CDC researchers find higher levels in U.S. brands than foreign brands
WEDNESDAY, June 2 (HealthDay News) -- Smokers of certain U.S. cigarette brands take in higher levels of cancer-causing tobacco-specific nitrosamines (TSNAs) than smokers of some foreign cigarette brands tested in a study published online May 25 in Cancer Epidemiology Biomarkers & Prevention.
David L. Ashley, Ph.D., of the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues enlisted 126 daily smokers from Australia, Canada, the United Kingdom and the United States to collect the butts of cigarettes each smoked over a 24-hour period. The butts then were tested to estimate how much TSNA (in particular, 4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone [NNK]) entered the smokers' mouths during that period. The researchers also collected urine samples from study subjects to test for the presence of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a metabolite from the breakdown of the TSNA.
The researchers found that, as the mouth-level exposure of NNK increased, the urinary level of NNAL increased. However, the relationship between mouth-level nicotine exposure and its salivary metabolite, cotinine, was not found to be significant.
"Internal dose concentrations of urinary NNAL are significantly lower in smokers in countries that have lower TSNA levels in cigarettes such as Canada and Australia in contrast to countries that have high levels of these carcinogens in cigarettes, such as the United States. Lowering the levels of NNK in the mainstream smoke of cigarettes through the use of specific tobacco types and known curing practices can significantly affect the exposure of smokers to this known carcinogen," the authors write.
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