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Genetics May Personalize Quit-Smoking Methods

Study Shows Genetic Profile May Help Smokers Individualize Their Smoking-Cessation Therapy

By Denise Mann
WebMD Health News

Reviewed By Louise Chang, MD

July 7, 2010 -- A new, personalized approach to quitting smoking may one day help boost success rates by taking some of the guesswork out of matching smokers with available tools.

New research in the July-August issue of Molecular Medicine shows that your genetic profile combined with your level of nicotine dependence can help guide treatment decisions and maximize your chances of kicking the habit for good.

As any former smoker or wannabe former smoker can attest, quitting smoking is not easy. Fully 70% of 46 million U.S. smokers say they want to kick the habit, yet less than 5% who try to do so cold turkey are successful after a year. When a smoker uses available smoking-cessation tools such as nicotine patches, gum, inhalers, or medications, their success rate can increase to less than 25%.

"There are nicotine replacement therapies such as gum, patches, lozenges, and prescription aids, but there is very little guidance as to which is best and for whom," says study researcher Jed E. Rose, PhD, director of the Duke Center for Nicotine and Smoking Cessation Research in Durham, N.C. "Different treatments will work differently for different smokers, and this is the first step toward being able to predict which treatments would be more successful in which smokers."

Scanning for Genetic Markers

The researchers scanned 520,000 genetic blood markers of smokers participating in several studies. Using this genetic information, they created a "quit success score" or a number that can be combined with a smoker's level of nicotine dependence to help predict whether a 42-miiligram/24-hour nicotine patch or a 21-milligram/24-hour nicotine patch is best suited. Nicotine dependence was assessed via questionnaire.

They tested this on 479 smokers with at least a half-a-pack-a-day habit who wanted to quit. Participants were categorized as having a high or low dependence on nicotine. Individuals with a high dependence and low "quit scores" based on their genetic profile did better with the high-dose patch, the study showed. By comparison, individuals with a low dependence on nicotine can quit using the lower-dose patch.

"People who were highly dependent on nicotine and had a certain genotype did better on the higher-dose patch," Rose says.

The next step is to expand the work and see how -- and in whom -- prescription smoking-cessation medications such as Chantix and Zyban fit in.

In the future, "all of the available aids could be brought into an algorithm that could determine what combination or individual modality would be best by using genetic information and other characteristics of smoking behavior," he says.

It is not one gene that says this smoker will do better with this smoking cessation tool, but a group of genes that when taken together help better guide treatment decisions, explains study co-researcher George Uhl, MD, PhD, chief of molecular neurobiology research at National Institute on Drug Abuse in Baltimore.

"Some people have an easier time quitting than others, and this one set of markers helps to match people with the right medication," he says.

"The individual differences in the ability to quit smoking are half genetic," he says. "There are several behavioral and pharmacological smoking-cessation tools that are each effective, but none are totally effective [and] it would be nice to know which [genetic] variants are selective for behavioral or medical approaches or both," he says.

Matching the Medication to the Individual

Scott McIntosh, PhD, director of the Greater Rochester Area Tobacco Cessation Center and an associate professor of community and preventive medicine at University of Rochester Medical Center, is all for this new, individualized approach to smoking cessation.

"This is an excellent direction to go in because you can tailor quit attempts by making sure that you have the best medication for that person," he says.

There may be other genetic markers that can help point smokers toward the most effective therapies, he says.

For example, "someone who is very social might do better with a telephone quit line or group counseling, whereas someone who is not as social may do better if they just received information on how to quit," he says.

"There will be genetic markers for that sort of thing," McIntosh predicts. "There is no one-size-fits-all approach to smoking cessation, and this type of treatment matching can help physicians further tailor their approach," he says.

SOURCES: Rose, J.E. Molecular Medicine, July-August 2010; vol 16: pp 247-253.

Jed E. Rose, PhD, director, Duke Center for Nicotine and Smoking Cessation Research, Durham, N.C.

George Uhl, MD, PhD, chief, molecular neurobiology research, National Institute on Drug Abuse, Baltimore.

Scott McIntosh, PhD, director, Greater Rochester Area Tobacco Cessation Center, N.Y.

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