Age differences in electronic nicotine delivery systems (ENDS) usage motivations and behaviors, perceived health benefit, and intention to quit

Addictive Behaviors 98 (2019) 106054

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Age differences in electronic nicotine delivery systems (ENDS) usage motivations and behaviors, perceived health benefit, and intention to quit

T

⁎

Thanh-Huyen T. Vua,b, , Joy L. Hartb,c, Allison Groomb,d, Robyn L. Landryb,d, Kandi L. Walkerb,c, Aida L. Giachelloa,b, Lindsay Tompkinsb,c, Jennie Z. Mab,e, Anshula Keshb,d, Rose Marie Robertsonb,d, Thomas J. Payneb,f a

Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA American Heart Association Tobacco Regulation and Addiction Center (A-TRAC), Dallas, TX, USA c Department of Communication, University of Louisville, Louisville, KY, USA d American Heart Association, American Stroke Association, Dallas, TX, USA e Department of Public Health Sciences, University of Virginia, Charlottesville, VA, USA f Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Jackson, MS, USA b

H I GH L IG H T S

adults were more likely to vape due to flavors/friends’ use than older adults. • Young adults were more likely to use multiple flavors and vary nicotine content. • Young adults perceived less health benefit of ENDS use. • Young • Young adults only using ENDS had the lowest intention to quit using tobacco/nicotine products.

A R T I C LE I N FO

A B S T R A C T

Keywords: ENDS E-cigarettes Young adults Vaping initiation Flavors Intention to quit

Introduction: Data from comprehensive studies are sparse regarding age differences in issues related to electronic nicotine delivery systems (ENDS) usage. This study examined age differences in usage motivations and behaviors, perceived health benefit, and quit intentions in a large and diverse sample recruited online. Methods: The sample included 1,432 current ENDS users, ages 18–64, drawn from a national online survey conducted in 2016. Descriptive and multivariable analyses were used. Results: The sample included participants in the following age groups: 18–24 (17.5%), 25–34 (38.6%), 35–44 (23.3%), and 45–64 (20.7%). With multiple adjustments, the 18–24 age group was more likely to vape for reasons such as flavors or friends’ use, and to use multiple flavors and products with varying nicotine content. For example, the odds (95% CI) of vaping initiation due to flavor attraction vs. other reasons in the 18–24 age group were 1.40 (1.02–1.92), 2.73 (1.85–3.99), and 2.12 (1.41–3.18) compared to the 25–34, 35–44, and 45–64 age groups, respectively. In contrast, compared to older age groups, the 18–24 age group was less likely to use ENDS as an alternative to cigarettes or as a quitting device; they also used ENDS less frequently and perceived less health benefit of ENDS use. The 18–24 age group, especially those who had only used ENDS, had the lowest odds of likely quitting use of tobacco/nicotine products compared to other groups (lower by 44–73%). Conclusion: There were significant age differences in ENDS usage motivations and behaviors, perceived health benefit, and quit intentions.

1. Introduction The proliferation of electronic nicotine delivery systems (ENDS), including electronic cigarettes (e-cigarettes, vaping), has proven to be

one of the most contentious situations facing the tobacco control community. Although data are not yet available on the long-term health effects associated with the use of ENDS, available evidence indicates that short-term effects are evident, and that there are concerns

⁎ Corresponding author at: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, 680 N Lake Shore Drive, Suite 1400, Chicago, IL 60611, USA. E-mail address: [email protected] (T.-H.T. Vu).

https://doi.org/10.1016/j.addbeh.2019.106054 Received 3 February 2019; Received in revised form 4 July 2019; Accepted 14 July 2019 Available online 15 July 2019 0306-4603/ © 2019 Published by Elsevier Ltd.

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2.2. Measures

regarding the possibility of more serious consequences (Farsalinos et al., 2017; National Academies of Sciences E, and Medicine, 2018; Uchiyama, Ohta, Inaba, & Kunugita, 2013). Additionally, adolescents/ young adults who use ENDS are more likely than non-users to progress to traditional combustible cigarette use (Klein, 2015; Lanza, Russell, & Braymiller, 2017; Primack, Soneji, Stoolmiller, Fine, & Sargent, 2015), the consequences of which are well established (Office of the Surgeon General (US) and Office on Smoking and Health (US), 2004). Therefore, the rapid increase in ENDS use, especially in adolescents/young adults over the past few years (Office of the Surgeon General, 2016), is problematic and requires the attention of healthcare professionals, as well as public health policy makers and planners (The Surgeon General, 2019) (WHO, 2014). Numerous studies have focused on ENDS use by youth, including the assessment of motivations, preferences, perceptions (Ambrose, Rostron, Johnson, et al., 2014; Fong, Elton-Marshall, Driezen, et al., 2019; Perikleous, Steiropoulos, Paraskakis, Constantinidis, & Nena, 2018; Pokhrel, Fagan, Kehl, & Herzog, 2015), as well as the desire to quit using tobacco/nicotine products (Lee, Lee, & Cho, 2017; Park, Lee, & Min, 2017). A few studies compare young adults to older adults with regard to issues relating to ENDS use; however, these previous studies are primarily qualitative (Cooper, Harrell, & Perry, 2016; Griesbach & Platts, 2016), not comprehensive (Cooper et al., 2016; Harrell, Weaver, Loukas, et al., 2017; King, Alam, Promoff, Arrazola, & Dube, 2013; Levy, Yuan, & Li, 2017), or focused exclusively on flavor selections of ENDS or tobacco products (Dai & Hao, 2019; Soneji, Knutzen, & Villanti, 2019). Using data from a larger sample of current ENDS users with diverse socioeconomic backgrounds, we sought to determine differences with regard to ENDS usage motivations and behaviors, perceived health benefit, and the intention to quit among young and older adults. Our analyses took into account the effects of key demographics that define vulnerable populations, including age, gender, sexual orientation, race/ethnicity, and education level. In addition, a growing literature highlights the increasing prevalence of dual/poly tobacco product use (Stanton & Halenar, 2018). Thus, we included the role of traditional cigarette smoking status as well as use of other tobacco products and the intention to quit as additional influencers on our primary measures of interest.

