UMN study shows regulation is needed for cancer causing chemicals in smokeless tobacco products

Thursday, December 18, 2014

New research from the University of Minnesota shows the level of cancer causing chemicals in smokeless tobacco products varies widely, and these levels play an important role in the extent of the body’s exposure to these chemicals even when taking into account how the product is used. The results indicate a need for FDA-mandated standards on smokeless tobacco products to protect public health.

The study is published in the latest issue of Cancer Prevention Research, a journal of the American Association for Cancer Research.

“Tobacco-specific nitrosamines are one of the most potent cancer-causing agents,” said Dorothy K. Hatsukami, PhD, associate director of Cancer Prevention and Control at the Masonic Cancer Center, University of Minnesota and the Forster Family Professor in Cancer Prevention and professor of psychiatry at the University of Minnesota. “Our research confirms different brands of smokeless tobacco contain varying levels of these agents. This means the amount of exposure to these chemicals depends not only on a person’s pattern of use, but also the product they choose to use.”

Previous research out of the Masonic Cancer Center demonstrates the association of tobacco- specific nitrosamines exposure with lung cancer risk. Landmark results from the lab of Stephen Hecht, Ph.D., the Wallin Professor of Cancer Prevention and professor in the Department of Laboratory Medicine and Pathology at the University of Minnesota, were the first to analyze, chemically synthesize, and assess tobacco-specific carcinogens associated with cancer risk.

Smokeless tobacco use has also been linked to greater risks for oral and esophageal cancer, compared to non-use, and pancreatic cancer may also be linked to smokeless tobacco use.

“There is tremendous variability in levels of tobacco-specific nitrosamines across different brands of smokeless tobacco products,” said Hatsukami. “The majority of smokeless tobacco users in the United States are not aware of the levels of cancer-causing chemicals in their smokeless tobacco products or of the tremendous variability in the levels of these chemicals across brands.”

To study this, Hatsukami, , and their colleagues analyzed data from 391 adults from Minneapolis/St. Paul, Eugene, Oregon, and Morgantown, West Virginia, who used smokeless tobacco products daily. The smokeless tobacco brands used by different participants varied in nicotine and tobacco-specific nitrosamine content. Participants could not be current users of other tobacco or nicotine products.

At two assessment sessions, approximately one week apart, demographic and smokeless tobacco-use history and urine samples were collected from participants. Urine samples were analyzed for biomarkers of exposure to nicotine and the tobacco-specific nitrosamines N’-nitrosonornictoine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK).

Analysis showed that levels of biomarkers of NNN and NNK in users’ urine samples were independently positively correlated with number of years of daily smokeless tobacco use, number of tins of smokeless tobacco used each week, mean daily dip duration, and levels of NNN and NNK in the smokeless tobacco products used. For every one unit (µg/g wet weight) increase of NNK and NNN in the smokeless tobacco product used, the estimated increase of the corresponding biomarkers was 32 percent and 12 percent, respectively.

“Now that the FDA has the authority to establish product standards and mandate the reduction of harmful and potentially harmful ingredients in tobacco products, it’s important to better understand how products vary and how the different levels of exposure affect people,” said Hatsukami. “We believe our research shows a clear need for regulation of these cancer-causing agents in all smokeless tobacco products. At minimum, the FDA should provide consumers information about the different levels of cancer-causing agents in different brands of smokeless tobacco.”

This study was funded through a grant from the National Cancer Institute, R01 CA141531.