London: For some smokers, quitting the habit could be especially difficult because their dependence may be explained in part by genetics, says a new study.
Scientists have identified genetic variants associated with key smoking behaviors that have a significant impact on health.
Helena Furberg, and Patrick Sullivan, from University of North Carolina at Chapel Hill School of Medicine, led the largest genetic study of smoking, called the Tobacco and Genetics Consortium (TAG), collaborating with scientists from 16 large genetic studies worldwide.
They compared the DNA marker profiles between smokers and non-smokers to examine whether genetic variants affect whether people start to smoke.
They also compared the DNA among smokers to see if genetic variants affected the number of cigarettes smoked per day, the age when people began to smoke and whether smokers were able to quit.
The team found that three genetic regions were associated with the number of cigarettes smoked per day, one region was associated with smoking initiation and one variant was associated with smoking cessation.
The variants on chromosome 15 that were associated with heavy smoking lie within a region that contains nicotinic receptor genes, which other scientists have previously associated with nicotine dependence and lung cancer.
“We hope that this work will allow researchers from multiple disciplines to develop a better understanding of the genetics of addiction and evaluate how drug-gene interactions could be used to create and tailor therapies to improve the rates of smoking cessation,” said Furberg.
“More work needs to be done before these findings can be used to treat smokers who wish to quit. At this time, testing for these variants will not tell you anything meaningful about your risk of smoking or nicotine dependence. Of course, all smokers should be encouraged to quit regardless of their genetic make-up,” she added.
The study has been paper in the journal Nature Genetics.