Skip to main content
NIHPA Author Manuscripts logoLink to NIHPA Author Manuscripts
. Author manuscript; available in PMC: 2021 Jul 1.
Published in final edited form as: J Adolesc Health. 2020 Mar 16;67(1):46–52. doi: 10.1016/j.jadohealth.2020.01.017

How and why California young adults are using different brands of pod-type e-cigarettes in 2019: Implications for researchers and regulators

Karma McKelvey 1, Bonnie Halpern-Felsher 1,*
PMCID: PMC7311231  NIHMSID: NIHMS1569034  PMID: 32192827

Abstract

Objectives

To describe young adult use and perceptions across different brands of pod-based e-cigarettes and compare with earlier types of non-pod-based-e-cigarettes (e.g., mods, tanks).

Methods

Data were collected January-March 2019 and derive from the final wave of a cohort study recruited in 2013–14 using a convenience sample from ten large California high schools with racially/ethnically and socioeconomically diverse populations. Participants (N=445) completed an online survey and were mean age=20.1 (SD=1.66); 64.8% female (n=278); 38.8% (n=161) white; 23.9% (n=99) each “more than one race” and Asian; 13.5% (N=56) other; and 36.9% (n=160) Hispanic. Main outcomes were description of and reasons to use pods, perceived nicotine content, and use patterns.

Results

While <25% reported smoking cigarettes and using non-pod-based-e-cigarettes, >25% reported ever-use of Juul. Similarly, <33% of cigarette smokers and non-pod-based-e-cigarette users reported use in past 30-days, >50% of Juul ever-users did. The most agreed-upon reason (58%) for using pods was because they are “easy to hide.” About half of pod users “don’t know” if they mix brands of e-juice and pods, the nicotine concentration in their e-juice cartridges, nor time to finish a cartridge; of the 50% who shared their pod n=23 (15%) did “sometimes;” n=20 (13%) “always;” and n=16 (11% each) “about half the time” or “often.” There was no consensus about how different brands of pods were referred to.

Conclusions

Our findings indicate young adults harbor confusion about pod-based e-cigarettes, including nicotine content, usage patterns, and labeling, and that pods use is largely due to the ease with which they can “stealth” vape. The findings suggest needed regulation and education about these products.

INTRODUCTION

Among U.S. 18–24 year-olds, the prevalence of electronic cigarette (e-cigarette) use is 7.6%, nearly twice the prevalence among adults age 26–44 (4.3%).1 E-cigarette use is dangerous for young adults, especially among those who initiate nicotine with e-cigarettes, as research shows e-cigarettes result in nicotine dependence, use can increase likelihood of cigarette smoking;25 further, e-cigarette use itself is associated with cardiovascular disease6 and lung injury,7 among other health conditions. These statistics have prompted both the former commissioner of the U.S. Food and Drug Administration and the US surgeon general to refer to vaping as an epidemic among teenagers and youth, respectively.8,9 This dramatic, rapid increase in e-cigarette use has been attributed to use of pod-based e-cigarettes (hereinafter “pods”), made popular by the brand Juul,10 although other pods using similar technology and nicotine salt-based nicotine, like Juul, are also being used. A study using a probability-based U.S. sample showed 20.7% of adolescents and young adults aged 15–21 years ever used a Juul, and 13.8% were current users.11

While studies among adolescents and young adults have shown that the most popular brands of pods are Juul, Bo, Phix, and Sourin,12 most studies examining use and related knowledge, attitudes, and perceptions of these newer e-cigarette products (“pods”) have focused on the Juul brand and its strong online and social-media advertising presence.4,7,8 Explanations for the widespread adoption of Juul by adolescents and young adults include availability of youth-friendly flavors (young adults prefer menthol, mint, fruit, and “sweets” flavors);15,16 ability to use where it is not allowed and in stealthier, more concealed ways;12,1719 and incorrect beliefs about e-juice contents, including nicotine levels.20 Adolescents and young adults who exclusively use pods have been found to inhale, in 10 puffs, from 0.77 to 0.85 mg of nicotine, which is considerably higher than older generations of non-pod-based-e-cigarettes (0.02–0.51 mg/10 puffs)12 and 13.7% of college students who use Juul use them daily.20 The sleek, small, and “hightech” look of pod-based e-cigarettes also make them easy to hide and may not appear to even be an e-cigarette.19 Finally, 30.1% believe the e-juice cartridges (“cartridges”) contain only nicotine and flavoring,20 and young adults do not know that all Juul cartridges contain nicotine.15,16,21 Both the style and the efficient delivery of high-levels of nicotine are hypothesized contributors to continued use and addiction among adolescents and young adults.15,18,2224

No studies have focused on understanding young adult use and perceptions across different brands of pods, including “closed” systems like Juul, Phix, and Myblu, where the cartridges are not made to be refilled, as well as Suorin Drop (a refillable or “open” pod system). To address existing scientific gaps and contribute to the evidence base needed to develop prevention and cessation programs targeting young adults, we collected detailed data on how and the frequency at which California young adults use different brands of pods. Questions were designed to illuminate how much they know about the pods they are using, including why they use particular pods, if they share their pods, cartridge nicotine concentrations and perceptions of product nicotine levels, whether they mix brands of devices with different brands of e-juices, and their reasons for using. Data of this nature are necessary to ensure research on pods captures true prevalence and use patterns and can be used to inform product regulation and develop public health and tobacco control messaging.

