Vaping and Lung Inflammation and Injury.

The use of electronic (e)-cigarettes was initially considered a beneficial solution to conventional cigarette smoking cessation. However, paradoxically, e-cigarette use is rapidly growing among nonsmokers, including youth and young adults. In 2019, this rapid growth resulted in an epidemic of hospitalizations and deaths of e-cigarette users (vapers) due to acute lung injury; this novel disease was termed e-cigarette or vaping use-associated lung injury (EVALI). Pathophysiologic mechanisms of EVALI likely involve cytotoxicity and neutrophilic inflammation caused by inhaled chemicals, but further details remain unknown. The undiscovered mechanisms of EVALI are a barrier to identifying biomarkers and developing therapeutics. Furthermore, adverse effects of e-cigarette use have been linked to chronic lung diseases and systemic effects on multiple organs. In this comprehensive review, we discuss the diverse spectrum of vaping exposures, epidemiological and clinical reports, and experimental findings to provide a better understanding of EVALI and the adverse health effects of chronic e-cigarette exposure.

Intrauterine exposure to nicotine through maternal vaping disrupts embryonic lung and skeletal development via the Kcnj2 potassium channel.

Smoking cigarettes during pregnancy is associated with adverse effects on infants including low birth weight, defective lung development, and skeletal abnormalities. Pregnant women are increasingly turning to vaping [use of electronic (e)-cigarettes] as a perceived safer alternative to cigarettes. However, nicotine disrupts fetal development, suggesting that like cigarette smoking, nicotine vaping may be detrimental to the fetus. To test the impact of maternal vaping on fetal lung and skeletal development in mice, pregnant dams were exposed to e-cigarette vapor throughout gestation. At embryonic day (E)18.5, vape exposed litter sizes were reduced, and some embryos exhibited growth restriction compared to air exposed controls. Fetal lungs were collected for histology and whole transcriptome sequencing. Maternally nicotine vaped embryos exhibited histological and transcriptional changes consistent with impaired distal lung development. Embryonic lung gene expression changes mimicked transcriptional changes observed in adult mouse lungs exposed to cigarette smoke, suggesting that the developmental defects may be due to direct nicotine exposure. Fetal skeletons were analyzed for craniofacial and long bone lengths. Nicotine directly binds and inhibits the Kcnj2 potassium channel which is important for bone development. The length of the maxilla, palatal shelves, humerus, and femur were reduced in vaped embryos, which was further exacerbated by loss of one copy of the Kcnj2 gene. Nicotine vapor exposed Kcnj2KO/+ embryos also had significantly lower birth weights than unexposed animals of either genotype. Kcnj2 mutants had severely defective lungs with and without vape exposure, suggesting that potassium channels may be broadly involved in mediating the detrimental developmental effects of nicotine vaping. These data indicate that intrauterine nicotine exposure disrupts fetal lung and skeletal development likely through inhibition of Kcnj2.

Chronic low-level JUUL aerosol exposure causes pulmonary immunologic, transcriptomic, and proteomic changes.

E-cigarettes currently divide public opinion, with some considering them a useful tool for smoking cessation and while others are concerned with potentially adverse health consequences. However, it may take decades to fully understand the effects of e-cigarette use in humans given their relative newness on the market. This highlights the need for comprehensive preclinical studies investigating the effects of e-cigarette exposure on health outcomes. Here, we investigated the impact of chronic, low-level JUUL aerosol exposure on multiple lung outcomes. JUUL is a brand of e-cigarettes popular with youth and young adults. To replicate human exposures, 8- to 12-week-old male and female C57BL/6J mice were exposed to commercially available JUUL products (containing 59 mg/ml nicotine). Mice were exposed to room air, PG/VG, or JUUL daily for 4 weeks. After the exposure period, inflammatory markers were assessed via qRT-PCR, multiplex cytokine assays, and differential cell count. Proteomic and transcriptomic analyses were also performed on samples isolated from the lavage of the lungs; this included unbiased analysis of proteins contained within extracellular vesicles (EVs). Mice exposed to JUUL aerosols for 4 weeks had significantly increased neutrophil and lymphocyte populations in the BAL and some changes in cytokine mRNA expression. However, BAL cytokines did not change. Proteomic and transcriptomic analysis revealed significant changes in numerous biological pathways including neutrophil degranulation, PPAR signaling, and xenobiotic metabolism. Thus, e-cigarettes are not inert and can cause significant cellular and molecular changes in the lungs.

Statistical methods for predicting e-cigarette use events based on beat-to-beat interval (BBI) data collected from wearable devices.

