Dec. 26, 2003 MINNEAPOLIS / ST. PAUL (Dec. 22, 2003) --University of Minnesota researchers found that levels of a tobacco-specific lung carcinogen increased in nonsmokers when they visited a public setting where smoking is allowed. The carcinogens, metabolites of NNK, could increase their risk of lung cancer. The study is published Dec. 22 by the American Association for Cancer Research.
This study is the first to measure tobacco-specific carcinogens in nonsmokers exposed to environmental tobacco smoke (ETS) in a public setting, in this case a casino. (A previous study by the University of Minnesota examined tobacco carcinogens in nonsmoking women who were exposed to secondhand smoke at home.)
"Environmental tobacco smoke in restaurants, bars, and casinos presents a potential health hazard to employees and non-smoking patrons," said lead author Kristin Anderson, Ph.D., associate professor in the School of Public Health and Cancer Center member. "However, further studies are needed to examine the long-term health effects, on employees and patrons, of transient exposure to ETS."
Biomarkers were measured in urine samples from nonsmokers before and after a four-hour visit to a casino where smoking is allowed. The researchers tested for NNK through its urinary metabolites, NNAL and NNAL-Gluc, which are excellent biomarkers of human uptake of NNK. NNAL, like NNK, is a potent pulmonary (lung) carcinogen in rodents and a probable human carcinogen. The study found that, on average, the levels of NNK metabolites were increased two-fold (112 percent), demonstrating that exposure of nonsmokers to ETS in a public setting results in uptake of a tobacco-specific lung carcinogen.
Co-author Stephen Hecht, Ph.D., Cancer Center member and professor of Laboratory Medicine and Pathology in the Medical School, previously identified the lung carcinogen, NNK, and its metabolites NNAL and NNAL-Gluc, as tobacco-specific compounds. "There are no known sources of NNAL and NNAL-Gluc in human urine other than exposure to tobacco products," he said.
Eighteen individuals participated in the study, 14 females and 4 males. The average time spent at the casino was 4.25 hours. Participants reported that nearly all of their time was spent in the designated smoking areas. The nonsmoking area was contiguous with smoking areas. Before visiting the casino, levels of NNAL were below of the limit of detection in eleven participants. Three of these participants also had NNAL levels below the limit of detection in the after-visit samples; all others were in the detectable range.
The article is published in the journal Cancer Epidemiology Biomarkers and Prevention.
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