METHODS

Participants and Procedure

Data used for this cross-sectional study constitute completers (N=445) of the 8th and final wave of data collection for this prospective cohort study and were collected January 22 to March 19, 2019, about 2.5 years after the legal age to purchase tobacco rose to age 21. Wave 8 was the only wave that asked detailed questions about different pod-based e-cigarettes. The study originated in 2013–14, with the recruitment of a convenience sample from 10 high schools in California with racially, ethnically, and socioeconomically diverse populations. Each of the 9th and 12th grade classes in the schools were visited by study personnel, and all students in those classes were invited to participate. Students interested in participating signed and returned assent and parental consent forms. Several days later, study personnel returned to the schools, collected forms, and answered any questions. A total of N=722 (56%) of N=1,299 consented students completed the baseline survey. More details of the study design and methods are published elsewhere.16,25

The Wave 8 sample [mean age 20.1 (SD=1.66, range 17–24); 64.8% (n=278) female; 36.9% (n=160) Hispanic ethnicity; 38.8% (n=161) white, 23.9% (n=99) Asian, 23.9% (n=99) more than one race, and 13.5% (n=56) “other”] had fewer males than the schools from which they were recruited; nonetheless, participant demographics reflected the demographic make-up of the schools they attended. The sample in this study was more diverse with respect to race and ethnicity compared to the population of young adults in California or the US. Participants answered an online survey administered by Qualtrics (Provo, UT) and received $45 upon completion. Stanford University’s institutional review board approved all procedures.

Measures

All questions in this study were either based on or identical to those used in our prior research16,26,27 and were pilot-tested prior to inclusion. To help ensure participants use the same definitions for the included products,28 participants viewed pictures and descriptions of the different types of e-cigarettes before answering detailed questions. To help ensure participants understood the categories “non-pod-based-e-cigarettes” and “pods” are mutually exclusive and discrete, non-pod-based-e-cigarettes were defined as “…types of electronic cigarettes, often called e-cigarettes, e-cigs, vapes, vape pens, or e-hookahs, that DO NOT include pod-type vapes such as JUULs, Suorin Drop, Phix or Myblu”) and pods as “… JUULs and other pod-type vape products such as Suorin Drop, Phix or Myblu”).

Prior to seeing the above-referenced pictures and descriptions of non-pod-based-e-cigarettes and pods, participants were asked: “Before today, other than in these surveys, which of the following products have you ever heard of (please check all that apply)?” Response choices included: Juul, Suorin Drop, Phix or Myblu. Participants who indicated they had heard of one or more of the pods were then asked, separately for each brand they recognized (i.e., Juul, Suorin Drop, Phix, and Myblu), the following:

Pod Descriptions

Participants were asked which best describes each (pod brand)? Response choices included: type of e-cigarette, type of vape, type of pod, type of nicotine-delivery device, other. Participants chose as many responses as they felt applied.

Nicotine Content

Separately for non-pod-based-e-cigarettes, and each of the four pod brands assessed in this study, participants were asked three sets of questions concerning nicotine: (1) How much nicotine do you think pods contain in general? (2) How much nicotine do you think (pod brand) contains? Response choices for these two questions were pilot tested and included the correct nicotine concentration and random plausible other concentrations, which for both questions were 0 mg/ml, 3 mg/ml, 5 mg/ml, 12 mg/ml, 36 mg/ml, 59 mg/ml, 72 mg/ml, don’t know. (3) Complete the statement: Do (pod brand) have (MORE nicotine than a pack of cigarettes? LESS nicotine than a pack of cigarettes? The SAME amount of nicotine as a pack of cigarettes? Don’t know).

First Tobacco Product Used

Separately for non-pod-based-e-cigarettes, and each of the four pod brands assessed in this study, those reporting any tobacco use were asked about the first tobacco product they had ever used. [Response choices included: cigarettes, non-pod-based-e-cigarettes, hookah, and Juul].

Cigarette, Non-pod-based-e-cigarette, and Pod Use

Separately for cigarettes, non-pod-based-e-cigarettes, and each of the four pod brands assessed in this study, all participants were asked about ever-use; ever-users were then asked number of days used in the past 30 and first tobacco product used. Ever-users only of pods were asked, separately for each brand used: (1) whether they first used pods or non-pod-based-e-cigarettes; (2) reasons for use [participants were asked if they agreed or disagreed with the following statements about pods: They… (a) are easy to hide, (b) are healthier than other types of vapes, (c) are easier to buy than other types of vapes, (d) are more stylish to use than other types of vapes, (e) have more nicotine than other tobacco products, (f) have less nicotine than other tobacco products, (g) taste better than other types of vapes, (h) have more/better flavors than other types of vapes, (i) the aerosol/vapor is less obvious than other types of vapes, and (j) the smell they produce is less obvious than other types of vapes]; (3) brand(s) of e-juice and/or cartridge(s) (“e-juice/cartridge”) used; and (4) whether and as follow-up (5) how often they share their pod-type vape [(a) never, (b) sometimes, (c) about half the time, (d) often, and (e) always]. Rate of e-juice/cartridge use was assessed using the following three questions: (1) About how many [brand] cartridges do you finish in a day? (2) About how many [brand] cartridges do you usually finish in a week? and (3) How long does it usually take you to finish 1 pod or cartridge?

