## INTRODUCTION

The study of electronic nicotine delivery systems (ENDS) use among young individuals is important for many reasons. First, ENDS use has been associated with many short-term health conditions affecting several organ systems, including the respiratory and cardiovascular systems, as well as mental health conditions such as depression1,2. Secondly, ENDS contain widely varying levels of nicotine and have been associated with subsequent cigarette smoking and other risky health behaviors including use of non-prescription drugs, marijuana, and heavy alcohol3,4. Most importantly, although promoted as a tobacco-cessation tool, population surveillance has shown significant use among young tobacco naïve individuals, many of whom report frequent use5.

Of particular concern are the rapidly changing design and the innovation of new ENDS products that continue to be introduced into the market. Podbased e-cigarettes, also known as pod-mods, were introduced onto the market in 2015 and quickly became the dominant product in the e-cigarette space due to their sleekness, ease of concealment, and versatility6. JUUL, a prominent pod-mod e-cigarette, fueled the youth e-cigarette epidemic due to youth-targeted advertisement, and until recently, was the most widely used e-cigarette brand among youth and young adults in the US7.

To understand the sociodemographic correlates and the predisposing factors associated with pod-based e-cigarette use among young college-aged adults in the United States, and to evaluate typical use patterns and addictive behaviors among this demographic group, we utilized an online survey tool administered to confirmed students aged 18–24 years in a University in Maryland, USA, who reported ever use of pod-based e-cigarettes. We also sought to understand the perceptions of harm associated with ENDS use juxtaposed with awareness about public health messages on tobacco use.

## METHODS

### Study participants and eligibility criteria

Participants were confirmed students from a large urban University in Maryland, USA, aged 18–24 years who reported ever use of pod-based e-cigarettes. Participants were recruited from September 2020 to March 2021 via regular announcements on the University’s media hub announcement page. Of the 604 individuals who indicated an interest in the study, 471 could not verify their student status and, thus, did not meet the eligibility criteria. The remaining 133 individuals received unique identifier numbers and a link to the survey, of whom 117 completed the survey. Among them, 5 individuals had inconsistent entries and were eliminated from the analyses. Therefore, 112 valid survey responses were analyzed.

### Study procedures

An online survey was designed on the University’s REDCap platform, a secure web application. The survey was designed to be easily understandable, with a Flesch-Kincaid grade level score of 7. Questions were developed based on the principles of the Integrated Behavioral Model13. When possible, questions were modeled after questions in the PhenX toolkit (an online catalog of scientifically validated measures related to a wide range of research domains, including tobacco regulatory research)1414. Others were modeled after prior published work (Supplementary file Document 1)15-19. In total, 75 questions were asked, grouped under the following domains: demographic information, general tobacco and other nicotine products use history, patterns of pod-mod use, perceptions of potential harms associated with vaping, and awareness of public health messages on vaping.

Approval for the study was obtained from the Johns Hopkins University’s Institutional Review Board, and all methods were performed in accordance with the Declaration of Helsinki.

