Dr. Scott Lee, an associate professor of medicine at the Vanderbilt University Medical Center, talks about how quitting smoking could be harder for others depending on their genes.
Interview conducted by Ivanhoe Broadcast News in 2023.
What part does genetics play in the metabolism of nicotine?
Lee: Smoking has a strong genetic basis. Studies have shown that roughly 50% of the probability to start smoking is actually determined by genetics. One factor that keeps people smoking is the rate at which someone metabolizes nicotine, which is also genetically-based. Faster metabolizers tend to have more trouble quitting smoking and also tend to smoke more. That is an issue that we tried to address in this study.
What do you mean by metabolized?
Lee: What happens biochemically when someone smokes a cigarette is that the nicotine is absorbed through the lungs and it very quickly goes to the brain, which provides the pleasant effects of nicotine and the addictive effects. However, it also very quickly goes to the liver where an enzyme called CYP2A6 metabolizes nicotine, in other words, it changes the nicotine molecules so that it’s inactive and eventually excreted through the urine.
What makes people quit smoking?
Lee: There are a lot of reasons that people quit smoking, but nicotine is highly addictive. How it works is that it very quickly goes to the brain and actually attaches to receptors in the reward center of the brain, and so smoking a cigarette provides a lot of satisfaction due to the nature of nicotine.
What additional protocols are in place for faster metabolizing smokers?
Lee: In this study, we try to see whether providing more support to smokers as they leave the hospital might improve their quit rates. We provided enhanced support to both the fast and slow metabolizers, and that included free nicotine replacement therapy when they were leaving the hospital. Also, a counselor was provided who was available to give coaching and support over the first three months after leaving the hospital.
Are the fast metabolizers having to smoke more to get a huge rush of nicotine? Is that why they aren’t successful in quitting?
Lee: It’s been found that there are multiple reasons why fast metabolizers have more trouble quitting. Some of them include the more rapid nicotine clearance. They also tend to have more of the nicotine receptors in the brain, and so the brain is hungrier for nicotine than the case for slower metabolizers. And also there are other neural reasons why fast metabolizers have trouble quitting, such as the fact that just even looking at a cigarette provides more of a dopamine hit to fast metabolizers than slow metabolizers.
What are the different forms of smoking cessation treatment?
Lee: Broadly speaking, there are two main approaches to treating smoking or facilitating smoking cessation. Pharmacotherapy (medications) and behavioral therapy. Pharmacotherapy includes Nicotine replacement therapy, a medication called Varenicline, as well as a medication called Bupropion. Behavioral therapy consists of counseling, coaching, and providing emotional and psychological support to the person who’s trying to quit smoking.
Did the fast metabolizers respond well to the smoking cessation treatment?
Lee: What we found in this study is that providing more behavioral support to fast metabolizers increase their quit rates. Those who didn’t get that enhanced support quit at a rate of around 10% by six months, whereas providing additional support increased that quit rate to 17%. That’s a 70% improvement which is pretty significant when it comes to smoking cessation.
Is there anything else you’d like to cover regarding this topic?
Lee: Until now, treating smoking has been a one-size fits all approach. But now that we’re starting to understand that genetics shapes parts of smoking, such as starting smoking and quitting smoking, we’re on the precipice of a new approach to treating smoking that takes account genetic factors like the rate at which someone metabolizes nicotine. Our study we feel is one contribution to this new personalized approach to smoking cessation.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
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