A study led by Boston University School of Public Health (BUSPH) researchers reports that electronic cigarettes are a promising tool to help smokers quit, producing six-month abstinence（节制） rates nearly double those for traditional nicotine replacement products. In a study published online ahead of print in the American Journal of Preventive Medicine, researchers found that 31 percent of respondents reported having quit smoking six months after first purchasing an electronic cigarette, a battery-powered device providing tobacco-less doses of nicotine in a vaporized（蒸发） solution. The average six-month abstinence rate for traditional nicotine replacement products, such as nicotine patches or gum, is between 12 and 18 percent.

"This study suggests that electronic cigarettes are helping thousands of ex-smokers remain off cigarettes," said lead author Michael Siegel, professor of community health sciences.

The researchers conducted an online survey of 222 first-time purchasers of electronic cigarettes, also known as e-cigarettes, from a leading electronic cigarette distributor. Of those who were not smoking at six months, 34.3 percent reported not using electronic cigarettes or any nicotine-containing products. Almost 67 percent of respondents reported having reduced the number of cigarettes they smoked after using electronic cigarettes.

The study's main limitation is the low response rate of 4.5 percent. It is possible that those who responded to the survey were more likely to have quit smoking than those who did not respond. Nevertheless, despite this limitation, the study authors believe that this is the best evidence to date on the effectiveness of electronic cigarettes for smoking cessation.

They point out that this is the first survey that relied upon an unbiased（公正的） sampling frame.

Despite the limitation, the authors conclude that electronic cigarettes "hold promise as a smoking-cessation method and that they are worthy of further study using more rigorous research designs."

While more study needs to be done on the actual mechanisms of what apparently makes electronic cigarettes effective, Siegel said he believes there might be a link between the e-cigarette's physical simulation of smoking with the success of quitting.

"While it is well-recognized that nicotine plays a role in smoking addiction, little attention has been given to the behavioral aspects of the addiction," he said. "These devices simulate the smoking experience, which appears to make them effective as a smoking cessation（停止，中止） tool."

Electronic cigarettes have proven controversial since coming onto the market more than three years ago. A number of anti-smoking groups have argued that e-cigarettes should not be sold because they have not been shown to be effective for smoking cessation, and several states – including New York – are considering banning e-cigarettes altogether.

"Banning this product would invariably（总是，不变地） result in many ex-smokers returning to cigarette smoking," Siegel said. "Removing electronic cigarettes from the market would substantially harm the public's health."

The study was co-authored by Kerry L. Tanwar and Kathleen S. Wood, also of Boston University School of Public Health.