Gene influences ability to quit smoking

A gene involved in the brain's reward system has been found to affect people's ability to quit smoking, according to a new study.

Researchers from Zhejiang University, China, and the University of Virginia, Charlottesville, analysed genetic data from 22 studies published between 1994 and 2014, involving 11,151 current and former smokers. They looked at variants in the gene DRD2/ANKK1, which regulates the brain-signalling chemical dopamine, and found that smokers who carried the variation A2/A2 of the SNP, single nucleotide polymorphism,Taq1A had an easier time quitting smoking than those who did not.

'This variant has been studied for years, but this study provided more convincing evidence on the role of this genetic variant in smoking cessation,' Professor Ming Li from the University of Virginia told WebMD.

The benefits of the A2/A2 genetic variant could only be established in a large population of Caucasians. There was no association found among people of East Asian ancestry who had the variant, while African or Mexican smokers were excluded as the authors did not have enough data.

Previous research has tried to associate smoking and the Taq1A polymorphism. It is thought that the link is due to the gene's effect on nicotine addiction.

Professor Li's team cautioned that 'research on this problem remains in its infancy'. 'There are many genetic factors involved in smoking addiction,' he said. 'The variant studied in this report is just one of those.'

Professor Norman Edelman of the State University of New York at Stony Brook, who was not involved in the study, told WebMD: 'There's a huge variability in the ability to quit smoking. Quitting cold turkey, for example, is only effective 5 percent of the time.

'The next step, in terms of advancing the science of smoking cessation, is trying to figure out exactly what the gene does, what proteins it codes for, and to see if there's some way to modify the way it works. That's probably going to turn out to be very hard.'

Although further research is needed to examine this link, the authors say that the findings could potentially be used to develop personalised treatments and medicines to help smokers quit, based on their individual genetic profile.