Readiness to stop smoking and subsequent switching away to electronic nicotine delivery systems among adults who smoke cigarettes

<i>Background:</i> Adults who smoke cigarettes (AWS) who switch to electronic nicotine delivery systems (ENDS) are likely to reduce their health risks. <i>Objectives:</i> To explore ENDS-users’ readiness to stop smoking (RTSS) when adopting ENDS, the prospective association of RTSS and switching away from smoking (past-30-day abstinence), and the role of frequency of JUUL use in switching. <i>Methods:</i> Analyses used data from a naturalistic 2-year longitudinal study of 17,393 AWS (55.4% male) who had purchased a JUUL Starter Kit. <i>Results:</i> Only 20% were planning to stop smoking within 7 days at baseline but had the highest likelihood of switching, 70% at Month-24 (vs. in a year or more: OR = 2.33; 95%CI = 2.13–2.55). Those planning to stop smoking within 30 days (24%), 6 months (24%) or a year or more (27%) had switch rates of 53 ~ 59% at Month-24; those who planned never to quit (6%) had 51% switch rates. Daily ENDS use was prospectively associated with the highest likelihood of subsequent switching (vs. infrequent: OR = 1.68; 95%CI = 1.60–1.77); frequent users (≥20 days/month) also had higher switch rates (OR = 1.22; 95%CI = 1.15–1.28). Descriptively, participants higher on RTSS were more likely to be daily or frequent users, but frequency of use neither interacted with RTSS, nor mediated its association with switching. <i>Conclusions:</i> Most ENDS adopters were not ready to stop smoking, and would not be candidates for cessation treatment. However, a majority – even of those never planning to quit – were abstinent from cigarettes two years later. ENDS may facilitate smoking abstinence in populations not reached by traditional cessation interventions.