Nicotine-Dependence-Varying Effects of Electronic Cigarette Use on the Regularity of Conventional Cigarette Smoking

Introduction: The concurrent use of multiple tobacco products is an emerging trend among young smokers. Electronic cigarettes (“e-cigs”) are of particular interest, considering the drastic increase in their use in recent years. E-cigs are controversial, with some arguing that they may be beneficial from a harm-reduction perspective, while others raise concerns that e-cigs may attract new smokers of conventional cigarettes. Few studies have accounted for the role of nicotine dependence (ND), a primary driver of tobacco use. The current study examines the relationship between e-cig use and conventional cigarette use among young adult smokers, and how this relationship varies across the spectrum of ND severity.

Methods: Data were drawn from the Social and Emotional Contexts of Adolescent Smoking Patterns (SECASP) Study, a longitudinal study oversampling light and novice adolescent smokers. Variants of time-varying effect models (TVEM) were used in order to examine the relationship between recent e-cig use and recent smoking regularity, and the possible moderation of this relationship across the continuous spectrum of ND.

Results: At very low levels of ND, e-cig usage was negatively associated with regular use of conventional cigarettes. However, at moderate to high levels of ND, e-cig use was associated with more frequent smoking of conventional cigarettes. This finding held true even among those who entered the study as non-smokers.

Conclusions: These findings show that e-cig users with low ND tend to smoke conventional cigarettes less regularly, but those with moderate and high ND tend to more frequently smoke conventional cigarettes. ND may motivate the use of multiple tobacco products, though it remains unclear whether 1) e-cig users transition to conventional cigarettes after developing ND, or 2) conventional smokers transition to e-cigs as a harm reduction strategy after developing ND. Future research is needed to examine the temporal ordering of different tobacco product use, and their relation to ND.