Genetic Variations Influence Nicotine Addiction For Young Smokers
July 07, 2017
A
group of common genetics variants that affect the nicotine receptors in
the nervous system could significantly increase the risk of developing
nicotine addiction. These results, which could have powerful
implications for policy preventing tobacco use in young people, were
published on July 11, 2008 in the open-access journal PLoS
Genetics.
Single
nucleotide polymorphisms (SNPs) are variations in the genetic sequence
that involve a single unit of DNA. A haplotype is a set of SNPs that
are often linked together.
To study the effects of various
haplotypes on nicotine addiction, the researchers, from the University
of Utah and the University of Wisconsin, examined 2,827 long-term
European American smokers in Utah and Wisconsin in the National Heart,
Lung, and Blood Institute's Lung Health Study. The level of nicotine
dependence for each subject was evaluated, along with the age they
began smoking daily, the number of years they smoked, and the average
number of cigarettes each smoked daily. Additionally, DNA samples were
collected from all smokers, and the occurrence of several common SNPs,
which had already been grouped into haplotypes,which had been
previously identified in a subset of the participants.
One
haplotype related to the nicotine receptor in neurons put European
American smokers at a greater risk of heavy nicotine dependence as
adults if they began smoking daily before reaching 17 years.
Specifically, people who began smoking before 17 years with two copies
of this haplotype had between a 1.6- and 5-fold increase in risk of
heavy smoking as an adult. This haplotype did not significantly
increase the risk of addiction in adulthood for those who began smoking
daily after reaching 17 years. A second haplotype instead reduced the
risk of heavy nicotine dependence as an adult for those one smoked as a
youth.
This genetic influence is likely valid despite the
possible confounding ethnicity of the addicted smokers. According to
lead author Robert Weiss, Ph.D., professor
of human genetics at the University of Utah, says: "We know that people
who begin smoking at a young age are
more likely to face severe nicotine dependence later in life. This
finding suggests that genetic influences expressed during adolescence
contribute to the risk of lifetime addiction severity produced from the
early onset of tobacco use."
According
to Dr. Nora Volkow, Director of the National Institute on Drug Abuse
(NIDA), points out that this is an important study investigating the
interactions of genetic factors with individual behaviors. "This
study adds to recent advances in understanding how genetic variation
can affect susceptibility to nicotine addiction, success or failure of
smoking
cessation treatments, and the risk of disease associated with tobacco
use," she says. "As we learn more about how both genes and environment
play a role in
smoking, we will be able to better tailor both prevention and cessation
programs to individuals."
A Candidate Gene Approach Identifies the CHRNA5-A3-B4 Region
as a Risk Factor for Age-Dependent Nicotine Addiction.
Weiss RB, Baker TB, Cannon DS, von Niederhausern A, Dunn DM, et al.
PLoS Genet 4(7): e1000125.
doi:10.1371/journal.pgen.1000125
Click
Here For Full Length Article
Anna Sophia McKenney