Ina Fassbender/Reuters/Corbis

The controversy over electronic cigarettes has been reignited today with the publication of a study claiming that they do not help smokers to quit their habit.

Whether or not ‘e-cigarettes’ are an effective aid in the cessation of smoking has become a major issue for the rapidly growing industry that produces the devices, and for the tobacco researchers struggling to assess their impact. There is widespread agreement that inhaling from an e-cigarette, where a heating element vapourizes a liquid containing nicotine, is not as harmful as smoking a conventional cigarette, and proponents say that the products could save millions of lives. But some researchers and tobacco-control activists fear that the devices could make tobacco use seem socially acceptable again and may not assist people in actually reducing their addiction.

Pamela Ling, a tobacco researcher at the University of California, San Francisco, and her colleagues followed 949 people who detailed their smoking habits though an online survey, and found that 88 of those who had used e-cigarettes were no more likely to have quit or reduced their smoking after a year than other smokers. “We found that there was no difference in the rate of quitting between smokers who used an e-cigarette and those who did not”, even after controlling for factors such as the user's dependence on tobacco, Ling told Nature in an e-mail.

She added: “Advertising suggesting that e-cigarettes are effective for smoking cessation should be prohibited until such claims are supported by scientific evidence.” Her team reports the results today in JAMA Internal Medicine1.

Smokers' saviour?

Peter Hajek, director of the Tobacco Dependence Research Unit at the Barts and The London School of Medicine and Dentistry, says that many researchers think e-cigarettes represent “the best hope so far to put a stop to smoking-related death and disease by replacing deadly cigarettes with a safer alternative”.

Hajek says that the new paper shows only that e-cigarettes appeal to smokers who are heavily dependent on tobacco. The same results would be obtained if the survey looked at smokers who try nicotine-replacement treatments, he says, and the results have no bearing at all on whether e-cigarettes are or are not an effective method of smoking cessation. The conclusions the authors of the paper draw are “just not related in any way to the study finding", says Hajek.

The regulation of e-cigarettes is a hugely debated area. Some scientists want the products regulated as medical devices, which would mean that they would be subject to tough quality controls and limits on advertising, and that their manufacturers would have to supply evidence to back up claims made for their products, such as the ability to aid smoking cessation. Both the United States and the United Kingdom are currently considering such regulation.

But other scientists say that such heavy regulation could kill the nascent industry, or leave it in the hands of the big tobacco companies, which have the deep pockets necessary to comply with such regulations.

Vaughan Rees, deputy director of the Center for Global Tobacco Control at the Harvard School of Public Health in Boston, Massachusetts, says that many existing e-cigarettes do not deliver enough nicotine to support total switching from conventional cigarettes. He adds that the study “provides an important addition to the growing body of research suggesting that e-cigarettes are not particularly good at promoting quitting”.

“The public should be educated about the limits of e-cigarettes to support cessation,” he said in an e-mail.

