Popularity of vaping linked to "significant" rise in smokers quitting the habit
The soaring popularity of vaping has been linked to a sharp rise in smokers quitting the habit.
The recent rise in e-cigarette use among adult smokers is associated with a "significant increase" in the number stubbing out smoking, according to a study published in The BMJ.
Researchers say the findings of the American study, based on the largest representative sample of e-cigarette users to date, provides a "strong case" that they have helped to increase the number of people quitting smoking.
Currently, the scientific community is divided over whether e-cigs are an aid to quitting smoking.
Some suggest that they will have a positive impact on smoking rates by acting as a nicotine replacement therapy.
But others argue that they could reduce the urgency to quit smoking.
A team of researchers, led by Professor Shu-Hong Zhu at the University of California, set out to examine whether the increase in use of e-cigarettes in the US, was associated with a change in overall rates of people quitting smoking.
They based their findings on five population surveys dating from 2001 to 2015.
E-cigarette users were identified from the most recent survey (2014-15) and smoking cessation rates were obtained from those who reported smoking cigarettes 12 months before the survey. Rates from this survey were then compared to four earlier surveys.
Of 161,054 respondents to the 2014-15 survey, 22,548 were current smokers and 2,136 recent quitters. Among them, 38.2 per cent of current smokers and 49.3 per cent of recent quitters had tried e-cigarettes.
The results show that vapers (65 per cent) were more likely than non e-cig users (40 per cent) to make an attempt to quit, and more likely to succeed in quitting for at least three months (8.2 per cent v 4.8 per cent).
The overall population quit rate for 2014-15 was "significantly higher" - from 4.5 per cent to 5.6 per cent - than that for 2010-11, and higher than those for all other survey years.
Although the 1.1 percentage point increase in cessation rate might appear small, the researchers pointed out that it represents around 350,000 additional smokers who quit in 2014-15.
They said the study has two key findings. First, 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 smoking cessation rate in 2014-15 increased "significantly" from that of 2010-11.
Prof Zhu said: "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.
"But this analysis presents a strong case that e-cigarette use also played an important role."
He added: "These findings need to be weighed carefully in regulatory policy making and in the planning of tobacco control interventions."
In an accompanying editorial, Christopher Bullen, Professor of Public Health at the University of Auckland in New Zealand, says this study raises important points.
He questioned whether other tobacco control interventions operating at the same time may have been key triggers to the observed step change.
But he said the findings of the American study "mount a convincing case for why the two most likely candidates - a large federal tobacco tax increase in 2009 and a nationwide mass media campaign - could not be stand-alone reasons for the change in cessation rates."
Prof Bullen also pointed out that the figures came from populations in countries with liberal regulatory approaches towards e-cigarettes, enabling substantial numbers of smokers to make the transition away from smoking.
He added: "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."