningless.
A National Cancer Institute fact sheet describes TSNAs as “the most harmful chemicals in smokeless tobacco…” ( here ), but this study shows that TSNAs are present in tiny concentrations. As discussed in a previous post ( here ), there is virtually no evidence that current TSNA levels are associated with any measurable cancer risks.
TSNA Levels in Smokeless Tobacco Products in the U.S., 2006 and 2007