Smokeless tobacco products expose users to nicotine and other harmful substances.
Use of smokeless tobacco products is attracting increasing attention from the public health community. Though smokeless tobacco use is less common than cigarettes, it is prevalent among certain population groups, particularly men and young people.
The National Adult Tobacco Survey estimates that 7.1% of American men used chewing tobacco, snuff, dip, snus or dissolvable tobacco products in 2012-13.
Among US high school students, the National Youth Tobacco Survey (NYTS) found that 9.6% of males used chewing tobacco, snuff or dip and 2.7% used snus - a tobacco product that is put in the mouth - in 2013.
Since 2000, cigarette smoking prevalence has declined, but smokeless tobacco use among US youth has remained relatively consistent.
This is a cause for concern because it has been found to have several adverse health effects and has been identified as a cause of cancer.
Smokeless products known to contain carcinogens
Previous small studies have found high levels of toxic constituents, including carcinogens, in smokeless tobacco users, but more analysis of nationally representative data has been needed.
Lead author Brian Rostron, PhD, an epidemiologist in the Center for Tobacco Products at the US Food and Drug Administration (FDA), and colleagues examined data for 23,684 adult participants in the National Health and Nutrition and Examination Survey (NHANES) - a large, nationally representative study of US health behaviors and outcomes from 1999-2012.
They recorded participant-reported cigarette and smokeless tobacco use and categorized individuals into four groups: 16,313 non-tobacco users, 488 exclusive smokeless tobacco users, 6,791 exclusive cigarette smokers and 92 dual cigarette and smokeless tobacco users.
They analyzed biomarkers of exposure to seven tobacco constituents, including nicotine and tobacco-specific nitrosamine.
High levels of cotinine and NKK exposure in smokeless product use
The level of cotinine, the biomarker of nicotine exposure, was higher in exclusive smokeless tobacco users compared with exclusive cigarette smokers. The biomarker of NNK exposure was also higher in exclusive smokeless tobacco users compared with exclusive cigarette smokers.
The analysis confirms that levels of biomarkers of exposure to nicotine and the cancer-causing tobacco constituent NNK are higher among exclusive smokeless tobacco users than exclusive cigarette smokers. This continues to put smokeless tobacco users at risk for adverse health effects, including cancer.
Rostron says the findings confirm the need to continue studying of the toxic constituents of smokeless tobacco and their health effects on the individuals who use them.
The FDA and Centers for Disease Control and Prevention (CDC) are continuing to analyze and monitor biomarker levels among tobacco users.
In addition, the FDA and National Institutes of Health (NIH) are collaborating on the Population Assessment of Tobacco and Health (PATH) Study - a large longitudinal study that involves collection of biospecimens such as blood and urine.
Limitations of the current study include the nature of the data collected in NHANES. Being a general health survey, there is no detailed information on the type of smokeless tobacco product used, the quantity of smokeless tobacco product used and the duration or former use of smokeless tobacco products.
However, Rostron notes that the PATH Study data will allow for more specific analyses of tobacco use and harm.
The authors conclude:
"Our results have shown that smokeless tobacco users have high levels of known harmful and addictive constituents and that in some cases these levels are higher than those observed among cigarette smokers.
This finding is a cause of considerable concern for individual and public health. These results thus demonstrate the need for continuing study of the toxic constituents of smokeless tobacco as well as their health effects on the individuals who use them."
Medical News Today recently reported that flavored tobacco could be causing some young people taking up smoking.