2.2.1. ENDS use, cigarette smoking status, and other tobacco product use The definitions of current ENDS users and cigarette smoking status (current smoker, former smoker, and never smoked) have been described in previous publications (Glover et al., 2018; Ma et al., 2018) and were based on the definitions from the Population Assessment of Tobacco and Health (PATH) Study (Coleman, Rostron, Johnson, et al., 2017). In short, if participants used an ENDS device within the past 30 days and used for more than 3 months, they were considered current ENDS users. For cigarette smoking status, current smokers were those who smoked in the past 30 days and smoked 100 cigarettes or more in their lifetime; former smokers were those who had smoked 100 cigarettes or more in their lifetime but who had not smoked in the past 30 days; and non-smokers were those who never smoked or smoked fewer than 100 cigarettes in their lifetime and had not smoked in the past 30 days. For other types of tobacco products, including pipe, little cigar, large cigar, smokeless tobacco, and hookahs, those who had used any such products within the past 30 days were considered as current users of that product(s). 2.2.2. ENDS use motivations and behaviors 2.2.2.1. Information on primary reasons for vaping initiation. Participants were asked, “What was the primary reason you started using your vaping device (select up to 3)?” An answer of yes or no was required for each reason. 2.2.2.2. Type and number of e-liquid flavors typically used. Participants were asked, “What is the e-liquid flavor you typically buy?” Options were: no flavor, tobacco, mint/menthol, fruit, candy, sweet, coffee/chocolate, and other; participants were asked to select all options that applied. The number of flavor preferences were tallied for each participant, then categorized into 3 groups: 0–1 flavor (reference), 2 flavors, and ≥3 flavors. 2.2.2.3. Number of vaping uses per day. Participants were asked, “How often do you use your vaping device?” The number of reported uses per day was classified into 4 categories: ≤1 use only (reference group), 2–3 uses, 4–9 uses, and 10+ uses.

2. Methods

2.2.2.4. Amount of nicotine in the e-liquid used. Participants were also asked, “What is the typical nicotine content of your e-liquid?” Options were: please specify, it varies, and don’t know. Participants indicating a specific value were considered the reference group to compare against other responses.

2.1. Study sample Information on the study sample has been published (Glover, Ma, Kesh, et al., 2018; Ma, Hart, Walker, et al., 2018). Briefly, between June and August 2016, a market research company on behalf of the American Heart Association Tobacco Regulation and Addiction Center (ATRAC) fielded an online survey, recruiting three participant groups: current ENDS users, current users of other tobacco products, and individuals who had experimented with ENDS or other tobacco products. Informed consent was obtained from all participants before data were collected. The survey instrument was developed, in part, to assess ENDS users’ behaviors and motivations for use, perceptions of benefits of ENDS use, and intention to quit using tobacco/nicotine products. A total of 2,561 US adults ages 18–64 participated in the survey. A quota sampling method was used with quotas set for key demographic characteristics such as age, gender, and race/ethnicity to ensure sample diversity and allow comparison analyses by those key factors. In this study, we utilized data on current ENDS users (N=1,432). The study was approved by the institutional review board at the University of Mississippi Medical Center, where data were processed and stored in REDCap.

2.2.3. Perceived health benefit of ENDS use Participants were asked, “To what extent are the factors below a benefit of using e-cigarettes or other vaping devices?” The list of factors included: health reasons, smell, taste, price, accepted by my family and friends, accepted by society, and can vape in more places. For each factor, there were 4 response options: no benefit, a little benefit, moderate benefit, and major benefit. For this study, we examined participants’ rating of their perceived “health reasons” as a benefit of ENDS use, and ultimately re-categorized responses to be no benefit, little/moderate benefit, and major benefit. 2.2.4. Perceived addiction levels of tobacco or vaping use Current cigarette smokers or other tobacco product users were asked, “Do you believe you are addicted to or dependent upon tobacco use?” Response options were: very much, somewhat, slightly, and no. Similarly, options were provided for current vapers with the question “Do you believe you are addicted to or dependent upon vaping?” We intergrated the answers from both questions and categorized the addiction levels into 3 groups: 1) addicted very much to tobacco or vaping; 2) somewhat/slightly addicted, and 3) not addicted (reference group). 2

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2.2.5. Intention to quit using any form of tobacco/nicotine products Participants were asked “If you are using any form of tobacco or other nicotine product now, how much do you want to quit?” with the level of intention ranging from 0 to 10 (0 = not at all, 10 = very much). The rating ≥6 was classified as high intention to quit, vs. ratings < 6 as low intention.

