Investigators discovered that African-American smokers may have significantly lower levels of an enzyme that metabolizes nicotine and nicotine by-products, compared to Caucasians who were exposed to identical nicotine patches. The findings suggest that African Americans may experience higher nicotine levels per cigarette, which would help explain why quit rates are lower among this group.
Smokers adjust their level of smoking to maintain blood levels of nicotine, which are determined in part by rates of nicotine metabolism, and while we cant say from this study that differences in metabolism definitively account for lower quit rates, it could very well have an impact, said Jeannette Zinggeler Berg, an M.D./Ph.D. student in Biochemistry, Molecular Biology, and Biophysics at the University of Minnesota.
In past studies, elevated levels of the nicotine-related molecule, cotinine, have been observed in African-American smokers compared to Caucasian smokers. Cotinine is a direct metabolite of nicotine a product of nicotine metabolism and so it is a marker for exposure to tobacco, Berg says. It is not carcinogenic and is not an addictive component of tobacco, but the more of it a person has in their blood, the more nicotine they have been exposed to, Berg said.
But researchers have debated whether differences in cotinine seen in African Americans is due to the common use of menthol cigarettes by the group, or to the fact that these smokers may be getting more nicotine per cigarette because they are smoking longer or inhaling more deeply.
In this study, Berg and her colleagues examined different markers of nicotine metabolism in 95 daily smokers who, during the study period, were required not to smoke and to wear a nicotine patch. They specifically looked at levels of glucuronides, wh
|Contact: Greg Lester|
American Association for Cancer Research