[Cevdopagem] Black, white teens show differences in nicotine metabolism

Andréa Ramirez aramirez em fmu.br
Sexta Janeiro 20 18:38:19 BRST 2006

Se o metabolismo da nicotina (cotinina) varia assim em humanos, imaginem a
variação metabólica das outras drogas proibidas... De volta à questão:
como punir os atletas tendo como prova o velho exame de urina, não é
Sabino?  ;-) Abs, Andréa.

U.S. Department of Health and Human Services
NIH News
National Institute on Drug Abuse (NIDA)

EMBARGOED FOR RELEASE: Friday, January 20, 2006; 12:00 a.m. ET

CONTACT: Sara Rosario Wilson, 301-443-6245, media em nida.nih.gov; Contacto
en Español: 301-594-6145


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

"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

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, U.S. 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 programs to
ensure the rapid dissemination of research information and its
implementation in policy and practice. Fact sheets on the health effects
of drugs of abuse and information on NIDA research and other activities
can be found on the NIDA home page at http://www.drugabuse.gov.

The National Institutes of Health (NIH) -- "The Nation's Medical Research
Agency" -- includes 27 Institutes and Centers and is a component of the U.
S. Department of Health and Human Services. It is the primary Federal
agency for conducting and supporting basic, clinical, and translational
medical research, and it investigates the causes, treatments, and cures
for both common and rare diseases. For more information about NIH and its
programs, visit http://www.nih.gov.

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