Table 1 Descriptive characteristics by age group. Variablea

Characteristics N Gender: female Race/ethnicity Non-Hispanic White Non-Hispanic Black Hispanic Sexual orientation LGBTQ Education level No high school diploma or GED certificate Income < $50,000 Cigarette smoking statusc Current smoker Former smoker Never smoked Any other tobacco product used Tobacco/vaping addiction level Not addicted Somewhat/slightly addicted Very much addicted

2.2.6. Socio-demographic characteristics Participants were categorized by age groups (18–24, 25–34, 35–44, and 45–64), sex (female or male), race/ethnicity (non-Hispanic White, non-Hispanic Black, and Hispanic), sexual orientation (heterosexual vs. other), education level (high school graduate with diploma or higher vs. other), and annual household income level ($50,000 or more vs. less than $50,000). 2.3. Statistical analysis Descriptive statistics were conducted for the entire sample and stratified by age-groups. Chi-square tests were used for categorical variables and F-tests were used for continuous variables to compare differences in proportions or means across age groups. In multivariable analyses, the odds of ENDS use motivations and behaviors, perceived ENDS health benefit, and intention to quit were compared between the youngest age group and the older age groups. For dichotomized dependent variables, logistic regression models were employed; for categorical variables, multinomial logistic regression models were used. In addition, the odds of intention to quit were further estimated by age group and cigarette smoking status. All models were adjusted for sex, race/ethnicity, sexual orientation, education level, and income level. In addition, models were further adjusted for current cigarette smoking status and other tobacco product use to explore whether dual or poly product use affected the associations of age differences and use behaviors, motivation, perceived health benefit and intention to quit. Moreover, we also investigated the effect of levels of addiction on the association of interest (except for models on the motivation of use initiation). All analyses were conducted using SAS version 9.4 (SAS Institute Inc, Cary, NC).

Total

P-valueb

Age group 18–24

25–34

35–44

45–64

1,432 50.0

250 61.6

553 54.1

333 45.7

296 39.5

22.8 22.9 54.3

5.6 20.8 73.6

14.8 23.2 62.0

24.0 24.0 52.0

50.7 23.0 26.4

17.3

28.8

17.9

13.5

10.5

8.3

14.4

7.8

7.2

5.4

41.0

63.2

41.2

30.0

34.1

35.4 37.1 27.5 43.8

27.6 16.8 55.6 62.0

39.8 30.6 29.7 49.4

39.9 43.2 16.8 36.6

28.7 59.5 11.8 26.0

< .001 < .001

< .001 < .001

< .001 < .001

< .001 < .001

26.8 47.2

40.0 39.2

26.4 45.6

19.2 52.9

25.0 50.7

26.0

20.8

28.0

27.9

24.3

Abbreviations: LGBTQ: Lesbian, gay, bisexual, transgender, or queer; GED: General Education Development. a Numbers are % unless otherwise indicated. b P-values for comparison across age groups based on χ2 test. c Current smoker: smoked in the past 30 days and smoked ≥100 cigarettes in lifetime; former smoker: smoked ≥100 cigarettes or more in lifetime but had not smoked in the past 30 days; non-smokers: never smoked or smoked < 100 cigarettes in lifetime and had not smoked in the past 30 days. d Other tobacco products included pipe, little cigar, large cigar, smokeless tobacco, and hookahs.

The proportion reporting tobacco flavor use was lowest in the youngest age group compared to older age groups (16.4% vs. 21.9–29.1%). In contrast, the proportions reporting fruit, candy, or sweet flavor use were higher in the youngest age group compared to older age groups. For example, fruit was the most common flavor in the 18–24 age group (57.2%) vs. 29.4–47.0% in older age groups. The proportion reporting use of the mint/menthol flavor in the 18–24 age group was lower than in the 25–34 and 35–44 age groups, but was higher than in the 45–64 age group. More than one-half of the study sample reported using varied nicotine amounts in their e-liquid, and the proportion endorsing this option was highest in the 18–24 age group (59.2%). The 18–24 age group was also more likely to report ≤1 use of ENDS per day. Only 18% perceived no health benefit in using ENDS. The proportion perceiving no health benefit in the 18–24 age group was highest compared to other age groups. All age groups were more likely to indicate a moderate intention to quit any form of tobacco/nicotine product, with the 18–24 age group having the lowest mean of intention to quit compared to the older age groups (p=0.014). With adjustment for sex, race/ethnicity, education level, sexual orientation, and income level, the youngest age group’s reasons for vaping initiation remained significantly different from the older age groups. As shown in Table 3, the youngest age group was more likely to start vaping due to flavor attraction or friends’ use compared to older age groups. For example, the odds (95% CI) of vaping initiation due to flavor attraction in the 18–24 age group was 1.40 (1.02–1.92), 2.73 (1.85–3.99), and 2.12 (1.41–3.18) compared to the 25–34, 35–44, and 45–64 age groups, respectively. In contrast, the 18–24 age group was less likely to use ENDS as an alternative to cigarettes, for the nicer

