Shu-Hong Zhu , professor 1 2, Yue-Lin Zhuang , senior statistician 2, Shiushing Wong , senior statistician 2, Sharon E Cummins , assistant professor 1 2, Gary J Tedeschi , clinical director 2 1Department of Family Medicine and Public Health, University of California, San Diego, 9500 Gilman Drive MC 0905, La Jolla, CA 92093-0905, USA 2Moores Cancer Center, University of California, San Diego, CA, USA Correspondence to: S-H Zhu szhu{at}ucsd.edu Accepted 4 July 2017

Abstract Objective To examine whether the increase in use of electronic cigarettes in the USA, which became noticeable around 2010 and increased dramatically by 2014, was associated with a change in overall smoking cessation rate at the population level. E-cigarette users were more likely than non-users to attempt to quit smoking, 65.1% v 40.1% (change=25.0%, 95% confidence interval 23.2% to 26.9%), and more likely to succeed in quitting, 8.2% v 4.8% (3.5%, 2.5% to 4.5%). The BMJ study, titled "E-cigarette use and associated changes in population smoking cessation: evidence from US current population surveys" was undertaken to find whether the dramatic increase in vaping between 2010-2014 had any connection with an overall drop in smoking in the US. "It is remarkable, considering that this is the kind of data pattern that has been predicted but not observed at the population level for cessation medication, such as nicotine replacement therapy and varenicline....These findings need to be weighed carefully in regulatory policy making and in the planning of tobacco control interventions." That correlation is reinforced by the researchers' subgroup analysis of the 2014-15 data, which found that 65 percent of smokers who had used e-cigarettes in the previous year had tried quitting, compared to 40 percent of the other smokers. These are battery-powered, usually contain liquid nicotine, and produce vapor instead of smoke.” Current users of e-cigarettes were ever users who answered “every day” or “some days” to the question: “Do you now use an e-cigarette every day, some days, or not at all?” Those who answered “not at all” were asked when they stopped using e-cigarettes. 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. In a study published in the BMJ British medical journal, scientists from California said their findings were based on the largest representative sample of e-cigarette users to date and provided a "strong case" that e-cigarettes have helped to increase rates of smoking cessation.
A new study, published in the The BMJ medical journal, finds that electronic cigarettes may help smokers stop their habit. The researchers found that a substantial increase in e-cigarette use among American adult smokers was associated with a statistically significant increase in the smoking cessation rate.