Trends in Awareness, Use of, and Beliefs About Electronic Cigarette and Snus Among a Longitudinal Cohort of US Midwest Young Adults.

Introduction: Few longitudinal studies have examined how awareness, use of, and beliefs about electronic cigarettes (e-cigarettes) and snus change over time. We assessed these trends in a cohort of young adults from the US Midwest. Methods: Data were from the Minnesota Adolescent Community Cohort (MACC) Study, collected annually during 2010-2013 when participants were 21-29 years old (n = 2622). Participants were asked if they had heard of and ever used e-cigarettes and snus, and the number of days they used these products in the past 30 days. Beliefs about whether these products are less harmful than cigarettes, less addictive than cigarettes, and could help people quit smoking were assessed. Repeated measures multiple linear and logistic regression models, adjusting for demographics, peer smoking and smoking status, were used to assess trends. Results: Compared to 2010-2011, participants in 2012-2013 were five times more likely to be aware of e-cigarettes, report ever used them, and report using them in the past 30-days. Increases in e-cigarette use were observed in all smoking status. Participants were also increasingly likely to believe that e-cigarettes are less harmful than combustible cigarettes and could help people quit smoking. There was only a modest increase in awareness of and ever using snus, as well as believing snus is less harmful than combustible cigarettes. These trends did not differ by smoking status. Conclusions: The increasingly favorable beliefs about e-cigarettes may explain the increasing prevalence of their use particularly among young adults, both among smokers and nonsmokers. Implications: Awareness and use of e-cigarettes have increased substantially over the past few years, and positive beliefs of e-cigarettes have also become more prevalent among young adults. Meanwhile, little changes in awareness, use of, and beliefs about snus among young adults. Given the potential of these products to have both positive and negative impact on public health depending on who use them and how they are used, strategically communicating the risks associated with e-cigarettes and snus use may help minimize the burden of tobacco use at the population level.