3. Results As shown in Table 1, of 1,432 current ENDS users, 17.5% were 18–24 years old, 38.6% were 25–34, 23.3% were 35–44, and 20.7% were 45–64. As a result of quotas set for key demographic characteristics, about one half of current ENDS users were female or Hispanic. Also 17.3% were LGBTQ; 8.3% did not have a high school diploma or higher; and 41% had an annual household income of less than $50,000. Current cigarette smokers comprised 35.4% of the sample, and 27.5% never smoked cigarettes. Compared to the older age groups, the youngest age group had a higher proportion of females, Hispanics, those who identified as LGBTQ, those with less education, lower income persons, non-cigarette smokers, other tobacco product users, and those reporting no addiction to tobacco or vaping. Results from descriptive analyses are shown in Table 2. The main reasons to start vaping were: alternative to cigarette smoking (43.4%), healthier than other products (31.9%), flavor attraction (29.9%), nicer smell than tobacco smoke (19.1%), and trying to quit cigarettes or other tobacco products (18.8%). About 4% reported they started vaping based on a recommendation of a healthcare professional. There were significant differences in the main reasons for vaping initiation by age group, with the 18–24 year olds having the highest reported proportion to begin vaping because of the flavors, appeal of new products, or friends’ use, but also having the lowest proportion to report alternative to cigarettes, healthcare professional recommendation, price, or trying to quit cigarettes (all p’s < 0.05). The most common flavor used was fruit (43.1%), followed by mint/ menthol (30.2%), sweet (29.9%), candy (24.8%), and tobacco (23.3%). 3

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groups, respectively. The odds of believing ENDS provide a major health benefit in the youngest groups was lower by 35–52% when compared to the older age groups. However, the comparison between the youngest and the oldest age groups was not statistically significant. The odds of high intention to quit using tobacco/nicotine products was also significantly lower in the 18–24 age group compared to the older age groups, especially when compared to the 25–34 or 35–44 age groups. With further adjustments for cigarette smoking status and other tobacco product use, the associations of age differences and ENDS usage motivation and behaviors and intention to quit were attenuated compared to the associations found in initial models but remained significant (except for the model of perceived health benefit). For example, the odds (95% CI) of using ≥3 vs. 0–1 flavors in the 18–24 age group compared to the 25–34, 35–44, and 45–64 age groups were 1.48 (1.04–2.12), 2.03 (1.33–3.11), and 3.43 (2.10–5.62), respectively. However, for the model of perceived health benefit, further adjusting for cigarette smoking status and other tobacco product use, the association was no longer statistically significant, although still provided a similar trend. Adding the levels of addiction to tobacco/vaping products into the models had no significant impact on the associations of interest (data not shown in tables). With further consideration of the cigarette smoking status (Fig. 1), the odds of high intention to quit in the 18–24 age group and those who never smoked cigarettes was significantly lower than in all other age/ smoking status groups (lower by 44–78%), except when compared to the never smoked cigarette and older age groups. Adding other tobacco product use and the levels of addiction into the model did not influence the above associations.

Table 2 Descriptive analyses of ENDS use motivations and behaviors, perceived health benefit, and intention to quit by age group. Variablea

Reasons for vaping initiation Just an alternative to cigarettes Healthier than other products Nicer smell than tobacco smoke I like the flavors My friends vape I’m a cloud chaser – I like big clouds A healthcare professional recommended it Cheaper than other tobacco products I like trying new products Trying to quit smoking cigarettes or other tobacco products Other reasons Flavors typically use Tobacco Mint/menthol Fruit Candy Sweet Coffee/chocolate Other flavors Amount of nicotine in eliquid Specific amount Varied amount Did not know amount Number of vaping uses per day ≤1 use 2-3 uses 4–9 uses 10+ uses Perceived health benefit of ENDS use No benefit Little/moderate benefit Major benefit Intention to quitc (mean)

