|NIDA Researchers Identify Genetic Variant Linked
to Nicotine Addiction and Lung Cancer
Variant also Increases Risk for Cardiovascular Disease
Scientists have identified a genetic variant that not only makes
smokers more susceptible to nicotine addiction but also increases
their risk of developing two smoking-related diseases, lung cancer
and peripheral arterial disease. The research was supported by
the National Institute on Drug Abuse (NIDA), part of the National
Institutes of Health (NIH).
The study, published in the April 3 issue of the journal Nature, "highlights
the advances that are being made in genetics research, which can
now identify gene variants that increase the risk of complex bio-behavioral
disorders," says NIH Director Dr. Elias Zerhouni. "This
finding will help us in our efforts to further reduce the scope
and devastating consequences of cigarette smoking."
"These results suggest for the first time that a single genetic
variant not only can predispose to nicotine addiction but may also
increase sensitivity to extremely serious smoking-related diseases," explains
NIDA Director Dr. Nora Volkow. "Additionally, it points to
potential targets for new smoking-cessation medications that may
be more effective at helping smokers to quit."
The variant is closely linked to two of the known subunits of
nicotine receptors, the sites on the surface of many cells in the
brain and body that can be bound by nicotine. When nicotine attaches
to these receptors in the brain, there are changes in cell activity
that results in its addictive effects.
Carriers of this genetic variant are more likely than noncarriers
to be heavy smokers, dependent on nicotine, and less likely to
quit smoking. "The variant does not increase the likelihood
that a person will start smoking, but for people who do smoke it
increases the likelihood of addiction," says Dr. Kári
Stefánsson, the study's principal investigator and chief
executive officer of deCODE Genetics, a biopharmaceutical company
based in Reykjavik, Iceland.
The variant was identified through a technique known as genome-wide
association, in which DNA samples (from more than 10,000 Icelandic
smokers) were analyzed for the presence of more than 300,000 genetic
markers. Subsequent investigation showed that carriers of the variant
strongly associated with nicotine dependence were also at increased
risk for two smoking-related diseases, peripheral arterial disease
and lung cancer. The findings were replicated in populations from
five European countries and New Zealand. The researchers estimate
that the variant explains 18 percent of cases of lung cancer and
10 percent of cases of peripheral arterial disease in smokers.
The same variant was identified as one that increased risk for
lung cancer in two articles appearing in the April 3rd, 2008, issue
of Nature Genetics, partially funded by two other NIH
institutes — the National Cancer Institute and the National
Human Genome Research Institute.
For more information on Smoking/Nicotine: http://www.drugabuse.gov/DrugPages/Nicotine.html
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 inform policy and improve 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
web site 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 www.nih.gov.