In the genes: Why some women find it so hard to quit smoking PARIS: Tiny genetic differences among women make it far easier for some to give up smoking using nicotine patches, according to a study published online Friday by the British Medical Journal (BMJ).
Women who have variations of a gene that controls dopamine, a chemical that is critical for the sensation of reward, are twice as likely to stub out smoking compared with counterparts who do not have this variant.
The Oxford University study monitored a large group of men and women, heavy smokers who puffed on at least 15 cigarettes a day.
They carried out biochemical tests -- measuring carbon monoxide concentrations in their breath and saliva levels of cotinine, a trace chemical from smoking -- to confirm whether they had quit or not.
The volunteers either got nicotine patches over 12 weeks or dummy lookalike patch and were monitored a week, three months, half a year, a year and then eight years after the programme.
At the eight-year stage, they also gave blood samples, which were scanned for a gene called DRD2 32806, to see whether it contained two minor variants, CT or TT, or the more common variant, CC.
Forty-one percent of the recruits, men or women, had the CT or TT genotypes, and the rest had CC.
Women with the CC variant who took the patches were nearly half as successful in stopping smoking, and staying off tobacco, compared with women with the less common CT or TT variants.
But there was no difference at all in the success rate among men.
The findings are important, because they prove that, besides willpower, genes and gender can play a big factor in whether nicotine patches will work or not.
The gene in question controls the brain's uptake of dopamine, a substance that plays a role in the chemical cascade that leads to the sensation of pleasure.
The nicotine replacement therapy took place in 1991-2 and involved 1,625 participants.
Eight years later, 1,532 were still alive, of whom 752 gave a blood sample.
According to a study published in The Lancet last September, smoking kills around five million people a year, with female smokers and smokers in the developing countries the most vulnerable group. - AFP
Yup. In my mind, I always think that smokers are pretty rich.