When it comes to health, smokeless tobacco users don’t get a free pass.
A new study has found that adults in the United States who used smokeless tobacco — including chewing tobacco, dipping tobacco, and snuff — had higher levels of exposure to nicotine and a type of cancer-causing compound called nitrosamines than cigarette smokers.
“Nicotine explains why smokeless tobacco is addictive and exposure to nitrosamines may at least partly explain why smokeless tobacco is known to cause cancers of the mouth, esophagus, and pancreas,” Eric Jacobs, Ph.D., a cancer epidemiologist and strategic director of pharmacoepidemiology at the American Cancer Society, told Healthline.
The data for the study come from an annual nationwide health and nutrition survey. More than 23,000 American adults participated from 1999 to 2012.
As part of the survey, people reported how often they had used cigarettes or smokeless tobacco products during the previous five days.
The survey also included measurements of tobacco-related biomarkers in their blood or urine. These markers show whether someone has been exposed to chemicals found in tobacco products.
Looking at Biomarkers
In the study, researchers from the U.S. Food and Drug Administration and the U.S. Centers for Disease Control and Prevention (CDC) looked at biomarkers for nicotine, one type of nitrosamine, lead, and four other compounds.
The average blood level of the nicotine biomarker was higher in people who only used smokeless tobacco compared to people who only smoked cigarettes.
Those who exclusively used smokeless tobacco also had higher urine levels of the biomarker for the cancer-causing nitrosamine — more than two-and-a-half times higher than people who only smoked cigarettes.
Smokeless tobacco users also had higher levels of lead in their blood than people who didn’t use any tobacco products, but they had similar levels as cigarette smokers.
The study authors note, however, that more research is needed to show that the lead levels are directly related to the use of smokeless tobacco and not other factors.
These results, published online today in Cancer Epidemiology, Biomarkers & Prevention, are in line with some previous smaller studies.
Men and Young Adults at Greater Risk
According to the CDC, around 7 percent of men over 18 reported using chewing tobacco or snuff in the past 30 days. For men aged 18 to 25, the rate is about 10 percent.
Teenagers also use smokeless tobacco.
“While the new study included only adults,” said Jacobs, “results from the 2014 National Youth Tobacco Survey indicate that nearly 10 percent of high school boys have used smokeless tobacco in the last 30 days, emphasizing the importance of preventing use of all forms of tobacco by youth.”
While smokeless tobacco is sometimes marketed as being safer than cigarettes, it is still associated with cancers of the mouth, esophagus, and pancreas. Nicotine is also a highly addictive substance.
The most harmful compounds in tobacco are the cancer-causing nitrosamines. Their level varies among smokeless tobacco products, something that wasn’t measured in the new study.
No Data on Frequency of Use
The national health survey also didn’t ask people about their use of other smokeless tobacco products such as snuff or dissolvable tobacco products. Or how often they used smokeless tobacco.
“Detailed information on the amount of smokeless tobacco used, together with the biomarkers of nicotine and carcinogen exposure,” said Jacobs, “could have helped us understand how much exposure to nicotine and carcinogens occur at specific levels of smokeless tobacco use.”
Without this information, it is difficult to tell why smokeless tobacco users and cigarettes smokers are exposed to different amounts of tobacco compounds.
The authors write that it could be due to differences among tobacco products or how people are using them.
A new large study is already gathering more information on biomarkers and tobacco use that should answer some of these questions.
However, the current study still has much to offer.
“Even without this detailed information,” said Jacobs, “results from this nationally representative study provide a good snapshot of typical levels of carcinogen and nicotine exposure in current smokeless tobacco users in the United States.”