To protect the identity of participants, their communication with the study team was via a designated member of the team with no access to the data. Participants’ student status was verified, and they were required to take an honor pledge that they met other eligibility criteria, following which they were given unique identification numbers (UIN). With these UINs, participants could access the survey where they were presented with informed consent for the study. After consenting to the study procedures, they could then take the survey. Upon completion, they received a $45 incentive and were asked for referrals of other students using pod-mod e-cigarettes who would be interested in taking the survey. Data from the study were stored and analyzed within a HIPAA compliant environment on the University’s SafeDesktop. ### Measures Demographic characteristics Participants were asked about their age, sex, race/ethnicity, and household income. Pod-mod use patterns An introduction about pod-mods and examples of brands were provided, together with a link to pictures. Participants were categorized based on their response to questions about past 30-day pod-mod use. Participants who reported past-30-day use of pod-mods were categorized as ‘current users’, and those who reported no use of pod-mods in the past 30-days were ‘non-current users’. Preferred flavors and brands were also assessed, and participants were asked about the number of pods they typically finished in a month. A brief introduction about other tobacco products was also provided, with a link to pictures. Participants were then asked about lifetime use and frequency of use (daily vs occasional use) of other nicotine products including cigarettes, cigars, cigarillos, pipes, hookah, smokeless tobacco (snus pouches, loose snus, moist snuff, dip, spit or chewing tobacco), and dissolvable tobacco. They were also asked about marijuana use. Predisposing factors and reasons for use To assess predisposing factors for initial and continued use, participants were asked questions about ages of initial and regular use. They were also asked about ownership of pod-mods and purchase patterns. To assess perceived social influence and acceptability of pod-mod use, the number of family/close friends who used pod-mods and their opinions about pod-mod use were asked. Questions were also asked to assess exposure to pod-mod marketing. To assess reasons for initiating pod-mod use, participants were asked: ‘why did you start using pod-mods’, several options were provided some of which included: ‘I was curious’, ‘Friends/Family use or gave me one to try’, ‘They are less harmful to me compared to smoking regular cigarettes’, ‘They helped me quit/reduce smoking’. Multiple answers were allowed. Participants were also asked about where they first tried pod-mods. Addictive behaviors, autonomy, and quit attempts To assess addictive behaviors, participants were asked questions including: ‘How soon after waking up do/did you take your first puff of a pod-mod’ and ‘Have you ever felt like you were addicted to using pod-mods’. Given that diminished autonomy is peculiar to all forms of drug or behavior dependence20, we adapted the hooked on nicotine checklist (HONC), a reliable and valid measure of diminished autonomy over tobacco, to assess participants’ addictive behaviors16,21. Participants were categorized into two groups: those with full autonomy (HONC score of 0) and those with reduced autonomy (HONC score ≥1). To assess characteristics associated with quit attempts, number of prior quit attempts, reasons for quitting, and symptoms experienced when they attempted to quit, were explored. Perceptions of potential harms Perceptions of potential harms were assessed with questions including: ‘What in your view are the main harms, if any, of pod-mod use’. Multiple answers were allowed and some of the options provided were: ‘there are no harms’ and ‘there has not been enough research done to understand all the possible harms’. Exposure to public health messages on vaping Participants were asked if they had seen any anti-smoking or anti-tobacco ads on TV or social media. Their opinions about the ads were assessed using a Likert scale from ‘strongly agree’ to ‘strongly disagree’. ### Statistical analysis Sociodemographic characteristics of participants were analyzed using descriptive analyses and data were presented using means/medians and proportions. Using descriptive analyses, current and non-current users were further characterized according to the domains listed earlier. The association between nicotine autonomy (HONC) and pod-mod brands, flavors, and the use of other nicotine products, was assessed using descriptive analyses and logistic regression models adjusted for age and sex. All analyses were conducted using Stata software version 15.1 (Stata Corp, College Station, TX), with statistical significance set using a two-sided p<0.05. ## RESULTS There were 112 eligible survey participants, of whom 59.8% were non-current users and 40.2% were current users. Participants had a mean age of 20.5 years (SD=1.2) and were predominantly female (56.3%), White (48.2%), non-Hispanic (83%), with household income above$100000 (61.6%). Compared to non-current users, a larger proportion of current users were male, White, and Hispanic. Other demographic characteristics were similar between both groups (Table 1).

