ENDS Users Research Articles

The role of puff volume in vaping emissions, inhalation risks, and metabolic perturbations: a pilot study

Secondhand vaping exposure is an emerging public health concern that remains understudied. In this study, saliva and exhaled emissions from ENDS users (secondhand) and non-ENDS users (baseline) were collected, firsthand emissions were generated using an automated ENDS aerosol generation system programmed to simulate puffing topography profiles collected from ENDS users. Particulate concentrations and sizes along with volatile organic compounds were characterized. We revealed puffing topography metrics as potential mediators of firsthand and secondhand particle and chemical exposures, as well as metabolic and respiratory health outcomes. Particle deposition modeling revealed that while secondhand emissions displayed smaller deposited mass, total and pulmonary particle deposition fractions were higher than firsthand deposition levels, possibly due to smaller secondhand emission particle diameters. Lastly, untargeted metabolomic profiling of salivary biomarkers of lung injury due to firsthand ENDS exposures revealed potential early indicators of respiratory distress that may also be relevant in bystanders exposed to secondhand vaping scenarios. By leveraging system toxicology, we identified 10 metabolites, including leukotriene D4, that could potentially serve as biomarkers for ENDS use, exposure estimation, and the prediction of vaping-related disease. This study highlights characterization of vaping behavior is an important exposure component in advancing our understanding of potential health effects in ENDS users and bystanders.

Acute analgesic effect of nicotine vaping using three experimental pain induction tasks: a randomized, placebo-controlled laboratory study.

Pain and nicotine use are co-occurring conditions with a significant impact on health. Experimental evidence supports an acute analgesic effect of nicotine which may reinforce nicotine use among those with chronic pain. Evidence for nicotine analgesia have primarily been gathered in combustible cigarette users and have not been extended to electronic nicotine delivery systems (ENDS or vaping). Furthermore, the mechanisms of nicotine analgesia in humans are not well understood. Assess the effect of acute vaped nicotine on subjective and behavioral indices of pain sensitivity using three tasks designed to probe distinct mechanisms of analgesia. This study recruited ENDS users (N = 86) to undergo a paced vaping protocol followed by pain tasks in counterbalanced order. Across four sessions, participants vaped e-liquid containing nicotine or placebo, and flavor or no-flavor in a 2 × 2 within-subject design. Assessments included cold pressor, submaximal effort tourniquet to induce ischemic pain, and temporal summation of heat pain, an index of central sensitization. Compared to placebo, nicotine increased cold pressor pain tolerance (ηp2 = 0.031), ischemic pain threshold (ηp2 = 0.073) and tolerance (ηp2 = 0.056) but had no effect on temporal summation of pain. Flavor did not affect pain sensitivity. Females reported greater ischemic pain sensitivity (ηp2 = 0.027) and greater reductions in craving (ηp2 = 0.086). Consistent with research from tobacco smoking, analgesia may be reinforcing and contribute to nicotine dependence among ENDS users. More research on sex differences is warranted.

Associations between ENDS and cigarette use, and compromised immunity in US adults: Findings from the 2021–2022 NHIS

Background Tobacco use presents increased risks for individuals with weakened immune systems (WIS). We investigated the association between cigarette and electronic nicotine delivery systems (ENDS or e-cigarettes) use and WIS in US adults using data from the 2021–2022 National Health Interview Survey. Methods Data from 57,133 adults were analyzed, focusing on WIS prevalence due to health conditions, prescriptions, or both. Cigarette and ENDS use were categorized as never, former, or current. Weighted multivariable regression models adjusted for demographics and other health conditions to assess associations between tobacco use and WIS. Results Among US adults, 4.3% had prescription-related WIS, 4.6% had health condition-related WIS, and 7% had WIS due to either reason. Adjusted results from multivariable regression models indicated that adults with WIS due to health conditions were more likely to be current (AOR = 1.21, 95%CI: 1.05–1.40) and former (AOR = 1.25, 95%CI: 1.11–1.39) cigarette smokers compared to counterparts without WIS. Adults with WIS due to prescriptions were more likely to be former cigarette smokers (AOR = 1.19, 95%CI: 1.06–1.34). Those with WIS for any reason were more likely to be current (AOR = 1.19, 95%CI: 1.05–1.35) and former (AOR = 1.24, 95%CI: 1.13–1.36) cigarette smokers. Adults with WIS due to health conditions (AOR = 1.23, 95%CI: 1.06–1.41) or any reasons (AOR = 1.19, 95%CI:1.05–1.34) were more likely to be former ENDS users compared to those without WIS. Conclusions In this nationally representative study, we found a notable link between cigarette and ENDS use with WIS, particularly among those with health condition-related or prescription-related WIS, underscoring the importance of addressing tobacco use in this vulnerable population.