Sample Size and Potential Bias

The original sampling frame was all students in the 9th and 12th grades from the 10 participating high schools. The overarching goal of this cohort study was to look at changes in use and perceptions of tobacco products over time, not to make population level estimates. Analysis for this study was constrained to the latest wave, which focused on how and why these young adults use pods. The participation rate for Wave 8 (the wave from which study data derive), in accordance with survey study reporting guidelines (STROBE,29 AAPOR30), was 38% (N=467 participants who initiated the survey out of 1240 who were sent electronic invitations containing survey links). Data for this study included only participants who completed the survey (N=445, 95% of those who initiated the Wave 8 survey). Identified differences in proportions of demographics between study wave and baseline due to attrition were not adjusted for since no association with outcomes of interest has been revealed in this cohort.16,3133

Statistical Analysis

Descriptive summaries included counts, means, and percentages. Standard deviations and 95% Confidence Intervals (95% CI) were created using bootstrap estimates, which accounted for school-clustering; no weighting scheme was deployed. Bootstrapping estimates the population mean from the sample by resampling with replacement and does not make any assumptions about how the data are distributed.34 Wilcoxon signed rank tests were run to assess within subject past-30-day use patterns for Juuls, non-pod-based-e-cigarettes, and cigarettes; other pod brands were not included in this analysis due to small sample size.

RESULTS

Pod (Brands) Recognition

In our sample, 85.9% (n=378) recognized Juul, 19.5% (n=86) recognized Suorin Drop, 10.2% (n=45) Myblu and 9.1% (n=40) Phix. All participants who recognized Suorin Drop, Phix, and/or Myblu also recognized Juul.

Cigarette, Non-pod-based-e-cigarette, and Pod Use

Ever-use

Rates of ever-use (non-exclusive) of any and all products were: Juul (n=115, 26.3%; 95% CI [22.4, 30.2]); cigarettes (n=105 (24%; 95% CI [20.1%, 28.1%]); non-pod-based-e-cigarettes (n=101, 23.1%; 95% CI [19.2, 27.0]); Suorin Drop (n=49, 11.2%; 95% CI [8.5, 14.2]); Phix (n=27, 6.2%; 95% CI [4.1, 8.5]); and Myblu (n=11, 2.5%; 95% CI [1.1, 4.1]) (Supplemental Table 1). Never-users of any tobacco products constituted 57.5% (n=253, 95% CI [53.0, 62.00]) of the sample. Seventy-nine participants (18.0%) (95% CI [14.5, 21.6]) reported ever-use of one product. Among participants who reported use of more than one product, n=49 (11.1%) (95% CI [8.2, 14.3]) reported use of two products, which included those who reported dual use of non-pod-based-e-cigarettes and pods; n=29 (6.6%) (95% CI [4.3, 8.9]) reported use of three tobacco products, n=14 (3.2%) (95% CI [1.6, 5.0]) four, and n=8 (1.9%) (95% CI [0.7, 3.2]) of five and n=8 (1.9%) (95% CI [0.7, 3.2]) of six products.

Post-hoc analysis revealed no difference between never-users and ever-users of any product by race, ethnicity, age, or gender. However, we found that a smaller proportion of Juul users were of Hispanic ethnicity compared to ever-users of any product (p=.04) and ever-users of e-cigarettes (p=.04; there was no difference compared to ever cigarette smokers). Compared to ever-users of any product, a smaller proportion of 17–20 year-olds reported use of e-cigarettes (p=.03) and cigarettes p=.004) and fewer 17–20 year-olds reported use of e-cigarettes (p=.03) and cigarettes (p=.002) compared to Juul.

Past 30-day Use

Past 30-day (non-exclusive) use was reported by 51.3% (n=59) of Juul ever-users, 28.6% (n=30) of cigarette smokers, 28.7% (n=29) of non-pod-based-e-cigarettes users, 57.1% (n=28) of Suorin Drop users, 37.0% (n=10) of Phix users, and 72.7% (n=8) of Myblu users. Also among past 30-day users, mean number of days used was highest for cigarettes (9.73, SD=9.89) followed by, in order, Myblu (8.63, SD=7.46), Suorin Drop (8.57, SD=9.96), Phix (7.80, SD=6.58), non-pod-based-e-cigarettes (6.83, SD=8.37), and Juul (6.15, SD=8.35).

Among participants reporting use of Juuls or non-pod-based-e-cigarettes, dual use with cigarettes was reported by N=19 (50%) of Juul users and N=12 (71%) of non-pod-based-e-cigarette users (stated another way, 79% of smokers reported dual use with Juul and 57% with non-pod-based-e-cigarettes). Dual use of Juul and non-pod-based-e-cigarettes was reported by N=15 (representing 47% of Juul users and 88% of non-pod-based-e-cigarette users). Wilcoxon signed rank tests of past 30-day use-frequency for non-exclusive use of Juul, non-pod-based-e-cigarettes, and cigarettes showed significant differences between mean number of days Juuling compared to using non-pod-based-e-cigarettes (p<.001), and between smoking and using non-pod-based-e-cigarettes (p=.033). There was no difference between Juuling and smoking cigarettes (p=.218).