##### Table 1

Demographic characteristics of survey participants on perception of health sociodemographic correlates of pod-based e-cigarette use and their interplay with other tobacco products, a cross-sectional study among college-aged adults, Maryland, USA, 2019

CharacteristicsTotal (N=112) n (%)Current users (N=45) n (%)Non-current users (N=67) n (%)
Age (years), mean ± SD20.5 ± 1.220.6 ± 1.220.4 ± 1.2
Sex
Female63 (56.3)21 (46.7)42 (62.7)
Male49 (43.8)24 (53.3)25 (37.3)
Race
Asian42 (37.5)14 (31.1)28 (41.8)
Black or African American8 (7.1)3 (6.7)5 (7.5)
White54 (48.2)24 (53.3)30 (44.8)
Multiracial4 (3.6)2 (4.4)2 (3.0)
Other4 (3.6)2 (4.4)2 (3.0)
Ethnicity
Hispanic19 (17.0)12 (26.7)7 (10.5)
Non-Hispanic93 (83.0)33 (73.3)60 (89.6)
Household income (US$) <350005 (4.5)2 (4.4)3 (4.5) 35000–500006 (5.4)1 (2.2)5 (7.5) 50000–7500011 (9.8)9 (20.0)2 (3.0) 75000–10000013 (11.6)5 (11.1)8 (11.9) >10000069 (61.6)26 (57.8)43 (64.2) Unsure8 (7.1)2 (4.4)6 (9.0) ### Pod-mod use characteristics Current users had higher average monthly pod consumption rates compared to non-current users when they were using pod-mods. Current users were also more likely to live with people who used pod-mods and have more friends who also used pod-mods. A larger proportion of current users also reported having tried multiple tobacco products: 82.2% had tried combustible cigarettes, 42.2% tried cigarillos, and 51.1% had tried hookah compared to 50.8%, 22.4%, and 29.9% of non-current users for each product, respectively. Only 2.2% of participants reported concurrent daily use of combustible cigarettes (Table 2). Overall, most participants reported that their close contacts had ambivalent (36.6%) or negative (48.2%) opinions about pod-mods. Their perception of the general public’s opinion of pod-mods followed a similar pattern (Table 2). ##### Table 2 Pod-mod use characteristics among survey participants, Maryland, USA, 2019 CharacteristicsTotal (N=112) n (%)Current users (N=45) n (%)Non-current users (N=67) n (%)p Age first tried pod-mods (years), mean ± SD17.8 ± 1.417.8 ± 1.317.8 ± 1.40.80 Age commenced regular use (years), mean ± SD18.5 ± 1.418.8 ± 1.318.3 ± 1.40.10 First pod flavor used0.05 Virginia tobacco1 (0.9)0 (0.0)1 (1.5) Mint41 (36.6)21 (46.7)20 (29.9) Mango28 (25)9 (20.0)19 (28.4) Crème5 (4.5)1 (2.2)4 (6.0) Cucumber3 (2.7)3 (6.7)0 (0.0) Classic tobacco2 (1.8)2 (4.4)0 (0.0) Menthol8 (7.1)3 (6.7)5 (7.5) Fruit17 (15.2)6 (13.3)11 (16.4) Other5 (4.5)0 (0.0)5 (7.5) None2 (1.8)0 (0.0)2 (3.0) Average monthly pod consumption (pods)0.01 <154 (48)15 (33.3)39 (58.2) 1–214 (12.5)6 (13.3)8 (11.9) 3–417 (15.2)6 (13.3)11 (16.2) 5–1214 (12.5)9 (20.0)5 (7.5) 13–197 (6.3)3 (6.7)4 (6.0) >206 (5.4)6 (13.3)0 (0.0) Living with people who use pod-mods37 (33.0)24 (53.3)13 (19.4)0.00 Number of friends who use pod-mods (among their five closest friends)0.01 016 (14.3)2 (4.4)14 (20.9) 134 (30.4)10 (22.2)24 (35.8) 229 (25.9)12 (26.7)17 (25.4) 319 (17.0)11 (24.4)8 (11.9) 49 (8.0)7 (15.6)2 (3.0) 55 (4.5)3 (6.7)2 (3.0) Opinion of close contacts about pod-mods0.59 Positive17 (15.2)6 (13.3)11 (16.4) Neither positive nor negative41 (36.6)19 (42.2)22 (32.8) Negative54 (48.2)20 (44.4)34 (50.8) Perception of general public’s opinion about using pod-mods0.19 Positive12 (10.7)2 (4.4)10 (14.9) Neither positive nor negative46 (41.1)21 (46.7)25 (37.3) Negative54 (48.2)22 (48.9)32 (47.8) Other tobacco product use Combustible cigarettes Ever use71 (63.4)37 (82.2)34 (50.8)0.00 Current occasional use18 (16.1)10 (22.2)8 (11.9)0.15 Current daily use1 (2.2)1 (2.2)0 (0.0)0.15 Traditional cigar/cigarillo/blunt Ever use (cigar)44 (39.3)21 (46.7)23 (34.3)0.19 Ever use (cigarillo)34 (30.4)19 (42.2)15 (22.4)0.03 Ever use (blunts)67 (59.8)32 (71.1)35 (52.2)0.05 Current occasional use (cigar/cigarillo/blunt)27 (24.1)11 (24.4)16 (23.9)0.95 Pipe Ever use20 (17.9)11 (24.4)9 (13.4)0.14 Current occasional use2 (1.8)1 (2.2)1 (1.5)0.69 Current daily use1 (0.9)0 (0.0)1 (1.5)0.69 Hookah Ever use43 (38.4)23 (51.1)20 (29.9)0.02 Current occasional use12 (10.7)4 (8.9)8 (11.9)0.61 Smokeless tobaccoa Ever use (snus pouches)6 (5.4)2 (4.4)4 (6.0)0.73 Ever use (loose snus/moist snuff)6 (5.4)3 (6.7)3 (4.5)0.61 Current daily use2 (1.8)0 (0.0)2 (3.0)0.24 a Snus pouches, loose snus, moist snuff, dip, spit, or chewing tobacco. ### Initiation of use The mean age of first experimentation with pod-mods was 17.8 years (SD=1.4), while the mean age of regular use was 18.5 years (SD=1.4). Figure 1 shows the distribution of participants’ responses to the question about their reasons for initiating pod-mod use; 67.9% reported initiation because ‘friends/family use or gave me one to try’, 62.2% reported being curious, and 25.9% tried them for the flavors. The majority reported first trying pod-mods at home or at a friend’s home (44.6%) or at a social gathering (party/nightclub/concert) (39.3%). ##### Figure 1 Reasons for initiation of pod-mod use (% participants) among college-aged adults in a crosssectional study on perception of health sociodemographic correlates of pod-based e-cigarette use and their interplay with other tobacco products, Maryland, USA, 2019 ### Characteristics of current users Among current users, 82.2% reported using JUUL most frequently in the past month, menthol was the most frequently used flavor (37.8%), and 62.2% owned their own pod-mods. A total of 26.7% had been advised by health professionals to quit in the past year, and 68.8% rarely or never read the health warnings on pod-mod packaging (Table 3). The majority (73.3%) reported buying pods in person, 45.5% of whom were aged <21 years. ##### Table 3 Characteristics of current users of pod-mods among survey participants, Maryland, USA, 2019 CharacteristicsCurrent users (N=45) n (%) Pod flavor used most frequently* Virginia tobacco2 (4.4) Mint9 (20) Mango4 (8.9) Menthol17 (37.8) Fruit7 (15.6) None4 (8.9) Own a pod-mod28 (62.2) Amount paid for pod-mods (US$)
<102 (4.4)
10–3021 (46.7)
31–406 (13.3)
Method of purchase of pods
In person33 (73.3)
From the internet2 (4.4)
Do not purchase my own10 (22.2)
Health professional advised to quit using pod-mods in last 12 months12 (26.7)
In the past 30 days, how often have you read the health warnings on pod-mod packages
Never20 (44.4)
Rarely11 (24.4)
Sometimes12 (26.7)
Often2 (4.4)
Very often0 (0.0)