Total

P-valueb

Age group 18–24

25–34

35–44

45–64

43.4

33.2

47.0

48.1

40.2

< .001

31.9

32.4

30.7

33.9

31.4

.793

19.1

16.8

23.5

17.7

14.2

.005

29.9 8.4 4.8

40.8 17.2 1.08

33.8 8.0 4.9

20.7 6.6 3.3

23.7 3.7 1.4

< .001 < .001 < .001

3.8

2.4

3.1

3.0

7.1

.009

7.7

4.0

5.6

10.2

11.8

< .001

7.5 18.8

10.8 7.6

8.5 15.9

3.9 21.3

6.7 30.7

.011 < .001

2.6

1.6

2.2

0.9

6.1

< .001

23.3 30.2 43.1 24.8 29.9 12.4 4.4

16.4 28.0 57.2 39.2 36.4 13.2 2.8

21.9 33.8 47.0 27.9 32.4 12.3 4.0

25.8 30.9 38.1 20.1 30.3 14.7 4.5

29.1 24.3 29.4 12.2 19.3 9.5 6.4

.003 .030 < .001 < .001 < .001 .247 .201 < .001

23.5 52.7 24.2

18.0 59.2 22.8

21.0 56.6 22.4

27.0 51.4 21.6

28.7 39.9 31.4

4. Discussion This study surveyed a national sample of 1,432 current ENDS users aged 18–64 with diverse socio-demographic backgrounds. After controlling for multiple factors, the youngest (18–24) age group was more likely to start vaping due to flavor attractions or friends’ use, and to use multiple flavors, and products with varying nicotine content. Additionally, this youngest group was less likely to use ENDS as an alternative to cigarettes or because they were trying to quit smoking cigarettes or other tobacco products. The youngest group reported fewer ENDS uses per day, and perceived less health benefit of ENDS use. This youngest group, especially those who had never smoked cigarettes, also rated a lower intention to quit any form of tobacco/nicotine product than all other groups. Our findings support results from previous studies and expand understanding of age differences in ENDS usage motivation and behaviors, perceived health benefit, and the intention to quit by considering the influence of key socio-demographic factors as well as cigarette smoking status, other tobacco product use, and levels of addiction. Consistent with results from previous studies, we identified the importance of flavor attraction in ENDS use by youth (Cooper et al., 2016; Dai & Hao, 2019; Harrell, Weaver, et al., 2017; McKeganey, Barnard, & Russell, 2018; Office of the Surgeon General, 2016; Soneji et al., 2019; Villanti, Johnson, Ambrose, et al., 2017) as well as having friends who vape (McKeganey et al., 2018). For example, Harrell et al.(Harrell, Weaver, et al., 2017) examined flavored ENDS use in youth (12–17 years old), young adults (18–29 years old), and older adults (30+ years old), noting that flavors were an important reason to use ENDS. Fruit-flavor use predominated for all age groups, and was highest among youth/ young adults compared to older adults (Soneji et al., 2019), followed by candy/dessert flavors (Harrell, Weaver, et al., 2017; Morean, Butler, Bold, et al., 2018). The use of multiple flavors was also found to differ by age, with more numerous flavors used by adults (18+ years old) compared to adolescents (Morean et al., 2018). In analyses of pastmonth ENDS users in Wave 2 of the Population Assessment for Tobacco and Health (PATH) study, adolescents and young adults were more

< .001 25.5 20.4 26.6 27.5

36.9 19.3 27.1 16.8

22.7 23.1 27.8 26.4

24.6 16.7 26.4 32.4

22.3 20.6 24.3 32.9 .010

18.0 49.5 32.5 6.5

26.0 46.8 27.2 5.9

16.8 51.9 31.3 6.6

15.3 48.7 36.0 6.8

16.2 48.3 35.5 6.4

.014

a

Numbers are % unless otherwise indicated. P-values for comparison across age groups based on χ2 test or F test. c Intention to quit using any tobacco/nicotine products, ranging from 0-10 scale where 0 is not at all and 10 is very much. b

smell, or as a quitting device. For example, the odds of vaping initiation due to trying to quit smoking cigarettes or other tobacco products was lower in the 18–24 age group by 60%, 73%, and 80% when compared to the 25–34, 35–44, and 45–64 age groups, respectively. Regarding ENDS use behaviors, the 18–24 age group was more likely to use multiple flavors and varied nicotine content compared to the older age groups, especially when comparing ≥3 vs. 0–1 flavors. For example, the odds (95% CI) of using ≥3 vs. 0–1 flavors in the 18–24 age group compared to the 25–34, 35–44, and 45–64 age groups were 1.44 (1.02–2.04), 2.00 (1.34–3.00), and 3.49 (2.18–5.56), respectively. The 18–24 age group was also more likely to report using varied nicotine content than a specific content, particularly when compared to the 45–64 age group. On the other hand, the 18–24 age group was less likely to report using ENDS more frequently or to believe ENDS provide any health benefit. For example, the odds of reporting 10+ uses per day vs. ≤1 use in the 18–24 age group was lower by 62%, 65%, and 59% when compared to the 25–34, 35–44, and 45–64 age 4

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Table 3 Adjusteda odds ratios (95% CI) of ENDS usage motivations and behaviors, perceived health benefit, and intention to quit selected by age group. Variables

Motivations Primary reason for vaping initiation Just an alternative to cigarettes vs. other reasonsb Nicer smell than tobacco smoke vs. other reasonsb I like the flavors vs. other reasonsb My friends vape vs. other reasonsb Trying to quit smoking cigarettes or other tobacco products vs. other reasonsb Usage behaviors Number of flavors usedc 0–1 flavor (referent) Used 2 flavors vs. 0–1 flavor Used ≥3 flavors vs. 0–1 flavor Nicotine content of e-liquidc Using a specific content (referent) Varied content Don’t know Number of vaping uses per dayc ≤1 use only (referent) 2–3 uses 4–9 uses 10+ uses Perceived health benefit of ENDS usec No benefit (referent) Little/moderate benefit Major benefit Intention to quitd Likely vs. less likely a b c d

Age-group comparisons 18–24 vs. 25–34

18–24 vs. 35–44

18–24 vs. 45–64

0.60 0.64 1.40 2.66 0.40

0.59 0.89 2.72 3.32 0.27

0.82 1.16 2.12 5.30 0.20

(0.43–0.82) (0.43–0.95) (1.02–1.92) (1.66–4.26) (0.23–0.68)

(0.41–0.84) (0.57–1.40) (1.85–3.99) (1.86–5.90) (0.16–0.48)

(0.56–1.20) (0.70–1.92) (1.41–3.18) (2.52–11.15) (0.11–0.36)