Nicotine dependence among young adults: Comparing exclusive ENDS users to exclusive cigarette smokers

PurposeNo studies of young adults have compared symptoms of nicotine dependence among exclusive past 30-day (P30D) ENDS users versus exclusive P30D cigarette smokers. MethodsParticipants at Wave 14 (Fall 2021) of The Texas Adolescent and Tobacco Marketing Surveillance System (TATAMS) (n = 2,341; mean age = 20.95 years old) who reported P30D exclusive ENDS use (n = 212) and P30D exclusive cigarette smoking (n = 46). Symptoms of nicotine dependence were measured with the Hooked On Nicotine Checklist (the 10-item HONC scale). An independent samples t-test compared average HONC scores between groups, and a Pearson (or Fisher’s Exact) Chi-Square (X2) test compared the prevalence of symptom(s) between groups. ResultsThe average HONC score was significantly higher for exclusive P30D ENDS users than exclusive P30D cigarette smokers (3.51 vs. 1.91, p ≤ 0.001). Compared to exclusive P30D cigarette smokers, a significantly higher proportion of exclusive P30D ENDS users reported having felt addicted (45.28% vs. 15.22%, p ≤ 0.001), having strong cravings (50.00% vs. 28.26%, p = 0.007), difficulty not using in prohibited places (i.e., school or work) (24.06% vs. 4.35%, p = 0.002), difficulty concentrating (21.23% vs. 6.52%, p = 0.021), and feeling nervous, restless, or anxious (28.77% vs. 10.87%, p = 0.012). ConclusionsSymptoms of nicotine dependence were elevated among young adults who were exclusive P30D users of ENDS relative to exclusive P30D cigarette smokers.

Device and liquid characteristics used with sweet, menthol/mint, and tobacco ENDS liquid flavors: The population-based VAPER study

IntroductionElectronic nicotine delivery system (ENDS) device and liquid characteristics (e.g., wattage, nicotine concentration) are diverse and important in determining product appeal, aerosol volume/nicotine levels, and toxicity. Little is known about how device and liquid characteristics vary by flavor; we address this gap to identify potential regulatory implications. MethodsData are from a longitudinal cohort study (Waves 2 and 3; December 2020-December 2021) of adult (≥21 years) U.S. ENDS users (≥5 days of use/week). Participants (n = 1809) reported on and submitted photos of their most used device and liquid. Participants were categorized into flavor groups of high prevalence in our sample and in prior literature: sweet, menthol/mint, or tobacco. Participants using liquids without nicotine or flavors other than sweet, menthol/mint, or tobacco were excluded (n = 320). Data were analyzed cross-sectionally. Chi-square and linear regression (n = 1489) were used to examine device and liquid characteristics by flavor. ResultsSweet flavors were most common (n = 1135; 76.2%), followed by menthol/mint (n = 214, 14.4%) and tobacco (n = 140, 9.4%). Sweet flavors were less common among participants using reusable devices with disposable pods/cartridges (nicotine salt) than those using other device-liquid groupings (5.2% vs 86.5–93.9%; p < 0.001). Sweet flavors were less common among those using ENDS for non-flavor reasons vs the flavor (73.5% vs 90.4%; p < 0.001). Sweet flavors correlated with lower nicotine concentrations, higher wattages, and lower ages of ENDS first use (p < 0.001). ConclusionsRegulatory agencies must consider how regulations on device and liquid characteristics may affect ENDS users’ behaviors (e.g., limiting availability of sweet flavors may encourage use of non-sweet flavors and lower wattages).