* In the last 30 days.

### Addictive behaviors and quit attempts

Some of the addictive behaviors reported by participants include having strong cravings for pod-mods (45.5%), feeling of being addicted (36.6%), having strong urges to use them during quit attempts (41.1%), feeling nervous/anxious during quit attempts (32.1%), and difficulty concentrating during quit attempts (23.2%) (Table 4). A larger proportion of current users reported addictive behaviors compared to non-current users, and 82.2% of current users had plans of quitting pod-mod use in the next 6 months compared to 59.7% of non-current users. Overall, 67% of participants had a past serious quit attempt (Table 4).

##### Table 4

Addictive behaviors and quit attempts among survey participants, Maryland, USA, 2019

Total (N=112) n (%)Current users (N=45) n (%)Non-current users (N=67) n (%)p
Found it hard to concentrate because you could not use a pod-mod26 (23.2)14 (31.1)12 (17.9)0.05
Felt strong urge to use pod-mod when you could not use a pod-mod46 (41.1)28 (62.2)18 (26.9)0.00
Felt nervous, anxious or irritable because you could not use a pod-mod36 (32.1)20 (44.4)16 (23.9)0.03
Find/found it difficult to refrain from using in forbidden places, e.g. school, church25 (22.3)14 (31.1)11 (16.4)0.07
Feeling of being addicted to using pod-mods41 (36.6)26 (57.8)15 (22.4)0.00
Ever had strong cravings for pod-mods51 (45.5)32 (71.1)19 (28.4)0.00
Smoking more frequently during the first hours after waking than during the rest of the day18 (16.1)8 (17.8)10 (14.9)0.69
How soon after waking is/was first puff taken (minutes)
≤513 (11.6)6 (13.3)7 (10.5)0.11
6–3013 (11.6)9 (20.0)4 (6.0)
31–608 (8.0)4 (8.9)5 (7.5)
>6077 (68.8)26 (57.8)51 (76.1)
Quitting status
Considering quitting pod-mod use during the next 6 months77 (68.8)37 (82.2)40 (59.7)0.01
Past serious quit attempt75 (67.0)27 (60.0)48 (71.6)0.20

Among participants with quit attempts, majority tried quitting because they were concerned about potential health risks (72%), did not feel like using them any longer (41.3%), or because of the expensive cost (42.7%). The majority of participants who had tried quitting (89.3%) neither used nicotine replacement therapy nor prescription medications such as bupropion during quit attempts (Table 5).

##### Table 5

Characteristics associated with quit attempts among survey participants, Maryland, USA, 2019

CharacteristicsTotal (N=67) n (%)Current users (N=27) n (%)Non-current users (N=48) n (%)p
Longest length of time stopped using pod-mods because you were trying to quit0.00
<1 week5 (6.7)4 (14.8)1 (2.1)
1–3 weeks8 (10.7)5 (18.5)3 (6.3)
1–2 months11 (14.7)8 (29.6)3 (6.3)
3–11 months29 (38.7)20 (41.7)20 (41.7)
1–4 years19 (25.3)1 (3.7)18 (37.5)
Age during most recent quit attempt, mean ± SD19.6 ± 1.419.4 ± 1.520.0 ± 1.20.05
Reason for quitting (select all)
I was just experimenting26 (34.7)3 (11.1)23 (47.9)0.00
I did not feel like using them31 (41.3)12 (44.4)19 (39.6)0.68
I did not like the taste6 (8.0)1 (3.7)5 (10.4)0.30
It cost too much32 (42.7)15 (55.6)17 (35.4)0.09
It didn’t help me quit or cut back smoking1 (1.3)1 (3.7)0 (0.0)0.18
It didn’t help with my cravings1 (1.3)1 (3.7)0 (0.0)0.18
I was concerned about the health risks54 (72.0)18 (66.7)36 (75.0)0.44
The quality was poor3 (4.0)0 (0.0)3 (6.3)0.19
I did not like the side effects18 (24.0)7 (25.9)11 (22.9)0.77
I saw ads on potential dangers of vaping14 (18.7)1 (3.7)13 (27.1)0.01
During most recent quit attempt, did you use any of the following products to help you quit (select all)
Nicotine gum1 (1.3)1 (3.7)0 (0.0)0.18
Nicotine patch1 (1.3)1 (3.7)0 (0.0)0.18
Prescription pill2 (2.7)1 (3.7)1 (2.1)0.68
None of these67 (89.3)23 (85.2)44 (91.7)0.38