1.00 1.16 (0.75–1.81) 1.44 (1.02–2.04)

1.00 1.14 (0.70–1.87) 2.00 (1.34–3.00)

1.00 1.95 (1.11–3.41) 3.49 (2.18–5.56)

1.00 1.30 (0.87–1.96) 1.20 (0.74–1.93)

1.00 1.87(1.20–2.92) 1.55(0.92–2.62)

1.00 2.09 (1.28–3.39) 0.91 (0.53–1.57)

1.00 0.52 (0.34–0.81) 0.58 (0.39–0.88) 0.38 (0.24–0.60)

1.00 0.79 (0.47–1.32) 0.66 (0.42–1.04) 0.35 (0.21–0.57)

1.00 0.58 (0.34–0.99) 0.67 (0.40–1.12) 0.41 (0.24–0.71)

0.62 (0.42–0.92) 0.58 (0.38–0.90)

0.64 (0.40–1.01) 0.48 (0.29–0.79)

0.78 (0.47–1.27) 0.65 (0.38–1.10)

0.62 (0.45–0.85)

0.56 (0.39–0.81)

0.73 (0.50–1.08)

Adjusted for sex, race/ethnicity, education level, sexual orientation, and income level. Logistic regression was used. Multinomial logistic regression was used. Intention to quit using any form of tobacco/nicotine products: likely to quit (≥6 out of 0–10 scale) vs. less likely to quit (< 6 out of 0–10 scale).

likely to use multiple flavor types than older adults (Soneji et al., 2019). Regarding the number of uses per day, a graded positive association between age and the frequency of ENDS use was found in a previous investigation among 6,656 participants in the Korean Youth Risk Behavior Web-Based Survey. However, this study sample was restricted to adolescent students (Lee et al., 2017). Our study, with a focus on adults, from young adulthood to older age, revealed that the young adult group had a lower frequency of ENDS use than older age groups. In terms of the amount of nicotine in the e-liquid use, to our knowledge, no previous study addressed age differences in nicotine

strength. Given that the amount of nicotine in e-liquid varies among ENDS brands/products (Goniewicz, Kuma, Gawron, Knysak, & Kosmider, 2013; Schroeder & Hoffman, 2014), our finding that the youngest group was more likely to use products of varied nicotine strengths seems likely to be a function of experimentation. Although previous studies have found that ENDS users commonly perceive ENDS as less harmful than conventional cigarettes (Cooper et al., 2016; Dawkins, Turner, Roberts, & Soar, 2013; Goniewicz, Lingas, & Hajek, 2013), these studies did not aim to explore age differences in the health risk perceptions of ENDS use and/or were based Fig. 1. Adjusteda odds ratiosb (95% CI) of likely to quit using tobacco/nicotine products by age group and cigarette smoking status. a Adjusted for sex, race/ethnicity, education level, sexual orientation, and income level. b Odds ratios of likely to quit (≥6 out of 0–10 scale) of the age 18–24 and never smoked cigarettes group compared to other age/smoking status groups.

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Role of funding sources

on qualitative analyses. A recent study using Wave 1 PATH data, which included 32,320 adults aged 18 years and older, also found that younger adults were more likely to say ENDS were less harmful compared to cigarettes than older adults; however, this study did not examine age differences in the perceived harmfulness of ENDS among END users (Fong et al., 2019). Our study did not assess perceived health benefit of ENDS relative to cigarettes/other tobacco products. Instead, we found among ENDS users, there were age differences in perceived health benefit of ENDS use. Our study also found that the association of age differences and perceived health benefit of ENDS use were attenuated by cigarette smoking status and other tobacco product use of the participants. This finding is consistent with the finding that using dual and/or poly tobacco/nicotine products was associated with perceived health risks (Leavens, Meier, Brett, et al., 2019). In terms of the intention to quit any form of tobacco/nicotine product, Nayak, Pechacek, Weaver, & Eriksen, 2016 analyzed 1,014 current cigarette smokers and 248 dual users of ENDS and traditional cigarettes. Their results showed no age differences in the high intention to quit in both dual users as well as the overall sample. However, this study also examined attempts to quit and found that, among dual users, those age > 55 years old were less likely to have attempted to quit smoking than those age 18–34 [adjusted OR (95%CI) was 0.43 (0.20–0.96)] (Nayak et al., 2016). The current study focused on current ENDS users while taking into account the participants’ cigarette smoking status. We were able to determine that the young adult group, especially those who had never smoked cigarettes, had the lowest intention to quit using tobacco/nicotine products than all other groups, even after adjusting for other tobacco product use. This study has several limitations. As this investigation employed an online panel of participants, these individuals may differ demographically and by other characteristics from those recruited in-person. Also, the data were cross-sectional, limiting the nature of analyses we were able to conduct. Further, consistent with similar studies, self-reported data could be subject to potential recall and reporting biases. Despite this concern, the use of such survey methodology has been validated in previous studies and is viewed as yielding valuable findings (Haddock, Lando, Pyle, et al., 2005; Harrell, Loukas, Jackson, Marti, & Perry, 2017). In addition, our sample was deliberately non-random to assure adequate representation of specific characteristics across vulnerable populations such as age, race, ethnicity, income, and sexual orientation. Thus, our findings cannot be generalized to the larger U.S. population. However, our study permitted an examination on ENDS use while taking into account key demographic influences on our association of interest. In conclusion, our findings demonstrate that there are significant differences among age groups in ENDS usage motivations and behaviors, perceived health benefit, and the intention to quit tobacco/nicotine products. Because young adults are attracted to flavors, especially fruit flavors, our findings support the FDA consideration of a ban on flavors. Another option would be restrictions on the advertisement of ENDS products with flavors, particularly in venues targeting youth and young adults (Department of Health and Human Services, 2018). Because young adults tend to use products with varying nicotine content in their e-liquids, we support the FDA current considerations to lower the amount of nicotine in ENDS products as a means to lessening the potential for addiction in young adults. This consideration may be especially important because young adults indicated less intention to quit using ENDS. Our findings also support the FDA strategic research priority on public education with an age-difference focus as well as the WHO Framework Convention on Tobacco Control (WHO-FCTC) recommendation on regulations to “impede ENDS promotion and prevent uptake by youth; minimize potential health risks to ENDS users and non-users; prohibit unproven health claims from being made about ENDS”(WHO, 2014).