First Tobacco Product Used

Among those reporting any tobacco use (N=187; 42%), cigarettes and non-pod-based-e-cigarettes were the most often reported first tobacco product used (n=48, 24.1% and n=44, 22.1%, respectively), followed by hookah (n=38, 19.1%) and Juul (n=32, 16.1%) (Supplemental Table 1). Among those reporting ever-use of pods (N=151), n=105 (70.5%) reported they had not used other types of non-pod-based-e-cigarettes before they started using pods; just n=23 (15.4%) reported they had and n=21 (14.1%) reported they “can’t remember” (n=2 had no response).

E-juice Cartridge Use

Nearly half (n=84, 43.5%) of pod ever-users indicated they were “not sure” if they used only the cartridges sold for their particular brand or if they used other types as well; n=67 (34.7%) reported they used their “brand only” and n=42 (21.5%) knew they used their devices “with other types” of cartridges. Similarly, most pod ever-users were “not sure” how long it usually takes them to finish one cartridge (n=101, 52.3%). Among those who endorsed a length of time to finish a cartridge, the largest proportion (n=45, 23.3%) reported it took them “a week (7 days)” and the smallest proportion (n=6, 3.1%) reported finishing a cartridge in “less than a day.” The remaining responses were split, in declining order of proportion, between “3–4 days” (n=18, 9.3%), “1–2 days” (n=14, 7.3%), and “5–6 days” (n=9, 4.7%).

Sharing

When pod ever-users (N=151) were asked if and how often they share their pods, half indicated they “never” share (n=76, 50.3%). Among those who did share, “sometimes” (n=23, 15.2%) was the next-most often selected frequency of sharing followed by “always” (n=20, 13.2%); “about half the time” and “often” were chosen equally by the fewest participants (n=16, 10.6% each).

Pod Descriptions

When participants who recognized one or more pod brands were asked to choose how they would describe them, Juul was most often considered a “type of vape” (n=210, 30.9%). Contrastingly, Suorin Drop was most often described as a “type of nicotine-delivery system” (n=51, 35.2%). Myblu was most often considered to be a “type of e-cigarette,” (n=25, 38.5%) and Phix had no real consensus among those familiar with it as 29.7% (n=19) each considered it “a type of nicotine delivery system” and “a type of vape” (Table 1).

Table 1.

Participant* descriptions of Juul, Suorin Drop, Phix, and Myblu e-cigarettes

Juul Myblu Phix Suorin Drop
Which best describe a (product) N Percent N Percent N Percent N Percent
A type of e-cigarette 193 28.4% 25 38.5% 16 25.0% 31 21.4%

A type of vape 210 30.9% 10 15.4% 19 29.7% 39 26.9%

A type of pod 101 14.9% 11 16.9% 9 14.1% 23 15.9%

A type of nicotine-delivery device 174 25.6% 18 27.7% 19 29.7% 51 35.2%

Other (please describe): 1 0.1% 1 1.5% 1 1.6% 1 0.7%

679 100.0% 65 100.0% 64 100.0% 145 100.0%
a

. Dichotomy group tabulated at value 1.

*

Responses (n=679) among young adults (N=437; mean age 20.1) in California, 2019

Nicotine Content

Among those who had heard of the pod brands and for all brands, the largest proportion of participants indicated “don’t know” about the amount of nicotine contained in each (Juul, n=125, 33.1%; Suorin Drop, n=27, 31.4%; Phix, n=9, 22.5%; and Myblu, n=21, 46.7%). Just 6.9% (n=26) of participants who had heard of Juul (n=375) correctly assessed Juul’s nicotine content of 59mg/ml. When comparing brands’ nicotine content to a pack of cigarettes, n=125 (33.2%) indicated “more” n=114 (30.2%) indicated “same” amount as a pack of cigaretts for Juul (n=30 (34.9%). The corresponding number were, respectively, n=20 (23.3%) for Suorin Drop, n=13 (32.5%) and n=11 (27.5%) for Phix, and n=8 (17.8%) and n=14 (31.1%) for Myblu (Table 2).

Table 2.

Reported nicotine content of e-juices and cartridges among California young adults* who recognized products prior to being surveyed; 2019

Juul (N=378) Suorin Drop (N=86) Phix (N=40) Myblu (N=45)
How much nicotine does (product) contain? N (%) N (%) N (%) N (%)
0 mg/ml 5 (1.3) 1 (1.2) 0 0
3 mg/ml 22 (5.8) 0 4 (10.0) 2 (4.4)
5 mg/ml 65 (17.2) 18 (20.9) 9 (22.5) 5 (11.1)
12 mg/ml 59 (15.6) 12 (14.0) 5 (12.5) 12 (26.7)
36 mg/ml 61 (16.1) 10 (11.6) 6 (15.0) 3 (6.7)
59 mg/ml 26 (6.9) 13 (15.1) 6 (15.0) 1 (2.2)
72 mg/ml 15 (4.0) 5 (5.8) 1 (2.5) 1 (2.2)
Don’t know 125 (33.1) 27 (31.4) 9 (22.5) 21 (46.7)
(Product) contains… Juul Suorin Drop Phix Myblu
MORE nicotine than a pack of cigarettes? 125 (33.2) 30 (34.9) 13 (32.5) 8 (17.8)
LESS nicotine than a pack of cigarettes? 68 (18.0) 11 (12.8) 2 (5.0) 7 (15.6)
SAME amount of nicotine as A pack of cigarettes? 114 (30.2) 20 (23.3) 11 (27.5) 14 (31.1)
Don’t know 70 (18.6) 25 (29.1) 14 (35.0) 16 (35.6)
*

