Patterns of Electronic Cigarette Use Among Adults in the United States.

INTRODUCTION Amid increasing rates of electronic cigarette (e-cigarette) use in the United States, there is an urgent need to monitor patterns of use at the population level in order to inform practice, policy and regulation. This article examines how patterns of e-cigarette use among adults differ between users and nonusers of cigarettes using the most current national data. METHODS We analyzed data from the 2014 National Health Interview Survey. We estimated prevalence of ever, current, and daily e-cigarette use and examined how use patterns differed by demographic subgroups and measures of cigarette smoking status that accounted for the recent availability of e-cigarettes in the US marketplace. RESULTS Current e-cigarette use is extremely low among never cigarette smokers (0.4%) and former smokers who quit cigarettes 4 or more years ago (0.8%). Although e-cigarette experimentation is most common among current cigarette smokers and young adults, daily use is highest among former smokers who quit in the past year (13.0%) and older adults. Compared to daily cigarette smokers, recently quit smokers were more than four times as likely to be daily users of e-cigarettes (AOR: 4.33 [95% CI: 3.08-6.09]). CONCLUSIONS Extremely low e-cigarette use among never-smokers and longer term former smokers suggest that e-cigarettes neither promote widespread initiation nor relapse among adults. Recognition of the heterogeneity of smokers, including the time since quitting, is critical to draw accurate conclusions about patterns of e-cigarette use at the population level and its potential for public health benefit or harm. IMPLICATIONS Data from 2014 National Health Interview Survey indicate that e-cigarettes have not been attracting adult non-smokers or promoting relapse in longer term former smokers. Moreover, the data are suggestive that some recent quitters may have done so with the assistance of e-cigarettes. Creating measures of smoking status that treat former smokers as a homogenous group is insufficient to assess the epidemiology of e-cigarette use and the potential impact on public health.