Please cite this article in press as: Farsalinos, K. E., et al. Factors associated with dual use of tobacco and electronic cigarettes: A case control study. International Journal of Drug Policy (2015), http://dx.doi.org/10.1016/j.drugpo.2015.01.006 ARTICLE IN PRESS G Model DRUPOL-1513; No. of Pages 6 International Journal of Drug Policy xxx (2015) xxx–xxx Contents lists available at ScienceDirect International Journal of Drug Policy j ourna l h om epage: www.elsevier.com/locate/drugpo Research paper Factors associated with dual use of tobacco and electronic cigarettes: A case control study Konstantinos E. Farsalinos a,b,∗ , Giorgio Romagna c , Vassilis Voudris a a Onassis Cardiac Surgery Center, Greece b University of Patras, Greece c ABICH S.r.l, Biological and Chemical Toxicology Research Laboratory, Italy a r t i c l e i n f o Article history: Received 21 November 2014 Received in revised form 5 January 2015 Accepted 7 January 2015 Keywords: Electronic cigarette Smoking Tobacco Nicotine Harm reduction Public health Dual use a b s t r a c t Background: Many electronic cigarette (EC) users reduce cigarette consumption without completely quit- ting. It is important to assess the characteristics and experiences of these users, commonly called “dual users”, in comparison with EC users who have completely substituted smoking (non-smoking vapers). Methods: A questionnaire was uploaded in an online survey tool. EC users were invited to participate irrespective of their current smoking status. Dual users were matched for age and gender with non- smoking vapers. Results: From 19,441 participants, 3682 were dual users. After random 1:1 matching with non-smoking vapers (all of whom were former smokers), 3530 participants in each group were compared. Dual users had longer smoking history, lower daily cigarette consumption and similar cigarette dependence com- pared to non-smoking vapers. Their daily consumption was reduced after initiation of EC use from 20 to 4 cigarettes per day. Most of them were using ECs daily, however, more were occasional EC users compared to non-smoking vapers. Use of advanced (third generation) devices and daily liquid consumption was lower in dual users compared to non-smoking vapers. The most important reason for initiating EC use was to reduce smoking and exposure of family members to smoke for both groups, but higher scores were given to “avoid smoking ban in public places” by dual users compared to non-smoking vapers. The strongest predictors of being dual user from multivariate analysis were: higher risk perception for ECs (OR = 2.27, 95% CI = 1.40–3.68), use of first-generation EC devices (OR = 1.98, 95% CI = 1.47–2.66), use of prefilled cartomizers (OR = 1.94, 95% CI = 1.23–3.06) and occasional use of ECs (OR = 1.62, 95% CI = 1.21–2.17). Conclusions: The results of this case-control study indicate that higher risk perceptions about, and less frequent use of, ECs was associated with dual use of ECs and tobacco cigarettes. Since this is a cross- sectional survey, which explores association but not causation, longitudinal studies are warranted to further explore the reasons for dual use. © 2015 Elsevier B.V. All rights reserved. Introduction Electronic cigarettes (ECs) have been marketed in recent years as alternatives to smoking. They are electrically-driven devices, used to vaporise a liquid that may or may not contain nicotine. They consist of a battery part (usually lithium battery), and an atomizer where liquid is stored and is aerosolized by heating a resistance encircling a wick. The main ingredients of liquids are ∗ Corresponding author at: Onassis Cardiac Surgery Center, Department of Cardi- ology, Sygrou 356, Kallithea 17674, Greece. Tel.: +30 6977454837; fax: +30 2109493373. E-mail address: kfarsalinos@gmail.com (K.E. Farsalinos). propylene glycol, glycerol and a variety of flavourings. A huge variety of devices and different liquids are available, with the main purpose to satisfy users’ need and preference. The powerful addictive properties of nicotine and of the ritu- alistic behaviour of smoking make smoking cessation a difficult task. Currently-approved products for smoking cessation have low long-term quit rates, with nicotine replacement therapy having less than 7% sustained abstinence rate (Moore et al., 2009), while oral medications have less than 20% quit rate at one year (Rigotti et al., 2010). Therefore, tobacco harm reduction strategies and products have been developed, with the goal to reduce smoking- related morbidity and mortality burden by providing nicotine in a less harmful form (Rodu & Godshall, 2006). ECs are tobacco harm reduction products that may deal with both chemical (through http://dx.doi.org/10.1016/j.drugpo.2015.01.006 0955-3959/© 2015 Elsevier B.V. All rights reserved.