This research was supported via Tobacco Centers of Regulatory Science (TCORS) grant P50HL120163 awarded to the American Heart Association by the National Heart, Lung, and Blood Institute of the National Institutes of Health and FDA Center for Tobacco Products. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Food and Drug Administration. Contributors All authors contributed to the development and implementation of the survey of adult vaping. Dr. Vu was responsible for designing the study, conducting the data analysis and preparing the manuscript. Dr. Payne provided significant suggestions and revisions. All authors provided feedback and suggestions throughout the writing process. Declaration of Competing Interest All authors declare that they have no conflicts of interest. References Ambrose, B. K., Rostron, B. L., Johnson, S. E., et al. (2014). Perceptions of the relative harm of cigarettes and e-cigarettes among U.S. youth. American Journal of Preventive Medicine, 47(2 Suppl 1), S53–S60. Coleman, B. N., Rostron, B., Johnson, S. E., et al. (2017). Electronic cigarette use among US adults in the Population Assessment of Tobacco and Health (PATH) Study, 2013–2014. Tobacco Control, 26(e2), e117–e126. Cooper, M., Harrell, M. B., & Perry, C. L. (2016). Comparing young adults to older adults in e-cigarette perceptions and motivations for use: implications for health communication. Health Education Research, 31(4), 429–438. Dai, H., & Hao, J. (2019). Flavored tobacco use among U.S. adults by age group: 20132014. Substance Use & Misuse, 54(2), 315–323. Dawkins, L., Turner, J., Roberts, A., & Soar, K. (2013). 'Vaping' profiles and preferences: An online survey of electronic cigarette users. Addiction, 108(6), 1115–1125. Department of Health and Human Services. The FDA's public comment on regulation of flavors in tobacco products. (2018). https://sc.cnbcfm.com/applications/cnbc.com/ resources/editorialfiles/2018/03/20/cigs.pdf Assessed by December 9, 2018. Farsalinos, K. E., Kistler, K. A., Pennington, A., Spyrou, A., Kouretas, D., & Gillman, G. (2017). Aldehyde levels in e-cigarette aerosol: Findings from a replication study and from use of a new-generation device. Food and Chemical Toxicology, 111, 64–70. Fong, G. T., Elton-Marshall, T., Driezen, P., et al. (2019). U.S. adult perceptions of the harmfulness of tobacco products: descriptive findings from the 2013-14 baseline wave 1 of the path study. Addictive Behaviors, 91, 180–187. Glover, L. M., Ma, J. Z., Kesh, A., et al. (2018). The social patterning of electronic nicotine delivery system use among US adults. Preventive Medicine, 116, 27–31. Goniewicz, M. L., Kuma, T., Gawron, M., Knysak, J., & Kosmider, L. (2013). Nicotine levels in electronic cigarettes. Nicotine & Tobacco Research, 15(1), 158–166. Goniewicz, M. L., Lingas, E. O., & Hajek, P. (2013). Patterns of electronic cigarette use and user beliefs about their safety and benefits: an internet survey. Drug and Alcohol Review, 32(2), 133–140. Griesbach, D., & Platts, A. (2016). Young adults and e-cigarettes: A qualitative exploration of awareness, experience and attitudes. Scottish Government. Haddock, C. K., Lando, H. A., Pyle, S. A., et al. (2005). Prediction of adult-onset smoking initiation among U.S. Air force recruits using the pierce susceptibility questionnaire. American Journal of Preventive Medicine, 28(5), 424–429. Harrell, M. B., Loukas, A., Jackson, C. D., Marti, C. N., & Perry, C. L. (2017). Flavored tobacco product use among youth and young adults: What if flavors didn't exist? Tobacco Regulatory Science, 3(2), 168–173. Harrell, M. B., Weaver, S. R., Loukas, A., et al. (2017). Flavored e-cigarette use: Characterizing youth, young adult, and adult users. Preventive Medical Reports, 5, 33–40. King, B. A., Alam, S., Promoff, G., Arrazola, R., & Dube, S. R. (2013). Awareness and everuse of electronic cigarettes among U.S. adults, 2010-2011. Nicotine & Tobacco Research, 15(9), 1623–1627. Klein, J. D. (2015). Electronic cigarettes are another route to nicotine addiction for youth. JAMA Pediatrics, 169(11), 993–994. Lanza, S. T., Russell, M. A., & Braymiller, J. L. (2017). Emergence of electronic cigarette use in US adolescents and the link to traditional cigarette use. Addictive Behaviors, 67, 38–43. Leavens, E. L. S., Meier, E., Brett, E. I., et al. (2019). Polytobacco use and risk perceptions among young adults: The potential role of habituation to risk. Addictive Behaviors, 90, 278–284. Lee, J. A., Lee, S., & Cho, H. J. (2017). The relation between frequency of e-cigarette use and frequency and intensity of cigarette smoking among South Korean adolescents.