Supplemental Material for Effects of Short-Term Nicotine Deprivation on Delay Discounting Among Young, Experienced, Exclusive ENDS Users: An Initial Study

Supplemental Material for Effects of Short-Term Nicotine Deprivation on Delay Discounting Among Young, Experienced, Exclusive ENDS Users: An Initial Study

Association of preferred flavorings and device type with box or pack purchase behavior of electronic nicotine delivery systems in the United States.

This study examined the associations of preferred flavorings and device type of ENDS with box or pack purchase behavior. We analyzed current adult ENDS users in the United States who reported purchase of their own ENDS. Logistic regression revealed an increased likelihood of box/pack purchase behavior among users of menthol or mint-flavored ENDS, disposable, pod-based devices, and those who purchase ENDS from the Internet. A moderation analysis showed that the magnitude of the association between menthol or mint-flavored ENDS use and box/pack purchase was stronger among disposable and pod-based device users compared to tank or mods (customizable devices) users. In a subsequent stratified analysis menthol or mint flavor users were more likely than non-flavor users to engage in box/pack purchase among disposable and pod-based device users, but not among tank or mods users. Regulating flavors and maximum unit sale quantities of ENDS by device could thwart ENDS box/pack purchase behavior.

Association of E-Cigarettes With Erectile Dysfunction: The Population Assessment of Tobacco and Health Study

Smoking is independently associated with erectile dysfunction and cardiovascular disease. Given existing similarities in the constituents of e-cigarettes or ENDS and cigarettes, this study examines the association between ENDS use and erectile dysfunction. Data from Wave 4 (2016-2018) of the Population Assessment of Tobacco and Health study were analyzed in 2020. Male participants aged ≥20 years who responded to the erectile dysfunction question were included. Multivariable logistic regression models examined the association of ENDS use with erectile dysfunction within the full sample and in a restricted sample (adults aged 20-65 years with no previous cardiovascular disease diagnosis) while adjusting for multiple risk factors. The proportion of erectile dysfunction varied from 20.7% (full sample) to 10.2% (restricted sample). The prevalence of current ENDS use within the full and restricted samples was 4.8% and 5.6%, respectively, with 2.1% and 2.5%, respectively, reporting daily use. Current daily ENDS users were more likely to report erectile dysfunction than never users in both the full (AOR=2.24, 95% CI=1.50, 3.34) and restricted (AOR=2.41, 95% CI=1.55, 3.74) samples. In the full sample, cardiovascular disease history (versus not present) and age ≥65 years (versus age 20-24 years) were associated with erectile dysfunction (AOR=1.39, 95% CI=1.10, 1.77; AOR= 17.4, 95% CI=12.15, 24.91), whereas physical activity was associated with lower odds of erectile dysfunction in both samples (AOR range=0.44-0.58). The use of ENDS seems to be associated with erectile dysfunction independent of age, cardiovascular disease, and other risk factors. While ENDS remain under evaluation for harm reduction and smoking-cessation potential, ENDS users should be informed about the possible association between ENDS use and erectile dysfunction.

