Factors associated with dual use of tobacco and electronic cigarettes: A case control study

Highlights

• A case control study of 7060 electronic cigarette users was performed.

• Factors associated with dual use of electronic and tobacco cigarettes were assessed.

• Risk perception was the strongest independent predictor of dual use.

• Occasional use and use of old-generation devices were also associated with dual use.

• Proper information about electronic cigarette risks is important to avoid dual use.

Abstract

Background

Many electronic cigarette (EC) users reduce cigarette consumption without completely quitting. 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 compared 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.

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 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 ritualistic 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 nicotine delivery) and behavioural (through motor simulation and sensory stimulation) addiction to smoking (Farsalinos, Romagna, Tsiapras, Kyrzopoulos, & Voudris, 2013). Awareness and use of ECs are growing exponentially, but there is controversy over their potential as smoking substitutes. Surveys have shown that they may be effective in promoting reduction of cigarette consumption or even complete abstinence (Dawkins et al., 2013, Etter and Bullen, 2011). Cross-sectional studies have raised doubts whether ECs promote smoking cessation (Popova and Ling, 2013, Vickerman et al., 2013) but recently-published randomized studies showed a significant potential of ECs to promote smoking reduction and cessation, even in smokers with no intention to quit (Adriaens et al., 2014, Bullen et al., 2013, Caponnetto et al., 2013). Still, many EC users fail to completely substitute smoking, and thus become “dual users”. It is important to understand the characteristics, patterns of use and perceived experience of dual users compared to EC users who have completely substituted smoking with EC use (non-smoking vapers). The purpose of this case-control study was to identify the different characteristics of these two groups in a worldwide sample of EC users, by providing a questionnaire in several languages and by promoting the study through the Internet.