Smokers with high levels of two chemicals in their urine are 8.5 times more likely to get cancer
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Posted on Apr 21, 2009, 10 a.m.
By gary clark
A new study has found that smokers are 8.5 times more likely to get lung cancer if two chemical byproducts of tobacco smoke are found in their urine – findings that could lead to the development of a new test to predict lung cancer risk in smokers.
Researchers from the University of Minnesota in Minneapolis analyzed metabolite levels in the urine of about 500 smokers. Drawn from the Shanghai Cohort Study and the Singapore Chinese Health Study, study subjects were divided into groups of high, medium and low levels of two key chemicals: the known carcinogen, NNAL, and the nicotine byproduct, cotinine. The researchers, who were led by Jian-Min Yuan, an associate professor of public health at the University, then followed lung cancer diagnoses for a full decade.
Those who had high levels of NNAL and cotinine were 8.5 times more likely to develop lung cancer than other smokers with low levels of both chemicals. High levels of cotinine only put people at three times the risk, while smokers with high levels of NNAL only were at twice the risk. After factoring in the number of packs of cigarettes smoked each day, as well as the number of years of smoking as reported by the participants, Yuan says it appears that the two chemicals are independent risk factors for lung cancer. But he notes that the reason is unclear. "We are thinking smokers' uptake of the tobacco carcinogens is different. Metabolic systems between smokers are different," he explains.
Yuan predicted that it would take up to five years before a commercial urine test would be available for use by doctors. "If we can identify a smoker with a high level of metabolites, and down the road they have a higher risk of lung cancer, public health workers can get them motivated to quit smoking," Yuan says. "If they can't quit, we can do more intensive screening to find very small lung cancers that can be treated." Margaret K. Offermann, deputy national vice president for research at the American Cancer Society, also says that "identifying patients with the chemical markers in their urine might help in raising the red flag in doctors' offices. One can read the riot act to smokers that they're at risk." However, she cautions against "using the lower levels to reassure people it's okay to puff away."
According to the American Cancer Society, lung tumors are the most deadly form of cancer in the United States. In 2008, 215,020 new cases of lung cancer were diagnosed, and 161,840 people died of the disease.
News Release: Smokers' urine may give cancer alert early enough to save lungs www.bloomberg.com April 19, 2009
