Previous research analyzing the DNA marker profiles between smokers and non-smokers has shown that certain genetic variants are associated with the number of cigarettes smoked per day, smoking initiation and smoking cessation.
New research suggests that genetics may play a role in helping to determine if a person is likely to kick the nicotine habit on his own or need medication to improve the chances of success, according to findings published today in the American Journal of Psychiatry.
In the study (subscription required), scientists examined data from more than 1,000 smokers in a clinical treatment study and over 5,000 smokers who participated in community-based studies. Researchers focused on the relationship between smokers' ability to quit smoking successfully and genetic variations that have been linked to risk for heavy smoking and nicotine dependence. According to a National Institute of Drug Abuse release:
Researchers focused on specific variations in a cluster of nicotinic receptor genes, CHRNA5-CHRNA3-CHRNB4, which prior studies have shown contribute to nicotine dependence and heavy smoking. Using data obtained from a previous study supported by the National Heart Lung and Blood Institute, researchers showed that individuals carrying the high-risk form of this gene cluster reported a 2-year delay in the median quit age compared to those with the low-risk genes. This delay was attributable to a pattern of heavier smoking among those with the high risk gene cluster. The researchers then conducted a clinical trial, which confirmed that persons with the high-risk genes were more likely to fail in their quit attempts compared to those with the low-risk genes when treated with placebo. However, medications approved for nicotine cessation (such as nicotine replacement therapies or bupropion) increased the likelihood of abstinence in the high risk groups. Those with the highest risk had a three-fold increase in their odds of being abstinent at the end of active treatment compared to placebo, indicating that these medications may be particularly beneficial for this population.
Researchers say the findings will help advance the understanding of genetics and addition and could be useful in developing tailored therapies to increase smoking cessation rates.