Smokers who are paid to quit succeed far more often than those who get no cash reward, according to a new study that provides some of the strongest evidence yet that financial incentives can help change such behavior.

The study, one of the largest of its kind, comes at a time when more employers, schools and other institutions are paying people to do everything from lose weight to improve their grades. The latest findings were published in this week's New England Journal of Medicine.

Smoking is one of the nation's biggest causes of premature death. It is believed to kill about 480,000 Americans a year. About 20% of all U.S. adults smoke, which is down from about 25% 10 years ago. Although most smokers say they want to quit, research in recent years indicates that less than 3% of those who try every year succeed in doing so permanently.

For the new study, researchers, led by a team from the University of Pennsylvania, tracked 878 General Electric Co. employees from around the country for a year and a half in 2005 and 2006. Participants, who smoked an average of one pack of cigarettes a day, were divided into two groups of roughly equal size. All received information about smoking-cessation programs.

Members of one group also got as much as $750 in cash, with the payments spread out over time to encourage longer-term abstinence. Those participants got $100 for completing a smoking-cessation program, $250 if they stopped smoking within six months after enrolling in the study, and $400 for continuing to abstain from smoking for an additional six months.

All participants were contacted three months after they enrolled in the study and periodically after that. Those who said they had stopped smoking at any point during the study were asked to submit saliva or urine samples for testing so that their claims could be verified.

About 14.7% of the group offered financial incentives said they had stopped smoking within the first year of the study, compared with 5% of the other group. At the time of their last interview for the 18-month study, 9.4% of the paid group was still abstaining compared with 3.6% of those who got no money.

Smoking experts say previous studies have found little clear evidence that such financial incentives help in getting smokers to quit, although most have involved far fewer patients and much smaller incentives.

The study 'shows that incentives work,' said Steven Schroeder, director of the Smoking Cessation Leadership Center at the University of California, San Francisco, who wasn't involved with the research. Helen Darling, president of the National Business Group on Health, a professional organization, said the findings give employers solid evidence that such incentives can help them save money on health-care costs for employees. 'You'd prefer not to pay them, but it's worth it,' she said.

一項最新研究顯示，拿了錢戒煙的成功率要遠遠超過那些沒錢拿的，這是財務激勵有助于改變吸煙行為的一項最有力的證據。

在同類項目中規模最大的這項研究推出之際，正值當今越來越多的雇主、學校和其他機構花錢鼓勵人們做從減肥到提高分數的各種事情。這項最新研究發表在上周的《新英格蘭醫學雜志》(New England Journal of Medicine)上。

吸煙是美國人最大的早逝原因之一。據稱美國每年大約有48萬人死于吸煙。目前美國成年人大約有五分之一吸煙，這個比例低于十年前的四分之一。盡管大多數吸煙者表示自己愿意戒煙，但近年來的研究顯示，每年都嘗試戒煙的人只有不到3%完全戒除了煙癮。

從2005年到2006年的一年半時間，賓夕法尼亞州大學的一個研究小組對通用電氣(General Electric Co.)分布在美國各地的878名員工進行了此項研究。這些研究對象平均每天吸一包煙，他們被分成人數相當的兩個小組。所有人都被告知了這個戒煙項目的有關信息。

其中一個小組的研究對象可以拿到總計750美元的現金；這筆錢分步發放，以鼓勵研究對象更長期的遠離煙癮。這些研究對象完成一個戒煙項目后就可以拿到100美元，登記參加研究之后六個月內不再復吸還可以得到250美元，再堅持六個月不 煙就能收獲400美元的獎金。

在登記參加研究之后三個月，研究人員聯絡了所有研究對象，并在此后定期回訪。那些表示研究過程中一直沒吸煙的人會被要求提交唾液或尿液樣本用于測試，以便驗證他們自述是否屬實。

提供獎金的小組中，大約有14.7%的人說他們在研究期間的頭一年內沒有吸煙，這個比例高于另外一組的5%。在為期18個月的此次研究最后一次回訪中，付費戒煙小組有9.4%人仍然沒有吸煙，而另外一個小組這個比例僅有3.6%。

戒煙問題專家表示，此前的研究沒有發現明顯證據表明此類財務激勵有助于幫助吸煙者戒煙，不過，大多數此類研究的參加人數和獎金額都要少的多。

加州大學舊金山分校的戒煙領導中心(Smoking Cessation Leadership Center)主任施羅德(Steven Schroeder)說，這項研究顯示了激勵能發揮作用。他沒有參與這項研究。美國企業員工健康組織(National Business Group on Health)主席達林(Helen Darling)表示，研究結果為雇主們提供了有力證據，表明此類激勵能幫助它們減少對員工的醫療成本。她說，你當然更希望不付錢，但這么做值得。