Having a particular gene may make it harder for some people to quit smoking, new research suggests today.
Scientists found that individuals with the abnormality tend not to be heavy smokers but seem to find it especially difficult to give up the habit. However, the same gene appears to protect against emphysema, a serious smoking-related illness.
The trait, known as CYP2A6del, is a defective version of a gene which assists breakdown of nicotine in the body. Previous research had suggested genetic differences related to nicotine metabolism between individuals.
Scientists in Japan took DNA from 203 current or ex-smokers with suspected chronic obstructive pulmonary disease (COPD) and compared it with DNA from 123 healthy volunteers.
COPD is a combination of chronic bronchitis and emphysema that causes persistent disruption of air flow in and out of the lungs.
The researchers noted the number of cigarettes participants smoked per day, and the length of time they had smoked. Those who had quit were asked how long it had been since they had a cigarette.
The findings, published in the journal Thorax, showed that people with the CYP2A6del version of the gene were significantly more likely to be current than ex-smokers.
A possible explanation was that the mutant gene held back the normal breakdown of nicotine, allowing its addictive effects to last longer.
PA