Abstract 10690: Prevalence of Electronic Cigarette Use and Its Determinants in Us Persons of Hispanic Heritage: The Hispanic Community Health Study / Study of Latinos (HCHS/SOL)

Introduction: Popularity and use of electronic nicotine delivery systems (ENDS or e-cigarettes), have increased tremendously in the United States (US). Yet, data in a representative sample of US Hispanics/Latinos is limited. We determined the prevalence and correlates of ENDS use from the national Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Methods: Cross-sectional data collected between the years 2015–2017 were analyzed to assess ENDS use (ever (current: use ≤ past 30 days; former: use &gt; past 30 days) and never) among 11,623 adults aged 23+ years. Weighted prevalence estimates were reported and age-adjusted logistic regression models were used to examine associations between sociodemographic, lifestyle/behavioral, and clinical exposures with ENDS use (vs. nonsmokers and cigarette-only smokers, separately). Results: Mean age 47 years ± 0.3 and 52% women. The weighted prevalence of current and former ENDS use was 2.0% and 10.4%, respectively. Over 67% of current ENDS users reported dual-cigarette use. Current ENDS use prevalence estimates ranged from 1.1% in Hispanics/Latinos of South American background to 2.1% in Hispanics/Latinos of Mexican and Puerto Rican background. In logistic regression models, compared with nonsmokers, increased odds of current ENDS use was associated with males (OR=4.90, p&lt;0.001), higher education (OR=2.03, p&lt;0.05), English language preference (OR=7.59, p&lt;0.001), Puerto Rican background (OR=2.09, p&lt;0.05), a high level of physical activity (OR=4.02, p&lt;0.001), and history of alcohol use (OR=15.93, p&lt;0.001). Older age (≥45 years) (OR=0.30, p&lt;0.001), foreign-born participants (OR=0.12, p&lt;0.001), and those with obesity (OR=0.60, p&lt;0.05) and type 2 diabetes (OR=0.46, p&lt;0.001) had lower odds of current ENDS use. These trends were generally similar when cigarette-only smokers were the reference group. Having ever used ENDS was associated with prevalent coronary artery disease. Conclusions: Our study suggest that Hispanic/Latino individuals who are young adults, male, US-born, or have high acculturation are more likely to report current ENDS use.

Cross-Sectional Associations of Multiple Tobacco Product Use with Depressive and Anxiety Symptoms among Young Adult E-Cigarette Users

Background Tobacco users with mental health conditions are a vulnerable population in tobacco research, yet few studies have evaluated the association of depressive and anxiety symptoms with multiple tobacco product (MTP) use among young adult electronic cigarette (ENDS) users. Methods Cross-sectional survey data on U.S. young adult past 30-day ENDS users (N = 2348) were collected via Amazon MTurk from May-July 2019. Binary logistic regressions evaluated the association of tobacco use pattern (exclusive ENDS use, ENDS + one other tobacco product [OTP; dual use], ENDS + two or more OTPs [poly-use]) with depressive (PHQ-9) and anxiety (GAD-7) symptoms. Among MTP users (n = 1736), we evaluated the association of ENDS use relative to OTP use and same-day MTP use with depressive and anxiety symptoms. Results The sample included 26% exclusive ENDS, 27% dual, and 47% poly-users. We observed a gradient-relationship for depressive and anxiety symptoms: poly-users had greater odds of depressive and anxiety symptoms compared to dual users (aOR = 1.86 [95%CI:1.50–2.30] and aOR = 1.61 [95%CI:1.30–2.01], respectively), and dual users had greater odds of depressive and anxiety symptoms compared to exclusive ENDS users (aOR = 1.42 [95%CI:1.11–1.81] and aOR = 1.56 [95%CI:1.20–2.02], respectively). MTP users who used ENDS more often than OTPs (vs. less often than OTPs) had greater odds of depressive (aOR = 1.38 [95%CI:1.06–1.80]) and anxiety (aOR = 1.37 [95%CI:1.04–1.79]) symptoms. Conclusions The majority of young adult past 30-day ENDS users in this sample reported OTP use. Future research on MTP use should distinguish between dual and poly-use. Tobacco prevention efforts for young adults with mental health symptoms are needed.

Effect of flavour manipulation on ENDS (JUUL) users’ experiences, puffing behaviour and nicotine exposure among US college students

SignificanceElectronic nicotine delivery system (ENDS) use has continued to increase exponentially among young people in the USA, with unique flavours being one of the most cited reasons for use. Yet,...

