Racial and ethnic differences in nicotine metabolism exist among adolescent smokers

New research by scientists with the National Institute on Drug Abuse (NIDA), National Institutes of Health, suggests that some of the racial and ethnic differences underlying how adults' bodies metabolize nicotine also are at work during adolescence.

The findings have implications for the way teens of different racial and ethnic backgrounds are provided smoking cessation treatments. The study is published in the January 2006 issue of Ethnicity and Disease.

“Previous research in adults showed that black smokers take in 30 percent more nicotine per cigarette and take longer to rid their bodies of the drug, compared to white smokers,” says NIDA Director Dr. Nora D. Volkow. “The current findings, among the first on adolescent nicotine metabolism, reveal that these differences are in effect during the teen years, as well.”

“Because nicotine plays an active role in smoking reinforcement, these variations may influence early onset addiction to tobacco,” Dr. Volkow adds. “Thus, these findings may constitute a strong warning to black youth to keep from smoking in the first place. They also may explain why certain smoking cessation therapies work better in some populations than in others, and therefore, which treatments should be offered to which teens.”

A team of scientists led by Dr. Eric T. Moolchan, Director of NIDA's Teen Tobacco Addiction Research Clinic in Baltimore, Maryland, recruited 61 white and 30 black adolescent smokers to participate in the study.

The scientists measured the ratio of one nicotine breakdown product to another to assess the rates at which the teens’ bodies disposed of the drug. The ratio of the two metabolites was lower among black youth, indicating that nicotine/cotinine metabolism was occurring more slowly in this group.

They also measured the ratio of one nicotine breakdown product (cotinine) to the number of cigarettes smoked per day (CPD). Although black youth smoked significantly fewer cigarettes per day — 15.1 cigarettes vs. 19.6 cigarettes for white youth — white and black youth exhibited similar measures of nicotine dependence and blood cotinine concentrations. The significantly higher cotinine-to-CPD ratio among black youth confirmed the slower metabolism among black teens.

“Our findings support the hypothesis that racial and ethnic differences in nicotine metabolism exist among adolescent smokers, with black teens smoking less but being exposed to as much nicotine as white teens,” says Dr. Moolchan.

The findings also suggest that smoking rates may be only one of a number of factors to consider when selecting appropriate treatments for smoking cessation. “An important implication is that black youth may not be offered certain smoking cessation therapies if those treatments are selected largely on the number of cigarettes smoked per day,” says Dr. Volkow. “Thus, we need to look at aspects of nicotine dependence other than consumption to guide the selection of appropriate and effective therapies.”

The study results remained statistically significant after controlling for smoking menthol cigarettes. Recent findings have suggested that menthol might increase the addictiveness of tobacco, and that menthol may play a role in inhibiting nicotine metabolism. Studies also have indicated that blacks show a preference for menthol cigarettes compared to white smokers.