New Frontiers
in Tobacco Research
Twin studies indicate
that approximately
40–70 percent of
a person’s risk of
becoming addicted
to nicotine depends
on his or her genes.
If so many smokers want to quit,
why are few able to do so successfully?
To address this question,
scientists are increasingly focusing
on the powerful role of genetics in
addiction. Twin studies indicate
that approximately 40–70 percent
of a person’s risk of becoming
addicted to nicotine depends on
his or her genes. Although complex
diseases like addiction involve large
numbers of genes interacting with
a wide variety of environmental
factors, the contribution of a
particular gene can be substantial:
Genetic variants associated with
nicotine metabolism, for example,
have been shown to influence
how people smoke such that slow
metabolizers smoke fewer cigarettes
per day and have a higher
likelihood of quitting, and that
there is greater abstinence among
individuals receiving nicotine
patch therapy. A recent NIDA-funded
study identified a variant
in the gene for a nicotinic receptor
subunit that doubled the risk for
nicotine addiction among smokers.
A subsequent study found that this
gene variant also increased susceptibility
to the severe health consequences
of smoking, including
lung cancer and peripheral arterial
disease. NIDA is currently supporting
large-scale genome-wide association
studies to uncover additional
genetic risk factors in order to better
understand tobacco addiction
and its adverse effects on health.
In addition to predicting an
individual’s risk for nicotine
addiction, genetic markers can
also help predict whether medications
(like bupropion) will effectively
help a smoker quit. This
takes root in the emerging field
of pharmacogenomics, which
investigates how genes influence
a patient’s response to drugs and
medications. In the future, genetic
screening could help clinicians
select treatments, adjust dosages,
and avoid or minimize adverse
reactions, tailoring smoking cessation
therapies to an individual’s
unique genetic inheritance.
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