Type of E-Cigarette Device Used Among Adolescents and Young Adults: Findings From a Pooled Analysis of Eight Studies of 2166 Vapers

Abstract

Background

A recent study of adult smokers who vape found that disposable/cigalike electronic (e-) cigarette devices were more commonly used than later generation devices. However, whether these trends reflect patterns among adolescents and young adults, many of whom have limited or no history of combustible cigarette use, has not been studied.

Methods

Participants were drawn from eight locally, regionally, and US nationally representative studies. Surveys took place between Fall 2014 and Spring 2016; participants were residents of California (3 studies), Texas (2 studies), Connecticut (1 study), or randomly selected from the US population (2 studies). Data were collected from middle and high school students (4 studies), young adults under 30 (3 studies), or a mixture (1 study) to assess type of e-cigarette device used among past-30 day e-cigarette users: disposable/cigalike, or later generation e-cigarette device.

Results

Fewer than 15% of participants in each study reported primarily using a disposable/cigalike device in the past month (across all studies: 7.5%; 95%CI: 4.9%, 10.5%). The proportion using later generation devices ranged from 58% to 86% across studies; overall, 77.0% (95%CI: 70.5%, 82.9%) reported primary use of a later generation device. Combined, 13.2% (95%CI: 5.9%, 22.8%) reported “don’t know” or were missing data.

Conclusions

Among adolescent and young adult e-cigarette users, primary use of disposable/cigalike devices was rare. Future research should continue to evaluate the type of device used by adolescents and young adults, as these data may be relevant to regulatory oversight of e-cigarettes recently acquired by the Food and Drug Administration Center for Tobacco Products.

Implications

In this pooled analysis of adolescent and young adult vapers, primary use of later generation e-cigarette devices was substantially more common than use of disposable/cigalike devices. The type of device predominantly used by adolescents and young adults has regulatory implications for policy to reduce adolescent use of e-cigarettes.

Introduction

E-cigarettes have risen in popularity, especially among adolescents and young adults.^1–4 There is considerable variability in the different types of commercially available e-cigarettes, and in terminology used to describe e-cigarettes, which makes assessment of e-cigarette use difficult and poses challenges for translating e-cigarette research into evidence-based regulatory policy.^5,6 In a recent study of US adult smokers who vape, 51% used only disposable e-cigarettes (or “cigalikes”), 41% used only later generation models (eg, rechargeable, pen-like devices, devices that use tanks or cartridges, or mods/mech-mods), and 8% did not have a preferred device.⁷ No data have been published on the device type used in the adolescent and young adult population of vapers, many of whom do not smoke combustible cigarettes.^8–10

Different devices produce aerosols that may differ in the levels of toxins^11,12 and nicotine delivery and absorption into the bloodstream,¹³ and may result in disparate use patterns.^7,14 Therefore, the type of device predominantly used by adolescents and young adults has important methodological implications for experimental and observational research on the toxicity, abuse liability, health hazards (eg, respiratory or cardiovascular effects), possibilities for smoking-cessation, and other public health impact of e-cigarette use. Here, we report the prevalence of using different device types among a combined 2166 adolescent and young adult e-cigarette users across eight different studies.

Methods

Participants

Participants were past 30-day e-cigarette users from eight locally, regionally, and US nationally representative studies (Supplementary Table 1).^9,10,15–20 Surveys took place between Fall 2014 and Spring 2016 and participants were residents of California (3 studies), Texas (2 studies), Connecticut (1 study), or randomly selected from the US population (2 studies). Data were collected from middle and high school students (4 studies), young adults under 30 years old (3 studies), or both (1 study). Surveys were administered in school (2 studies), online (5 studies), or by phone (1 study).

Measures

In addition to demographics and past 30-day e-cigarette use, each study included questions asking respondents to select all e-cigarette device types they had used, or the device type that they had used most often (see Supplementary Table 2). Five studies also included a photo of different device types corresponding with the text descriptions of each type. All studies asked participants whether their device was either disposable or a “cigalike”; later generation devices were assessed using terminology such as “containing tanks or cartridges,” “vape pen or pen-like device,” “mod or mech-mod/rebuildable” and/or another term (see Table 1 note for details). For this report, we grouped all non-cigalike models into a combined Later Generation Device category to be compared with cigalike models in the combined Disposable/Cigalike category.

Analysis

For individual studies, proportions and 95% confidence intervals [CI] were computed, using either a Wald-type interval on the log-odds scale obtained from a weighted logistic regression model transformed to the probability scale (weighted samples; studies 1–2) or using the Wilson method (unweighted samples; studies 3–8).

For studies that used a “choose-all-that-apply” question format for type of device (eg, allowing multiple responses; studies 5–7), categories were constructed based on whether participants selected only a disposable/cigalike device or only a later generation device; participants who selected both types of devices or reported “don’t know” are included in the “other” category (Table 1). Summary estimates were calculated by type of study (choose-all-that-apply vs. forced-choice) using a pooling procedure for analysis of multiple studies using a random effects model with the estimate of heterogeneity from the inverse-variance fixed-effect model, and inclusion of the Freeman–Tukey Double Arcsine Transformation to stabilize variances; 95%CI were computed using the Wilson method, with a test for heterogeneity between subgroups. A ratio of later generation device use to disposable/cigalike use was computed by dividing prevalence estimates, respectively. Pooled analyses were completed using Stata v.13.1.