Impact of Campus Tobacco-Free Policy on Tobacco and Electronic Nicotine Delivery Systems Initiation and Cessation among Students, Faculty, and Staff

Objective: This study examines the effects of having a tobacco free policy in three University of Alaska campuses two years postimplementation among students, faculty, and staff. It also identifies factors associated with tobacco cessation and ENDS use. Methods: Self-administered online survey was conducted in spring 2017 and 2018. Results: Most of the current tobacco users began using tobacco prior to policy implementation, while most current ENDS users in 2018 started using ENDS when the policy had been in place. Students and those who are younger are more likely to quit tobacco during policy implementation; and males, students, and those who are younger and current tobacco users are more likely to use ENDS. Conclusions: Study findings suggest that campus tobacco-free policy can promote tobacco cessation and help prevent tobacco initiation. However, such a policy does not necessarily affect ENDS use. Specific groups need additional interventions to assist in tobacco and ENDS cessation.

Adverse Experience Reports of Seizures in Youth and Young Adult Electronic Nicotine Delivery Systems Users

PurposeElectronic nicotine delivery systems (ENDS) use poses significant and avoidable health risks to young people. Until recently, seizures were most often associated with cases of liquid nicotine ingestion. MethodsWe examined 122 voluntary reports of seizures (n = 114) and neurological symptoms (syncope, n = 7; and tremor, n = 1) in 123 ENDS users (one report contained information on two users) received by the Food and Drug Administration between December 1, 2010, and June 30, 2019. ResultsThe median age (interquartile range) of users was 20 years (17–27); 67% of reports were in youth and young adults aged 14–24 years. Fifty-one (41%) reported other underlying medical conditions, including previous history of anxiety (n = 11), attention deficit hyperactivity disorder (n = 7), seizure (n = 6), and depression (n = 5). Of the 79 reports with available information, 67 (85%) reported seizure occurred within 24 hours of last use; 49 (62%) reported seizure within 30 minutes. The potential impact of concomitant use of marijuana or cannabidiol oil could not be evaluated from the eight reports that mentioned concomitant use. ConclusionsFindings suggest an association between ENDS use and seizures. Additional information will help to clarify the relationship between ENDS use and seizures and to understand how product attributes such as nicotine content, formulation, quantity, and other ingredients or contaminants may contribute to seizures. It is important that health care providers ask about ENDS use when evaluating neurological symptoms and that users, parents, school personnel, and health care providers report adverse experiences involving tobacco products to Food and Drug Administration via the Safety Reporting Portal (www.safetyreporting.hhs.gov).

Assessing the Effect of Flavor on ENDS Users' Experiences and Exposures

Assessing the Effect of Flavor on ENDS Users' Experiences and Exposures

Vaping, Smoking, and the Physical Fitness of Active Young Men

Adverse effects of cigarette smoking on physical performance are well studied. Because of the recent rise in popularity of vaping, it is important to evaluate its effect on fitness both independently and in conjunction with traditional cigarette use. This was a secondary analysis performed in 2018 on data collected from U.S. Army Soldiers during 2016. All metrics were self-reported via an electronic questionnaire. Personal characteristics of current ENDS users, smokers, and dual users were compared with a reference group that reported no history of use. Adjusting for age and physical training habits, an ANCOVA was used to compare Army physical fitness test results. A Fisher's exact test determined specific mean differences between groups. This study population consisted of 2,854 men aged 24.6 years on average. Differences in physical training and fitness were shown between the groups. Never users averaged the most total physical training, followed by ENDS users, smokers, and then dual users. Compared with never users on the fitness tests, ENDS users had an adjusted mean difference of +27 seconds on the 2-mile run, -4.56 push-ups, and -2.01 sit-ups; smokers averaged +8 seconds, -2.15 push-ups, and -1.44 sit-ups; and dual users averaged +32 seconds, -5.17 push-ups, and -3.88 sit-ups. Dual users had significantly (p<0.05) lower scores than current smokers and never users on all 3 fitness events. This study suggests that individuals who use e-cigarettes and tobacco cigarettes average a lower level of fitness than individuals who abstain.

