Smokers who substantially reduce the number of cigarettes they smoke per day are exposed to lower amounts of a potent tobacco carcinogen; however, the reduction in the amount or concentration of the carcinogen exposure is often transient and is not proportional to the reduction in cigarettes smoked. These study results appear in the January 21 issue of the Journal of the National Cancer Institute.

Cigarette smoking is the cause of 90% of the world's lung cancer cases, but it is not known whether smokers who reduce the number of cigarettes smoked per day also decrease their risk of lung cancer.

Stephen S. Hecht, Ph.D., of the University of Minnesota Cancer Center, Minneapolis, and colleagues set out to answer this question by measuring the metabolites of a specific tobacco carcinogen in the urine of smokers who were part of a structured smoking reduction program. The carcinogen, NNK, along with polycyclic aromatic hydrocarbons, are some of the most important tobacco carcinogens with respect to lung cancer.

The people in the study, who overall had smoked an average of 23.7 cigarettes per day, gave two urine samples 1 week apart before reducing their cigarette consumption by 25% for 2 weeks, 50% for another 2 weeks, and then by 75% for the duration of the study. Urine samples were collected at several specific points throughout the 6-month study period to measure levels of the NNK metabolites, called NNAL and NNAL-Gluc. The researchers also measured the level of the compound anatabine to biochemically verify the patients' self reports of cigarette consumption. Patients were offered nicotine replacement therapy to assist their smoking reduction efforts.

Overall, there was a reduction in NNAL and NNAL-Gluc levels at nearly all of the intervals as the 92 patients who completed the study reduced the number of cigarettes smoked each day. However, the magnitude of the reduction was generally less than the reduction in cigarettes smok
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Contact: Katherine Arnold
jncimedia@oupjournals.org
301-841-1287
Journal of the National Cancer Institute
20-Jan-2004

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