New research has suggested that smokers who experience greater difficulty quitting or cutting down how much they smoke may have their genes to blame.
Several genes seem to be related to how likely someone is to start smoking and whether they will find it especially difficult to quit. Over the course of three studies involving data collected on 140,000 people, published in the journal Nature Genetics, it became clear that single-letter mutations lie in the region of the DNA molecule that contains genes that influence nicotine addiction.
Of the three genetic mutations pinpointed as being associated with smoking behaviour, two had not been identified before.
Each time a variant was noticed in smokers it seemed to increase by a small amount how many cigarettes they consume, roughly increasing it by half a cigarette a day. The mutations also seemed to increase the risk of the person developing lung cancer.
However the scientists warned that it was not entierely clear how the relationship between smoking behaviour, genetic mutations and lung cancer worked and advised that further research needed to be done to investigate the link.
The research was conducted by the University of North Carolins, Oxford University and the Icelandic group deCODE.