It is arguably the Holy Grail of healthcare - how to persuade more smokers to quit their habit.
Countless scientific evidence has proved an increased risk of various cancers for those who continue to smoke.
And yet, it is estimated almost 10 million people still persist with their deadly habit.
Now, scientists believe they have found a new way of enticing people to pack in their addiction for good.
Paying smokers to quit, and giving them more money the longer they avoid cigarettes could help, a new study suggests.
To test the power of money to combat addiction, researchers in Switzerland offered about 800 low-income smokers pamphlets and online cessation guides.
Half of them were also eligible to receive as much as $1,650 (£1,249) if a series of six lab tests verified they stopped smoking.
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These payments started out at $100 (£75) if lab tests verified participants hadn’t smoked after one week, and gradually increased to $440 (£333) by the time the last test was done at six months.
At six months, 36 per cent of the payment group and about six per cent of the control group had quit smoking.
One year after the payments ended, about 10 per cent of the people eligible for financial incentives remained abstinent, compared with roughly four per cent for the control group.
“Money compensated for the loss of a valued activity (smoking) and increased both the likelihood of making a quit attempt and the likelihood of succeeding when trying to quit,” said lead study author Jean-Francois Etter, a public health researcher at the University of Geneva.
The participants were around 32 years old on average at the start of the study and they had typically started smoking around age 17.
Money increased both the likelihood of making a quit attempt and the likelihood of succeeding when trying to quitJean-Francois Etter
They tended to smoke about 16 cigarettes a day, a little less than a pack.
The scientists tested for carbon monoxide in exhaled air and a byproduct of nicotine in saliva samples to confirm whether participants had quit or continued to smoke.
While many people who quit relapsed after payments ended, abstinence rates at the 18-month mark for the group that received financial motivation were nearly 10 per cent, compared to less than four per cent in the group that didn’t get any money, researchers report in the Journal of the American College of Cardiology.
With a difference of about 6 percentage points between the control and the payments group one year after the money stopped flowing, 17 people would need to go through an incentive program like the one in the study to get one person to quit, the authors note.
Past research has shown that financial incentives can help smokers remain abstinent, particularly among more affluent employed smokers who have access to counselling and other cessation support, Etter said.
“Many interventions based on education (booklets, leaflets, various education strategies) tend to work less well among people with low income and low education, in whom smoking prevalence is particularly high,” Etter said.
Still, the findings suggest that this method would cost about $28,000 (£21,958) a year to get just one additional long-term quitter, Judith Prochaska of Stanford University in California said in an accompanying editorial.
This might limit adoption in the real world.
The appeal of this intervention is its simplicity, Prochaska told Reuters.
“Individuals could create this type of intervention for themselves.” she said. “A pack a day smoker who puts that money aside rather than purchasing cigarettes would save over $2,000 (£1,514) a year – more than the payment provided in the study.”