### Exposure to marketing/public health messages and perception of harm

Only a minority (17%) of participants reported seeing internet ads for pod-mods sometimes or most times, while 42.9% had never seen internet ads for them. However, 39.3% reported discussing pod-mods on their social networking accounts (Supplementary file Table 1). Although 74.1% of participants had seen anti-tobacco ads, only a minority (14.3%) had discussed the ad content with anyone. Approximately 35% thought the anti-tobacco ads were worth remembering, 39.3% agreed they were informative, and 27.7% thought they were convincing (Supplementary file Table 2).

Approximately 96% of participants were aware that pod-mods contain nicotine, 58% thought they were less harmful than cigarettes, and 47.3% thought they were less addictive than cigarettes. The most perceived harms associated with pod-mod use included: addiction (86.6%), respiratory problems (83.9%), harmful e-liquid constituents (75.9%), reinforcing of smoking habit (64.3%), and cancer (62.5%). Additionally, 74.1% of participants thought that not enough research had been done to understand all the harms associated with pod-mod use (Supplementary file Table 3).

### Characteristics of participants by nicotine autonomy status

Participants with reduced autonomy were more likely to be current users (61.3%), have JUUL as their most frequently used brand (62.9%), used menthol flavor most frequently (29%), and were more likely to have tried other tobacco products: cigarettes (77.4%), cigarillo (40.3%), blunt (70.9%) and hookah (51.6%) (Supplementary file Table 4).

In logistic regression analyses, after adjusting for age and sex, current users had 4.52 times (95% CI: 1.76–11.64) higher adjusted odds of having reduced autonomy compared to non-current users. Participants who used JUUL most frequently had 2.56 times (95% CI: 1.08–6.03) higher adjusted odds of having reduced autonomy compared to participants who had no preferred brand of pod-mods, and participants who used menthol flavor most frequently had 6.52 times (95% CI: 1.38–30.89) higher adjusted odds of having reduced autonomy compared to participants who had no preferred flavor of pods (Supplementary file Table 5).

## DISCUSSION

In this multi-faceted survey study of college-aged pod-mod users, we observed that current users were more likely to own their own pod-mods and use JUUL and menthol flavor pods most frequently compared to non-current users. They were also more likely to have tried multiple tobacco products, use more pods on average per month, live with people and have more friends who use pod mods, and report dependence/addictive behaviors compared to non-current users. A considerable proportion of current users aged <21 years reported buying their devices in-person. Overall, majority of participants initiated use due to curiosity and social influence, had well-informed perceptions of the potential harms associated with pod-mod use, and were considering quitting due to health risks. Additionally, the majority of the participants reported past year quit attempts without the use of NRT or prescription medications.

Reflecting its dominant share of the ENDS market space in 201926, JUUL was the most commonly used brand of e-cigarettes among participants in our study. This is consistent with other studies conducted among young adults in the population27, lending further credence to assertions that the explosion of ENDS use among youth between 2017 and 2019 was partly fueled by the brand28, whose influence is apparent regardless of education level. Similarly, menthol was the most frequently used flavor among participants in our study, also reflecting the ENDS market space, where following the federal ban of other flavors from the market, the menthol market share increased from 13% in 2019 to 46% in 202029.

