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 metabolise 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.
"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. The current findings, among the first on adolescent nicotine metabolism, reveal that these differences are in effect during the teen years, as well," says NIDA director Dr. Nora D. Volkow.
"Because nicotine plays an active role in smoking reinforcement, these variations may influence early onset addiction to tobacco. 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," added Dr. Volkow.
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, states a NIH release.
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," said 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, Thus, we need to look at aspects of nicotine dependence other than consumption to guide the selection of appropriate and effective therapies," said Dr. Volkow.
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.
The National Institute on Drug Abuse is a component of the National Institutes of Health, US Department of Health and Human Services. NIDA supports most of the world's research on the health aspects of drug abuse and addiction. The institute carries out a large variety of programmes to ensure the rapid dissemination of research information and its implementation in policy and practice.