A noticeable increase in the use of e-cigarettes was accompanied by a significant increase in quit rates at population level, a study from the USA has found.

The researchers analysed data from the US Current Population Survey-Tobacco Use Supplement surveys for the periods 2001-02, 2003, 2006-07, 2010-11, and 2014-15. These surveys covered large and representative population samples and provided information on self-reported smoking prevalence, quit attempts and successful quit attempts, together with data on the use of e-cigarettes. All data were controlled for age, gender, ethnic origin and state of residence.

Of the 161,054 respondents to the 2014-15 survey, 104,788 had never smoked, 22,548 were current smokers and 2,136 were recent quitters (i.e. had given up in the past year). In the 2014-15 survey 8.5% of adults had ever used e-cigarettes and 2.4% were currently using them. Men were more likely to use e-cigarettes than women, and younger people more likely than older people. Only 2% of those who had never smoked had used e-cigarettes while 38.2% of current smokers and 49.3% of recent quitters had used them.

Quit rates were compared between the five surveys studied. Using the 2001-02 survey as a baseline both the 2010-11 and 2014-15 surveys showed significantly higher quit attempt rates (P < 0.05 and P < 0.001), with a large jump in quit attempt rates in 2014-15.

The annual cessation rate figures followed a similar pattern of increase, although the increase was only statistically significant comparing the rate for 2014-15 with that for 2010-11: 5.6% vs 4.5%.

Taking data from the 2014-15 survey, e-cigarette users had a higher cessation rate than those who had not used e-cigarettes in the preceding year; 8.2% vs 4.8%, respectively, P < 0.001.

This study has demonstrated two important findings. First, in 2014-15 e-cigarette users in the United States attempted and succeeded in quitting at higher rates than non-users. Second, the overall population smoking cessation rates had increased in 2014-15 compared with 2010-11, the same period that saw e-cigarettes come into popular usage.

The study authors, from the University of California, conclude: ‘This study based on the largest representative sample of e-cigarette users to date, provides a strong case that e-cigarette use was associated with an increase in smoking cessation at the population level.’

Dr Jez Thompson