Mean age = 20.2

Reasons for Use

There were no differences in reasons for use by brand; details regarding reasons for using pods are provided in Table 3. The largest consensus for use was 58.0% (n=112) who agreed with the statement, “I use (brand) because they’re easy to hide,” followed by 55.6% (n=105) who agreed with “The smell they produce is less obvious than other types of vapes.” Conversely, the largest overall consensus of disagreement (75%, n=144, of the sample) was with the statement, “They have less nicotine than other tobacco products,” followed by a near-tie for disagreement with the statements, “They have more nicotine than other tobacco products” (70.8%, n=136) and “They are healthier than other types of vapes” (69.4%, n=134).

Table 3.

Reasons for using pods. Responses from California young adults* reporting ever-use of pods; 2019

Easy to Hide More Nicotine Less Nicotine Less Obvious Healthier Tastier More Stylish Better Flavors
Vapor Smell
N (%) N (%) N (%) N (%) N (%) N (%) N (%) N (%) N (%)
Agree 112 (58) 59 (30.6) 48 (25.0) 95 (49.2) 105 (55.6) 56 (29.2) 94 (49.0) 88(45.8) 87 (45.3)
Disagree 81 (42) 134 (69.4) 144 (75.0) 98 (50.8) 84 (44.4) 136 (70.8) 98 (51.0) 104 (54.2) 105 (54.7)
Total 193 193 192 193 189 192 192 192 192
*

n=193; mean age 20.2

DISCUSSION

Though the evidence base is growing with respect to young adult use of pod-based e-cigarettes, and around Juul brand in particular, there are very little data on patterns of or reasons for use, or perceptions of different pod-based products among young adults. Here, we delineate reasons for use, frequency of use, sharing tendencies, understanding of nicotine content, and if and how young adults “mix and match” their pod and cartridge brands. In brief, our findings showed that most young adults who use pod-based e-cigarettes use them because they are easy to hide, use the brand Juul, are confused about how much nicotine they use, and how much nicotine is in each pod. Further, more Juul users reported past 30-day use compared to users of other e-cigarettes and users of pod-based e-cigarettes reported very little sharing tendencies. Further, there was no consensus on how pod-based e-cigarettes are referred to.

We found the average number of days using Juul mirrored that of days smoking cigarettes and that most past 30-day Juul users also used cigarettes and/or non-pod-based-e-cigarettes. These findings support reports suggesting that efficient delivery of high nicotine-levels contributes to frequency and prevalence of past 30-day use of Juul.18,19,22,23 These findings are not surprising given Juul Labs’ patent which states it’s nicotine-salt aerosolizing pod-type e-cigarettes (opposed to earlier non-pod-based-e-cigarettes that aerosolized freebase nicotine), “…provide users with nicotine levels similar to those afforded by cigarettes.”35 Studies on the Juul devices themselves have shown they emit high concentrations of protonated nicotine,36 and deliver levels of nicotine to users that is as high or higher than from cigarettes.37 These findings have many implications, including for intervention design. For example, it may be that nicotine replacement therapy will necessarily have to begin at levels equal to or higher than that of smokers, requiring longer time to titrate down.

Juul was a close runner-up for first tobacco product used and yet has only been available since 2015 (while non-pod-based-e-cigarettes have been on the US market since 200738). This fact highlights how risky Juul (and pods in general) are since it apparently has enough appeal to entice previously non-susceptible young adults to initiate and continue to use nicotine. Most Juul-using young adults had no interest in smoking cigarettes or using non-pod-type e-cigarettes and may have remained nicotine-naïve without these new pods coming on the market. Instead, they are now at risk for nicotine addiction from using these pod-type e-cigarettes that deliver nicotine to their developing brains ever-so-efficiently.16,39 Some implications here are clearly regulatory in nature. The US public health is clearly being threatened by pod-type e-cigarettes, and regulators should intervene to reduce the negative health impact by mandating warning labels, restricting access, having a nicotine standard that mandates lower levels of nicotine, and so on.

The most oft-cited detailed reasons for use reported by young adults had to do with being able to hide that they are vaping, which comports with earlier research showing “stealth” vaping as a primary reason for initiation and continued use.17,23 Reports have shown that 34% of adult e-cigarette users report stealth vaping in the past week; mostly at work, followed by bars, restaurants, and movies, conceivably to achieve a dose of nicotine where not permitted due to dependence.40 A study using prevalence and content of Youtube videos as a pr6oxy for most popular places for stealth vaping identified at school, in class, and in the school bathroom as common places among youth.41 Related Youtube videos deemed to have the most relevance were about hiding Juul: in school, from teacher, from parents, and at home41 these findings could indicate as much social pressure (e.g., hiding the behavior from those who disapprove) as dependence. These findings call for public health programming and regulation that take into account the importance of social norms in predicting behavior.

