A new study finds that people with a particular version of a gene involved in the brain’s reward system are more likely to succeed in quitting smoking.
Compared with people who have other versions of this gene, those with the lucky DNA were also more likely to abstain from cigarettes. The study in Translational Psychiatry was a meta-analysis (a review of other studies) and supports a role for heredity, i.e., genotype, in the likelihood that someone will become a smoker and how difficult it will be, once starting to smoke, to eventually quit.
The primary objective was to determine whether the variant DRD2/ANKK1 gene Taq1A has any effect on smoking cessation. ANKK1 happens to be next to the DRD2 gene, which helps the brain recognize dopamine, the chemical that’s produced in the brain to reinforce useful behaviors like eating and having sex. Addictive drugs, including nicotine, also cause dopamine levels to spike.
People inherit either an A1 or A2 version of this gene fragment from each of their parents. That means there are three possible genotypes: two A1s, two A2s or one of each. When it comes to quitting smoking, the helpful type is A2/A2. Those with two A2s had better odds of kicking the habit than those with one or two A1s.
Their literature survey consisted of 9,487 Caucasians (an obvious limitation.) Using statistical and epidemiological techniques, they determined that Taq1A A1/ genotypes were significantly associated with smoking cessation. They found an approximately 22 percent higher rate of smoking cessation among the study subjects with the A2A2 variant in the dopamine receptor gene Taq1A.
It is unclear how many smokers, or how many Americans, carry this particular gene variant. Given the fact that even if one carries this trait, the benefit (in the 22 percent better chance of quitting) is not so large as to confer any reliable hope of getting your genes to help you quit. Fortunately, this is a problem going out of existence and we are proud we have helped for 37 years. CDC data show that the smoking rate for both adults and teens in the U.S. is declining but the dire consequences of smoking make me want to remind everyone that it’s better not to rely on lucky genes – the best way to “quit” is to never start! Once addicted to nicotine and smoking, it is very difficult to quit, whatever your genome.
This study is interesting from a “personalized medicine” point of view and for those studying pharmacogenetics but for the rest of us, let me repeat: the fault (smoking) is in ourselves, not in our stars, nor in our genes.