Of note, JUUL and menthol flavor pod-mod use were associated with reduced autonomy among participants, suggesting a higher addiction potential for both products. This is not unexpected as JUUL pods contain nicotine concentrations as high as 40 mg/pod (equivalent to a pack of cigarettes)30, and menthol has been reported to increase nicotine dependence and hamper smoking cessation especially among youth, Black, and Hispanic individuals31.

In our study, pod-mod initiation was largely mediated by peer and family influence and curiosity, and continued use was associated with living with people or having friends who also used pod mods, regardless of perceived opinions of others about the product. Our findings among college students are consistent with other studies among youth, highlighting the importance of social influence in this demographic group27,32. Additionally, more participants reported discussing pod-mods on their social media platforms, while only few participants reported seeing internet ads of the products. This is particularly intriguing given the success of JUUL, a company that spent more resources on social media platforms compared to other tobacco companies33, buttressing that many of JUUL’s earlier marketing strategies unwittingly targeted younger individuals28. Also, although the Tobacco-21 law was passed in Maryland in 2019, restricting the sales of tobacco products, including ENDS, to individuals aged ≥21 years8, almost half of the current users who reported buying their pods in-person were aged <21 years. This is particularly concerning and necessitates stricter enforcement of the Tobacco-21 legislation.

Interestingly, the majority of participants reported having seen anti-tobacco ads, although very few engaged with them. Nonetheless, unlike other studies, a vast majority of the participants in our study were well-informed about the nicotine content and the potential harms associated with pod-mod use34, with most citing health concerns as their reason for attempting to quit. The majority of the participants in our study had tried to quit, however, considering the high nicotine content of many pod-mods and the ‘cold turkey’ approach to quitting adopted by many participants, it is not surprising that their quit attempts had been unsuccessful. Our findings suggest that quitting ENDS use may be challenging, and the use of nicotine replacement therapy and other prescription medications to this end should be explored. Furthermore, the use of multiple tobacco products observed among current users is in keeping with prior studies and may also be responsible for difficulty quitting15,16. Finally, only a handful of participants reported ever reading the warning labels on pod-mod packs. While the FDA’s guidelines for including health information on ENDS packaging is important35, a shift towards using graphical health warnings might be more likely to capture the attention of users.

Our findings provide important information on the factors associated with the use of pod-based e-cigarettes among college-aged adults. We provide additional insight into potential avenues for impactful youth education concerning ENDS use, for example, our data demonstrate that college pod-mod users are well-aware of the potential health consequences of these products, therefore, ongoing advertising campaigns on the dangers of pod-mods are unlikely to be effective – different approaches are needed to impact this important population. Additionally, our findings highlight the need for more robust evidence-based cessation support designed for college students trying to quit ENDS use for example, occupational health services on college campuses could be expanded to include ENDS cessation counseling. The need for tighter enforcement of established tobacco laws is also brought to the fore, and additional insight into the impact of current policies and the perception of public health messages will prove invaluable in building further strategies to reduce tobacco use in this population.

### Strengths and limitations

A major strength of our study was its careful inclusion of only university students who reported using pod-mods, with multiple safeguards to ensure the integrity of this population. Additionally, few participants were ‘dual users’ of pod-mods and combustible cigarettes, enabling us to focus on a group that were largely exclusive users of pod-mods. Our study however has several limitations. The sample size for our study was modest, and the selection of participants from a college limits the generalizability of our results to other young adults in the general population or from other regions or countries. The study’s modest sample size also precludes our determining variation by substantive demographic factors, such as race/ethnicity or sex. Also, the self-reported format of the survey might result in recall bias. The study was observational and cross-sectional, and hence we could not establish the temporality of the associations or establish causal relations.

## CONCLUSIONS

The use of pod-mods in our study of college-aged young adults was associated with experimentation with multiple tobacco products and addictive behaviors. Social influence played a major role in the uptake and continued use of pod-mods among users, and while many had attempted to quit due to the potential health effects associated with their use, many of the quit attempts were unsuccessful. Our results highlight the need for additional public health strategies and vaping cessation support targeted at college students in the US.