In line with earlier research showing most young adults have a general lack of understanding of the effects of nicotine dependence and addiction, here most indicated they “don’t know” how much nicotine is in the various cartridges, which could result in continued pod use.14,16,27 Ambiguous or no comprehension of product-related harm is perpetuated by, for example, the inherent vagueness of the unregulated labels on pods and other e-cigarettes (e.g., many pod brands currently list a percentage of nicotine rather than providing a specific nicotine amount). Such gaps in consumer knowledge are associated with reduced perceptions of harm and increased perceptions of benefit, resulting in increased uptake and continued use. Clearly, educational outreach and prevention programming are called for and regulators should aid these efforts by mandating clear product-labeling, including nicotine content.

Other findings also have important implications for research. First, in our study, comparable proportions of young adults reported using “brand only” and “with other types of e-juice,” which could impact our understanding of toxicant exposure and/or use patterns, especially when attempting to discern amounts of nicotine consumed. For example, a participant may indicate exclusive Juul use, and to date this closed system has only cartridges containing prespecified levels of nicotine. However, if the participant is actually using another brand of cartridges or is refilling their Juul cartridge with another brand of e-juice, and this is unknown to the researchers, any assumptions regarding nicotine or constituent exposure would be rendered moot. Second, in order to use their non-Juul choice of e-juice, the user would have to have hacked their Juul cartridge in order to open it; yet such users might not indicate this behavior on the survey, resulting in potentially misleading responses. Further and perhaps more importantly, the will to hack one’s product or alter the route of administration of drugs/drug delivery systems can be related to increased addiction-severity and lower perceptions of harm. The inability to detect the prevalence of more severe addiction and low perceptions of harm resulting from incomplete or misleading data would impede development of public-health messaging and prevention and cessation programming targeting those at high risk of using.42,43 Finally, the lack of consensus as to how pods are referred to underscores the need to include pictures or another way to identify exactly which product/s are being asked about in surveys to ensure true prevalence and actual use patterns are captured, as called for in earlier research on Juul in particular and e-cigarettes in general.10,15,16,28,44

There are some limitations to note. First, though important and reported here for the first time, too few participants reported using some brands in many instances for meaningful discussion of means or proportions in the broader context. While provided in Results, readers are cautioned to not generalize these findings beyond this sample. Where appropriate, bootstrapped SD and 95% CI were reported, providing strength to these findings. Second, this study was conducted in California, and may not be generalizable to states and countries with different tobacco control laws and rates of tobacco use. Third, participants were members of a cohort study and responses may have been affected by experimenter demand effects, defined as changes in behavior by experimental subjects due to cues about what constitutes appropriate behavior.45 However, the order of questions was randomized, which diminishes order-bias and the likelihood of demand effects. Fourth, the sample is somewhat less representative of males, and while there have been gender differences reported in the prevalence of current e-cigarette use, post-hoc analyses showed no difference between genders on outcomes of interest. Finally, in this survey, participants were not asked about feeling addicted or about their interest in quitting. Future studies should consider adding such questions to be able to understand the role of addiction in young adults perceptions and continued use of different e-cigarette products.

Findings highlight the need for regulation of e-cigarettes of all types, especially the newer pod-based systems, to protect the health and wellbeing of young adults. Findings further support regulation of packaging, especially regarding amount of nicotine; consistent use of product names in research; further research and clear information on mixing brands; and the need for clear public education campaigns addressing all manner of e-cigarettes and young adults vaping.

Supplementary Material

1

Acknowledgments

Research reported in this paper was supported by the NIH and the Food and Drug Administration (FDA) Center for Tobacco products (1P50CA180890; U54 HL147127). Additional support for KM came from NIH/National Institute on Drug Abuse (F32DA044733) and Stanford Maternal and Child Health Research Institute (1111239-440-JHACT).