Results

Past 30-day e-cigarette use ranged from 3.5% (95%CI: 2.8%, 4.3%; study 6) to 13.2% (95%CI: 11.6%, 15.1%; study 4; Supplementary Table 1). Across the eight studies, 8.0% (95%CI: 5.1%, 11.5%) reported primary use of a disposable/cigalike device and 77.0% (95%CI: 70.6%, 82.9%) reported primary use of a later generation device (Table 1). The proportion using later generation devices ranged from 58% to 86% across studies, with most studies reporting around 80% use. In all studies, the prevalence of using later generation devices was substantially higher than disposable/cigalike use. The heterogeneity in prevalence across studies overall for later generation (I² = 89.1%; p < .05) or cigalike/disposable (I² = 82.2%; p < .05) devices was high; however, later generation devices were preferred regardless of age, geographic location, date of data collection, method of data collection, or the specific questionnaire item used in each study.

Discussion

As the first report of the prevalence of e-cigarette device types used among adolescents and young adults, this study provides new evidence that the majority of young vapers use later generation devices. Although there was variation in terminology²¹ to identify the products on surveys, use of later generation devices was more common in all studies. Predominant use of disposable/cigalike devices was relatively rare among the adolescents and young adults surveyed in the eight studies included in this report. In contrast, an earlier study of adult smokers (with 96% of the sample aged 25 or older) found that the prevalence of disposable/cigalike use was slightly higher than later generation device use overall, and substantially higher among adults 65 or older (27.4% later generation use only vs. 66.6% disposable/cigalike use), and among adults aged 45–64 (31.4% vs. 59.8%).⁷

Differences between later generation and disposable/cigalike devices may be responsible for different physiological (eg, health effects) or behavioral consequences (eg, abuse liability, utility as a cessation aid) of e-cigarette use. Later generation devices allow the user to customize their product (e.g., temperature and power settings for vaporization can often be adjusted), and e-cigarette solutions in a wide variety of flavors and nicotine levels can be purchased independently of the device. Later generation devices also typically deliver aerosols to the lungs more efficiently,¹³ with greater variability in delivery depending on voltage and temperature settings.^11,13 The type of device used can thus affect the level of toxins^11,12 and concentration of nicotine¹³ in the aerosol; in combination with e-liquid solutions, the type of device may also impact the overall sensory experience, appeal, and abuse liability of e-cigarette use. Thus, characteristics of the device (eg, voltage, temperature) and e-cigarette solution (eg, flavorings, nicotine level) in concert with overall device type (disposable vs. later generation) are relevant to research and to the development of policy. Future research is warranted to evaluate factors that may explain the observed preference for later generation devices among adolescents and young adults.

In light of e-cigarettes recently being deemed a “tobacco product” under the regulatory authority of the Food and Drug Administration,²² understanding the prevalence as well as the adverse and beneficial effects of using different e-cigarette device types is needed. The new regulations will require a premarket review and approval by August 2018 for most e-cigarette devices and e-liquids²² which may present a greater burden on manufacturers and retailers of later generation devices that are owned primarily by smaller companies,²³ possibly resulting in decreased availability of such products. Consequently, disposable/cigalike products, which are largely owned by large tobacco companies,²³ may become the dominant device type available on the market. Based on the current results, such a change in the regulatory environment could potentially reduce initiation of e-cigarette use among adolescents and young adults, although it is unclear whether current e-cigarette users would discontinue use of e-cigarettes or would transition to disposable/cigalike devices or other nicotine products.

Supplementary Material

Supplementary data are available at Nicotine & Tobacco Research online.

Funding

Research reported in this publication was supported by grant number P50CA180905 (JLBT, AML, RM), P50CA179546 (LAG), P50CA180890 (BHF), and P50CA180906 (MBH and AL) from the National Cancer Institute at the National Institutes of Health (NIH) and the Food and Drug Administration (FDA) Center for Tobacco Products (CTP); grant number P50DA036128 (SRW) and P50DA036151 (GK and SKS) from the National Institute on Drug Abuse (NIDA) at the NIH and FDA CTP; grant number R01-DA033296 (AML) from NIDA at the NIH. No funders had any role in the design and conduct of the study; collection, management, analysis, or interpretation of the data; or preparation, review, or approval of the manuscript. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH or the Food and Drug Administration.

Declaration of Interests

None declared.

Acknowledgments

We would like to thank the following individuals for their contribution to this manuscript: David Cash (Stanford University), Kevin Delucchi (University of California San Francisco), John Wesley Heath (Georgia State University), Xiaoyin Li and Josephine T. Hinds (University of Texas at Austin), Christian Jackson and Joanne Delk (UT Health, School of Public Health), Ran Wu (Yale School of Medicine), Matt Stone and Feifei Liu (University of Southern California). We would also like to thank all the adolescents, young adults, teachers, and students who participated in or helped facilitate data collection for these studies.

References