Patterns and Frequency of Current e-Cigarette Use in United States Adults.

Background: In the United States (US), electronic cigarette (e-cigarette) use prevalence has increased since 2010. Few studies, however, have addressed frequency of use at the population-level. This study examines patterns and correlates of e-cigarette use frequency in a novel national sample.
Methods: Data were from 36,277 US adults interviewed between 2012 and 2013 for the National Epidemiologic Survey on Alcohol and Related Conditions-III (NESARC-III). Sociodemographic characteristics, other tobacco/drug use, and psychiatric disorders were compared by e-cigarette use status (i.e. current [past-month], past, never) and e-cigarette use frequency (i.e. infrequent [≤3 days/month], moderate [1-6 days/week], daily). Multinomial logistic regression models compared correlates of e-cigarette use status and e-cigarette use frequency.
Results: Current e-cigarette use was low in adults (1.4%) and past e-cigarette use was 3.9%. Among current e-cigarette users, 38.1% were infrequent users, 32.9% were moderate users, and 29.0% were daily users. Compared to infrequent e-cigarette users, daily users were more likely to be male and older, but less likely to be current cigarette smokers and alcohol drinkers (p's < .05). Compared to daily e-cigarette users, moderate users were more likely be female, current cigarette smokers, and fall into the 25-34 age group (p's < .05). Moderate and daily e-cigarette users had higher prevalence of current extra-medical opioid use than infrequent users (p's < .05). Conclusions/Importance: E-cigarette users were most often infrequent users versus moderate or daily users. Compared to infrequent and moderate users, daily e-cigarette users were less likely to be current alcohol drinkers or cigarette smokers. Novel findings highlight a correlation between more frequent e-cigarette and opioid use.