An Analysis of Associations Between Electronic Nicotine Delivery System Users.

Electronic nicotine-delivery systems have been increasing in prevalence among young adults. Although these devices are marketed to aid in quit smoking, young adults who do not smoke traditional cigarettes are using these devices. This study explored associations between individuals' quit type (ie, no plans to quit, plans to quit, or quit > 6 months ago) and perceived health status, perception of harm compared to cigarettes, perception of secondhand vapor harm, and reasons for first use. We utilized a cross-sectional study design using a 33-item electronic survey questionnaire. The total sample size was 2,792. Out of these the ENDS users were 1,217. The survey was distributed to university students in 5 areas in 3 countries: the United States (ie, Florida, Alabama, and Illinois), Germany (ie, Hamburg) and South Africa (ie, Potchefstroom). Quantitative data analysis indicated that, regardless of quit status, there was a general lack of knowledge regarding secondhand vapor effects. Additionally, young adults are utilizing these products primarily due to peer influence and stress relief. Harm perception may factor into quit attempts using electronic nicotine-delivery systems. Education provided by respiratory therapists (and to respiratory therapy students) would be valuable as they inform patients and communities of the scholarly literature on vaping devices.

Flavored ENDS Use among Adults Who Have Used Cigarettes and ENDS, 2016-2017.

In this study, we assessed differences in type, number, and perceptions of ENDS flavors used at initiation and currently among 4 smoking and ENDS use profiles of US adults with a history of smoking and ENDS use. Our nationally representative survey sample included 1814 participants. We estimated Rao-Scott χ2 and adjusted odds ratios. Use profiles included: (1) Dual Users (current smokers/current ENDS users), (2) ENDS Rejecters (current smokers/former ENDS users), (3) Switchers (former smokers/current ENDS users), and (4) Quitters (former smokers/former ENDS users). Multiple flavor use at initiation was associated with higher odds of being a Dual User or Switcher. Those who used mint/wintergreen/menthol flavored ENDS at initiation had lower odds of being an ENDS Rejecter (vs Dual User). Current use of tobacco/unflavored or menthol/mint/wintergreen flavor was associated with higher odds of being a Dual User (vs Switcher). Switchers were more likely to perceive flavors as safe in ENDS and rate flavors as important to their ENDS use. Multiple flavor use at initiation, perceiving flavors as safe, and use of specific flavors (mint/wintergreen/menthol) at initiation may discourage rejecting ENDS. However, current use of traditional cigarette flavors (ie, tobacco, menthol) may promote sustained smoking.

Who does use ENDS in Russia? Results from Russian tobacco control policy evaluation survey EPOCHA-RF

Abstract Background Electronic Nicotine Delivery Systems (ENDS) become popular in Russia. Still little is known about use of these products. Aim To assess patterns of active and passive exposure to ENDS in Russian population. Methods Data from Russian tobacco control policy evaluation survey (2017-2018) are analysed, conducted on the basis of multistage territorial random sample of 11625 respondents: 6569 smokers, 2377 former smokers and 2679 never smokers 18years and older in 10 Russian Federal subjects. Results 38.8% of the respondents were familiar with ENDS, with the highest proportion in the youngest age group (18-24): 53.8%(p&amp;lt;.0001). 9.3%had tried ENDS, among 18-24 years old - those were 23.5%(p&amp;lt;.0001). The amount was significantly higher among recent quitters (in last 3years)-17.2%, and current smokers-13% compared with former (quitters for more than 3years) and never smokers. Of those 26.4% used ENDS regularly-with highest proportion among 18-24years old (29.1%), and current smokers (27.1%). This comprises 2.5% of respondents as regular ENDS users, and 6.8%-among the youngest group. Half of the smokers had tried to quit by means of ENDS, of those 69% failed to quit smoking, and 79% could neither give up smoking nor ENDS. However, only 18% ENDS users agreed that e-cigarettes cause addiction, and 37% even denied the fact. Those were mostly the youngest respondents (45%). Vaping was not allowed at homes of 67.4%respondents, at workplaces-of 65.6%. 14% of respondents had witnessed vaping at workplaces, 55.8% in public places, 20.3% cafes, restaurants and bars. 51.4% had been exposed to secondhand aerosols of ENDS and 73.2%-among 18-24years olds. 37%found exposure to the aerosols annoying, with significant differences between never/former smokers (58% and 50.3%) and recent quitters and current smokers (39.3% and 29.2%). Conclusions Young people are mostly exposed to ENDS in Russia. Strong legislation should be considered to regulate ENDS and protect people from their exposure. Key messages Electronic cigarettes are mostly prevalent among the youngest age groups, current smokers and recent quitters in Russia. ENDS do not help smokers to quit: vast majority of smokers who used ENDS for this purpose failed to give up both smoking and electronic cigarettes.