Footnotes

Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

References

  • 1.Creamer MR, Wang TW, Babb S, et al. Tobacco Product Use and Cessation Indicators Among Adults — United States, 2018. Morb Mortal Wkly Rep 2019;68(45):1013–1019. doi: 10.15585/mmwr.mm6845a2 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Cullen KA, Ambrose BK, Gentzke AS, Apelberg BJ, Jamal A, King BA. Notes from the Field: Use of Electronic Cigarettes and Any Tobacco Product Among Middle and High School Students — United States, 2011–2018. Morb Mortal Wkly Rep 2018;67(45):1276–1277. doi: 10.15585/mmwr.mm6745a5 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Chaffee BW, Watkins SL, Glantz SA. Electronic Cigarette Use and Progression From Experimentation to Established Smoking. Pediatrics. 2018;141(4):e20173594. doi: 10.1542/peds.2017-3594 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Berry KM, Reynolds LM, Collins JM, et al. E-cigarette initiation and associated changes in smoking cessation and reduction: the Population Assessment of Tobacco and Health Study, 2013–2015. Tob Control. 2019;28(1):42–49. doi: 10.1136/tobaccocontrol-2017-054108 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 5.Creamer M, Case K, Loukas A, Cooper M, Perry CL. Patterns of sustained e-cigarette use in a sample of young adults. Addict Behav 2019;92:28–31. doi: 10.1016/j.addbeh.2018.12.011 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Buchanan ND, Grimmer JA, Tanwar V, Schwieterman N, Mohler PJ, Wold LE. Cardiovascular risk of electronic cigarettes: a review of preclinical and clinical studies. Cardiovasc Res 2020;116(1):40–50. doi: 10.1093/cvr/cvz256 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Alexander LEC, Perez MF. Identifying, tracking, and treating lung injury associated with e-cigarettes or vaping. The Lancet 2019;394(10214):2041–2043. doi: 10.1016/S0140-6736(19)32730-8 [DOI] [PubMed] [Google Scholar]
  • 8.Commissioner O of the. Press Announcements -Statement from FDA Commissioner Scott Gottlieb, M.D., on new enforcement actions and a Youth Tobacco Prevention Plan to stop youth use of, and access to, JUUL and other e-cigarettes. https://www.fda.gov/newsevents/newsroom/pressannouncements/ucm605432.htm. Accessed March 25, 2019.
  • 9.Surgeon General’s Advisory on E-cigarette Use Among Youth | Smoking & Tobacco Use | CDC https://www.cdc.gov/tobacco/basic_information/e-cigarettes/surgeon-general-advisory/index.html. Published April 9, 2019. Accessed December 2, 2019.
  • 10.Huang J, Duan Z, Kwok J, et al. Vaping versus JUULing: how the extraordinary growth and marketing of JUUL transformed the US retail e-cigarette market. Tob Control. May 2018:tobaccocontrol-2018-054382. doi: 10.1136/tobaccocontrol-2018-054382 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Vallone DM, Bennett M, Xiao H, Pitzer L, Hair EC. Prevalence and correlates of JUUL use among a national sample of youth and young adults. Tob Control. October 2018:tobaccocontrol-2018-054693. doi: 10.1136/tobaccocontrol-2018-054693 [DOI] [PubMed] [Google Scholar]
  • 12.Goniewicz ML, Boykan R, Messina CR, Eliscu A, Tolentino J. High exposure to nicotine among adolescents who use Juul and other vape pod systems (‘pods’). Tob Control. August 2018:tobaccocontrol-2018-054565. doi: 10.1136/tobaccocontrol-2018-054565 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Chu K-H, Colditz JB, Primack BA, et al. JUUL: Spreading Online and Offline. J Adolesc Health. 2018;63(5):582–586. doi: 10.1016/j.jadohealth.2018.08.002 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Laestadius L, Wang Y. Youth access to JUUL online: eBay sales of JUUL prior to and following FDA action. Tob Control. September 2018:tobaccocontrol-2018–054499. doi: 10.1136/tobaccocontrol-2018-054499 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Willett JG, Bennett M, Hair EC, et al. Recognition, use and perceptions of JUUL among youth and young adults. Tob Control. 2019;28(1):115–116. doi: 10.1136/tobaccocontrol-2018-054273 [DOI] [PubMed] [Google Scholar]
  • 16.McKelvey K, Baiocchi M, Halpern-Felsher B. Adolescents’ and Young Adults’ Use and Perceptions of Pod-Based Electronic Cigarettes. JAMA Netw Open. 2018;1(6):e183535–e183535. doi: 10.1001/jamanetworkopen.2018.3535 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Ramamurthi D, Chau C, Jackler RK. JUUL and other stealth vaporisers: hiding the habit from parents and teachers. Tob Control. September 2018:tobaccocontrol-2018-054455. doi: 10.1136/tobaccocontrol-2018-054455 [DOI] [PubMed] [Google Scholar]
  • 18.Jackler RK, Ramamurthi D. Nicotine arms race: JUUL and the high-nicotine product market. Tob Control. February 2019:tobaccocontrol-2018-054796. doi: 10.1136/tobaccocontrol-2018-054796 [DOI] [PubMed] [Google Scholar]
  • 19.Kavuluru R, Han S, Hahn EJ. On the popularity of the USB flash-drive shaped electronic cigarette Juul. Tob Control. 2019;28(1):110–112. doi: 10.1136/tobaccocontrol-2018-054259 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Bourdon JL, Hancock LC. Using electronic audience response technology to track e-cigarette habits among college freshmen. Addict Behav 2019;95:24–27. doi: 10.1016/j.addbeh.2019.02.019 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Boykan R, Messina CR, Chateau G, Eliscu A, Tolentino J, Goniewicz ML. Self-Reported Use of Tobacco, E-cigarettes, and Marijuana Versus Urinary Biomarkers. Pediatrics. 2019;143(5). doi: 10.1542/peds.2018-3531 [DOI] [PubMed] [Google Scholar]