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T.-H.T. Vu, et al.

Perikleous, E. P., Steiropoulos, P., Paraskakis, E., Constantinidis, T. C., & Nena, E. (2018). E-cigarette use among adolescents: An overview of the literature and future perspectives. Frontiers in Public Health, 6, 86. Pokhrel, P., Fagan, P., Kehl, L., & Herzog, T. A. (2015). Receptivity to e-cigarette marketing, harm perceptions, and e-cigarette use. American Journal of Health Behavior, 39(1), 121–131. Primack, B. A., Soneji, S., Stoolmiller, M., Fine, M. J., & Sargent, J. D. (2015). Progression to traditional cigarette smoking after electronic cigarette use among US adolescents and young adults. JAMA Pediatrics, 169(11), 1018–1023. Schroeder, M. J., & Hoffman, A. C. (2014). Electronic cigarettes and nicotine clinical pharmacology. Tobacco Control, 23(Suppl. 2), ii30–35. Soneji, S. S., Knutzen, K. E., & Villanti, A. C. (2019). Use of flavored e-cigarettes among adolescents, young adults, and older adults: Findings from the population assessment for tobacco and health study. Public Health Reports, 134(3), 282–292. Stanton, C. A., & Halenar, M. J. (2018). Patterns and correlates of multiple tobacco product use in the United States. Nicotine & Tobacco Research, 20(suppl_1), S1–S4. The Surgeon General. The call to action on e-cigarette use among youth and young adults. (2013). https://www.cdc.gov/tobacco/data_statistics/sgr/e-cigarettes/pdfs/2016_ SGR_The_Call-508.pdf Assessed November 17, 2017. Uchiyama, S., Ohta, K., Inaba, Y., & Kunugita, N. (2013). Determination of carbonyl compounds generated from the E-cigarette using coupled silica cartridges impregnated with hydroquinone and 2,4-dinitrophenylhydrazine, followed by highperformance liquid chromatography. Analytical Sciences, 29(12), 1219–1222. Villanti, A. C., Johnson, A. L., Ambrose, B. K., et al. (2017). Flavored tobacco product use in youth and adults: findings from the first wave of the PATH study (2013–2014). American Journal of Preventive Medicine, 53(2), 139–151. WHO (2014). Electronic nicotine delivery systems and electronic non-nicotine delivery systems. Framework convention on tobacco controlhttp://appswhoint/gb/fctc/PDF/ cop6/FCTC_COP6(9)-enpdf.

International Journal of Environmental Research and Public Health, 14(3). Levy, D. T., Yuan, Z., & Li, Y. (2017). The prevalence and characteristics of e-cigarette users in the U.S. International Journal of Environmental Research and Public Health, 14(10). Ma, J. Z., Hart, J. L., Walker, K. L., et al. (2018). Perceived health risks of electronic nicotine delivery systems (ENDS) users: The role of cigarette smoking status. Addictive Behaviors, 91, 156–163. McKeganey, N., Barnard, M., & Russell, C. (2018). Vapers and vaping: E-cigarettes users views of vaping and smoking. Drugs: Education, Prevention and Policy, 25(1), 13–20. Morean, M. E., Butler, E. R., Bold, K. W., et al. (2018). Preferring more e-cigarette flavors is associated with e-cigarette use frequency among adolescents but not adults. PLoS One, 13(1), e0189015. National Academies of Sciences E, and Medicine. Public health consequences of e-cigarettes. (2018). Available at: https://wwwnapedu/resource/24952/ 012318ecigaretteConclusionsbyEvidencepdf Accessed Jan 25, 2019 . Nayak, P., Pechacek, T. F., Weaver, S. R., & Eriksen, M. P. (2016). Electronic nicotine delivery system dual use and intention to quit smoking: Will the socioeconomic gap in smoking get greater? Addictive Behaviors, 61, 112–116. Office of the Surgeon General (2016). E-cigarette use among youth and young adults: A report of the surgeon general. U.S. Department of Health and Human Services. Available from https://e-cigarettes.surgeongeneral.gov/documents/2016_sgr_full_report_non-508. pdf. Office of the Surgeon General (US); Office on Smoking and Health (US). The health consequences of smoking: A report of the surgeon general. Atlanta (GA): Centers for Disease Control and Prevention (US); Available from: https://www.ncbi.nlm.nih. gov/books/NBK44695/. 2004. Park, S., Lee, H., & Min, S. (2017). Factors associated with electronic cigarette use among current cigarette-smoking adolescents in the Republic of Korea. Addictive Behaviors, 69, 22–26.

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