The recent rise in electronic cigarette use among adult smokers has been associated with a significant increase in smoking cessation, according to researchers in the US.
They said their study was based on the largest representative sample of e-cigarette users to date and provided a strong case that the devices had helped drive smoking cessation at population level.
“This analysis presents a strong case that e-cigarette use played an important role”
The findings add to the public health debate regarding the relative merits and potential drawbacks of the devices. At present, the scientific community has appeared divided on whether to back e-cigarettes.
Some suggest they will cut smoking rates by acting as a nicotine replacement therapy, while others argue that they could reduce the urgency to quit and continue to normalise the physical act of smoking. Long-term data is also lacking on their side effects and impact.
The researchers, led by Professor Shu-Hong Zhu at the University of California, examined whether the rise in use of e-cigarettes in the US was linked to a change in the overall smoking cessation rate, based on analysis of five population surveys carried out during 2001-15.
Of 161,054 respondents to the 2014-15 survey, 22,548 were current smokers and 2,136 recent quitters. Among them, 38.2% of current smokers and 49.3% of recent quitters had tried e-cigarettes.
The results showed that e-cigarette users were more likely than non-users to make a quit attempt – 65% versus 40% – and more likely to succeed in quitting for at least three months – 8.2% versus 4.8%.
The overall population quit rate for 2014-15 was significantly higher than that for 2010-11, up from 4.5% to 5.6%, and higher than those for all other survey years.
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Although the 1.1 percentage point increase in cessation rate might appear small, the researchers highlighted that it represented around 350,000 additional US smokers who quit during 2014-15.
The researchers highlighted that the study had two key findings. Firstly, in 2014-15, e-cigarette users attempted to quit cigarette smoking and succeeded in quitting smoking at higher rates than non-users. Secondly, the overall cessation rate in 2014-15 rose significantly from that of 2010-11.
“Other interventions that occurred concurrently, such as a national campaign showing evocative ads that highlight the serious health consequences of tobacco use, most likely played a role in increasing the cessation rate,” said the researchers in the British Medical Journal.
“But this analysis presents a strong case that e-cigarette use also played an important role,” they said. “These findings need to be weighed carefully in regulatory policy making and in the planning of tobacco control interventions.”
In an accompanying editorial in the same journal, Christopher Bullen, professor of public health at the University of Auckland in New Zealand, also said the new study raised important points for public health policy, especially in countries that were considering restricting the use of e-cigarettes.
“In light of this evidence, policymakers in countries contemplating a more restrictive approach to the regulation of e-cigarettes should pause to consider if pursuing such a course of action is the right thing to do for population health,” he said.
In contrast, a Scottish study has suggested teenagers who have tried an e-cigarette may be more likely to go on to smoke cigarettes compared with those who have not.
“Further research is required to discover how experimentation with e-cigarettes might influence attitudes to smoking in young people”
The study, published today in the journal Tobacco Control, found a link between e-cigarette use in “never smokers” and their subsequent first experimentation with cigarettes in the following year.
The research, conducted by a collaboration between the universities of Stirling, St Andrews and Edinburgh, and ScotCen, focused on pupils at four secondary schools. Young people aged between 11 and 18 years old were surveyed in February-March 2015 and then again 12 months later.
The 2016 survey found that 40.4% of those who had tried an e-cigarette in the initial 2015 survey went on to smoke a cigarette in the following 12 months, compared to only 12.8% of young people who had not tried an e-cigarette.
Stuy author Sally Haw, professor of public and population health at Stirling University, said: “The greater impact of e-cigarette use on young people thought to be at lower risk of starting smoking is of particular concern. Further research is required to discover how experimentation with e-cigarettes might influence attitudes to smoking in young people traditionally at lower risk of becoming smokers.”
In its new tobacco control plan, published earlier this month, the UK government acknowledged that e-cigarettes were the “most popular quitting method” and, alongside local stop smoking services, could have high success rates.
The plan said Public Health England would support the provision of training on evidence-based interventions that support quitting, including e-cigarettes or other nicotine delivery systems.
The body would regularly update its evidence base on e-cigarettes and include the advice in all quit smoking campaign messaging, added the plan, it said.
An expert review, published by Public Health England in 2015, said e-cigarettes were significantly less harmful to health than tobacco and had the potential to be a “game changer” in helping smokers quit.
Meanwhile, UK researchers said earlier this year that e-cigarettes were less toxic and safer to use than conventional cigarettes.
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They found people who swapped smoking regular cigarettes for e-cigarettes or nicotine replacement therapy for at least six months had much lower levels of cancer causing substances than smokers.