  • 22.Kamerow D Start-up e-cigarette brand aims to “improve smokers’ lives”. BMJ 2018;362:k2930. doi: 10.1136/bmj.k2930 [DOI] [Google Scholar]
  • 23.Hammond D, Wackowski OA, Reid JL, O’Connor RJ. Use of JUUL E-cigarettes Among Youth in the United States. Nicotine Tob Res doi: 10.1093/ntr/nty237 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.On the popularity of the USB flash drive-shaped electronic cigarette Juul | Tobacco Control. https://tobaccocontrol.bmj.com/content/28/1/110.abstract. Accessed February 15, 2019. [DOI] [PMC free article] [PubMed]
  • 25.Gorukanti A, Delucchi K, Ling P, Fisher-Travis R, Halpern-Felsher B. Adolescents’ attitudes towards e-cigarette ingredients, safety, addictive properties, social norms, and regulation. Prev Med 2017;94:65–71. doi: 10.1016/j.ypmed.2016.10.019 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Roditis M, Delucchi K, Cash D, Halpern-Felsher B. Adolescents’ Perceptions of Health Risks, Social Risks, and Benefits Differ Across Tobacco Products. J Adolesc Health. 2016;58(5):558–566. doi: 10.1016/j.jadohealth.2016.01.012 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Roditis M, Lee J, Halpern-Felsher BL. Adolescent (Mis)Perceptions About Nicotine Addiction: Results From a Mixed-Methods Study. Health Educ Behav 2016;43(2):156–164. doi: 10.1177/1090198115598985 [DOI] [PubMed] [Google Scholar]
  • 28.Weaver SR, Kim H, Glasser AM, et al. Establishing consensus on survey measures for electronic nicotine and non-nicotine delivery system use: Current challenges and considerations for researchers. Addict Behav 2018;79:203–212. doi: 10.1016/j.addbeh.2017.11.016 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.STROBE Statement: Available checklists. https://www.strobe-statement.org/index.php?id=available-checklists. Accessed April 9, 2019.
  • 30.Standard Definitions-AAPOR https://www.aapor.org/Standards-Ethics/Standard-Definitions-(1).aspx. Accessed February 27, 2019.
  • 31.McKelvey K, Baiocchi M, Ramamurthi D, McLaughlin S, Halpern-Felsher B. Youth say ads for flavored e-liquids are for them. Addict Behav 2019;91:164–170. doi: 10.1016/j.addbeh.2018.08.029 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 32.McKelvey K, Halpern-Felsher B. Adolescent Cigarette Smoking Perceptions and Behavior: Tobacco Control Gains and Gaps Amidst the Rapidly Expanding Tobacco Products Market From 2001 to 2015. J Adolesc Health. 2017;60(2):226–228. doi: 10.1016/j.jadohealth.2016.09.025 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 33.McKelvey K, Baiocchi M, Lazaro A, Ramamurthi D, Halpern-Felsher B. A cigarette pack by any other color: Youth perceptions mostly align with tobacco industry-ascribed meanings. Prev Med Rep 2019;14. doi: 10.1016/j.pmedr.2019.100830 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Ong DC. A primer to bootstrapping; and an overview of doBootstrap. Retrieved Online Httpsweb Stanf Educlasspsych252tutorialsdoBootstrapPrimer Pdf. 2014.
  • 35.Bowen A, Xing C. Nicotine salt formulations for aerosol devices and methods thereof. December 2015. https://patents.google.com/patent/US9215895B2/en. Accessed March 12, 2019.
  • 36.Talih S, Salman R, El-Hage R, et al. Characteristics and toxicant emissions of JUUL electronic cigarettes. Tob Control. February 2019:tobaccocontrol-2018-054616. doi: 10.1136/tobaccocontrol-2018-054616 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.Reilly SM, Bitzer ZT, Goel R, Trushin N, Richie JP. Free Radical, Carbonyl, and Nicotine Levels Produced by Juul Electronic Cigarettes. Nicotine Tob Res doi: 10.1093/ntr/nty221 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 38.Barrington-Trimis JL, Urman R, Leventhal AM, et al. E-cigarettes, Cigarettes, and the Prevalence of Adolescent Tobacco Use. Pediatrics. 2016;138(2):e20153983. doi: 10.1542/peds.2015-3983 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39.Wagener TL. Will the Debate Over e-Cigarettes Start Cooling Down? JAMA Netw Open. 2018;1(8):e185945–e185945. doi: 10.1001/jamanetworkopen.2018.5945 [DOI] [PubMed] [Google Scholar]
  • 40.Yingst JM, Lester C, Veldheer S, Allen SI, Du P, Foulds J. E-cigarette users commonly stealth vape in places where e-cigarette use is prohibited. Tob Control. 2019;28(5):493–497. doi: 10.1136/tobaccocontrol-2018-054432 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 41.Ramamurthi D, Chau C, Jackler RK. JUUL and other stealth vaporisers: hiding the habit from parents and teachers. Tob Control. 2019;28(6):610–616. doi: 10.1136/tobaccocontrol-2018-054455 [DOI] [PubMed] [Google Scholar]
  • 42.Gossop M, Griffiths P, Powis B, Strang J. Severity of dependence and route of administration of heroin, cocaine and amphetamines. Br J Addict 1992;87(11):1527–1536. doi: 10.1111/j.1360-0443.1992.tb02660.x [DOI] [PubMed] [Google Scholar]
  • 43.Leavens ELS, Meier E, Brett EI, et al. Polytobacco use and risk perceptions among young adults: The potential role of habituation to risk. Addict Behav 2019;90:278–284. doi: 10.1016/j.addbeh.2018.11.003 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 44.Barrington-Trimis JL, Gibson LA, Halpern-Felsher B, et al. Type of E-Cigarette Device Used Among Adolescents and Young Adults: Findings From a Pooled Analysis of Eight Studies of 2166 Vapers. Nicotine Tob Res 2018;20(2):271–274. doi: 10.1093/ntr/ntx069 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 45.Zizzo DJ. Experimenter demand effects in economic experiments. Exp Econ 2010;13(1):75–98. doi: 10.1007/s10683-009-9230-z [DOI] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

1

RESOURCES