Electronic nicotine delivery systems (ENDS; also known as e-cigarettes) have been identified as a potential tool to help people quit smoking cigarettes. A recent population-based, prospective cohort study examined the association between quitting smoking and ENDS use among a random probability sample of U.S. adult smokers. Participants (N = 1,284) were recruited from respondents who identified as smokers on a 2015 survey. This survey served as the baseline for the current study. A subset of participants (N = 1,018) was also asked to complete a follow-up survey one year later, which yielded a final sample size of 858 respondents (66.8% of baseline smokers and 84% of those invited to take the follow-up survey). The primary outcome variable was smoking abstinence for at least one month prior to follow-up. Secondary outcome variables included making a quit attempt between baseline and follow-up, number of successful quit attempts, and average number of cigarettes smoked per day. Primary ENDS exposure variables included frequency of use of non-marijuana ENDS products at baseline, between baseline and follow-up, and one month prior to follow-up. Three hundred forty-seven participants were classified as ENDS users, of whom 129 reported use at baseline and follow-up, 53 reported use during the study period but not at baseline, and 165 reported use at or after baseline, but not at follow-up. The authors also collected data on frequency of ENDS use, importance of quitting smoking as a reason for using ENDS, and ENDS product characteristics, as these factors were considered potential effect modifiers of ENDS use. Results indicated 27.1% (95% confidence interval [CI]: 22.6%, 32.0%) of smokers reported using ENDS at baseline; at follow-up, 90% of this group continued to use ENDS. Data were analyzed using weighted logistic regression or weighted general linear models to assess whether ENDS users were more likely to smoke daily at baseline and whether they differed across covariates. Among smokers who reported a quit attempt, the authors used estimated weighted proportions for each method. The proportion of ENDS non-users at baseline who smoked daily did not significantly differ from the proportion of ENDS users at baseline (p = 0.56). Compared to smokers who did not use ENDS, ENDS users during the study period were younger and more likely to report being addicted to cigarettes. No significant differences were observed between ENDS users and non-users for baseline quit intentions, number of quit attempts, or number of years smoking. Smokers who used ENDS during the study period had nearly double the adjusted odds of making a quit attempt compared to those who did not use ENDS during this period (adjusted odds ratio [AOR] = 1.92, CI: 1.15 – 3.19); however, this association became non-significant when multiple imputation was used to handle missing data. Overall, smokers who used ENDS were more likely to attempt to quit smoking than non-users; however, the authors found no evidence that ENDS helped smokers quit a higher rate than smokers who did not use ENDS products. One limitations of this study was its observational design, which precluded researchers from drawing conclusions about causality.
Take away: In this study, which sought to investigate electronic nicotine delivery systems (ENDS) use and cigarette smoking under ‘real world’ conditions, the authors found no evidence that ENDS use helped adult smokers quit at higher rates than smokers who did not use ENDS. Ninety percent of ENDS users at baseline reported continuing to use ENDS products one year later.
Weaver, S.R., Huang, J., Pechacek, T.F., Heath, J.W., Ashley, D.L. & Eriksen, M.P. (2018). Are electronic nicotine delivery systems helping cigarette smokers quit? Evidence from a prospective cohort study of U.S. adult smokers. PLoS One [published online ahead of print July 9, 2018] doi: 10.1371/journal.pone.0198047