Longitudinal e-Cigarette and Cigarette Use Among US Youth in the PATH Study (2013-2015).

Evidence is accumulating that youth who try Electronic Nicotine Delivery Systems (ENDS, e-cigarettes) may go on to try cigarettes. This analysis examines the bidirectional patterns of ENDS and cigarette use among US youth over one year and uses propensity score matching (PSM) to examine frequency of ENDS use on changes in cigarette smoking. Our analysis included 11 996 participants who had two waves of available data (Wave 1 [W1] 2013-2014; Wave 2 [W2] 2014-2015) drawn from the longitudinal Population Assessment of Tobacco and Health Study. Cross-sectional weighted prevalence estimates are reported for cigarettes and ENDS. We used PSM to estimate the likelihood of ENDS use at W1 and to draw matched analytic samples, then used regression (logistic or linear) models to examine the effect of W1 ENDS use on W2 cigarette smoking. All statistical tests were two-sided. In weighted analyses, 69.3% of W1 past-30-day cigarette smokers exhibited past-30-day smoking at W2; 42.2% of W1 past-30-day ENDS users were using ENDS at W2. W1 ever use of either product was similarly associated with W2 new use of the other product. Unweighted PSM models indicated W1 cigarette-naïve ENDS use was associated with W2 ever-cigarette smoking (n = 676; adjusted odds ratio = 3.21, 95% confidence interval [CI] = 1.95 to 5.45, P < .001); W1 ever-ENDS use did not affect change in cigarette frequency at W2 (n = 1020, beta = 0.31, 95% CI = -0.76 to 1.39, P = .57); 1-5 days ENDS use compared with ever, no past-30-day ENDS use was associated with a statistically significant decrease of W2 smoking days (n = 256, beta = -2.64, 95% CI = -4.96 to -0.32; P = .03); and W1 6+ day ENDS users did not show a decrease in frequency of cigarette smoking. Ever-ENDS use predicts future cigarette smoking, and frequency of ENDS use has a differential impact on subsequent cigarette smoking uptake or reduction. These results suggest that both cigarettes and ENDS should be targeted in early tobacco prevention efforts with youth.

Co-use of Electronic Nicotine Delivery Systems and Combustible Cigarettes, and Their Association with Internalizing Pathology and Vulnerabilities

Nicotine use and psychological distress exert negative bidirectional effects on one another, and are impacted by shared vulnerabilities. Little work has examined the extent to which these relations differ between adult electronic nicotine delivery system (ENDs) users with varied combustible cigarette use histories. The current study examined differences in internalizing symptoms and vulnerabilities between adult dual and single ENDs users with and without a history of combustible cigarette use. Single ENDs users without combustible use histories reported significantly greater stress and anxiety symptoms than single ENDs users with combustible use histories. Single ENDs users without combustible use histories reported greater anxiety and difficulty regulating their emotions than dual-users. Dual-and single users with prior combustible use histories did not differ in internalizing pathology or vulnerability presentations. This suggests that pathology and vulnerability presentation among nicotine users are influenced by both current and past nicotine use history.