The prevalence of e-cigarette use among young adults in the USA is high (14%). Although the majority of users plan to quit vaping, the motivation to make a quit attempt is low and available support during a quit attempt is limited. Using wearable sensors to collect physiological data (eg, heart rate) holds promise for capturing the right timing to deliver intervention messages. This study aims to fill the current knowledge gap by proposing statistical methods to (1) de-noise beat-to-beat interval (BBI) data from smartwatches worn by 12 young adult regular e-cigarette users for 7 days; and (2) summarize the de-noised data by event and control segments. We also conducted a comprehensive review of conventional methods for summarizing heart rate variability (HRV) and compared their performance with the proposed method. The results show that the proposed singular spectrum analysis (SSA) can effectively de-noise the highly variable BBI data, as well as quantify the proportion of total variation extracted. Compared to existing HRV methods, the proposed second order polynomial model yields the highest area under the curve (AUC) value of 0.76 and offers better interpretability. The findings also indicate that the average heart rate before vaping is higher and there is an increasing trend in the heart rate before the vaping event. Importantly, the development of increasing heart rate observed in this study implies that there may be time to intervene as this physiological signal emerges. This finding, if replicated in a larger scale study, may inform optimal timings for delivering messages in future intervention.

Key issues surrounding the health impacts of electronic nicotine delivery systems (ENDS) and other sources of nicotine.

Answer questions and earn CME/CNE Over the last decade, the use of electronic nicotine delivery systems (ENDS), including the electronic cigarette or e-cigarette, has grown rapidly. More youth now use ENDS than any tobacco product. This extensive research review shows that there are scientifically sound, sometimes competing arguments about ENDS that are not immediately and/or completely resolvable. However, the preponderance of the scientific evidence to date suggests that current-generation ENDS products are demonstrably less harmful than combustible tobacco products such as conventional cigarettes in several key ways, including by generating far lower levels of carcinogens and other toxic compounds than combustible products or those that contain tobacco. To place ENDS in context, the authors begin by reviewing the trends in use of major nicotine-containing products. Because nicotine is the common core-and highly addictive-constituent across all tobacco products, its toxicology is examined. With its long history as the only nicotine product widely accepted as being relatively safe, nicotine-replacement therapy (NRT) is also examined. A section is also included that examines snus, the most debated potential harm-reduction product before ENDS. Between discussions of NRT and snus, ENDS are extensively examined: what they are, knowledge about their level of "harm," their relationship to smoking cessation, the so-called gateway effect, and dual use/poly-use. CA Cancer J Clin 2017;67:449-471. © 2017 American Cancer Society.

Time to first report of signs of nicotine dependence among youth who use e-cigarettes and cigarettes in the United States: A nationally representative cohort study, findings from the Population Assessment of Tobacco and Health, 2013-2019.

OBJECTIVE: To determine the time to first report of signs of nicotine dependence among youth exclusive e-cigarette users and compare this time to that for exclusive cigarette users. METHODS: Secondary analysis of data (Waves 1-5; 2013-2019) from the Population Assessment of Tobacco and Health was conducted. Youth never tobacco users in the United States who reported exclusive past-30-day (P30D) e-cigarette or cigarette use (n = 2940, N = 5,391,642) in at least one wave were included in the current analysis. Survival analysis was used to estimate the time to the first report of three nicotine dependence indicators (i.e., "use within 30 minutes of waking"; "cravings" and "really needing to use") following the first report of P30D use. Multivariable Cox proportional hazard models were used to estimate adjusted hazard ratios (aHR). RESULTS: There were no significant differences in the time to first report of "use within 30 minutes of waking" (aHR = 1.1, 95% CI = 0.87-1.40) and "cravings" (aHR = 1.09, 95% CI = 0.81-1.47) between exclusive P30D e-cigarette use and exclusive P30D cigarette use. However, compared to exclusive P30D e-cigarette use, the hazard of first reporting "really needing to use" tobacco was 39% (aHR 1.39; 95% CI: 1.05-1.84) times higher for those who reported exclusive P30D cigarette use after controlling for covariates. CONCLUSION: Compared to exclusive P30D cigarette use, no differences in the time to first report of signs of nicotine dependence ("use within 30 minutes" and "cravings") were observed among exclusive P30D e-cigarette users. Policymakers and regulatory agencies should consider this evidence when assessing the abuse liability of e-cigarette products.

Birth-cohort patterns of e-cigarette and other tobacco use among adolescents in the US.

BACKGROUND: E-cigarette use has increased considerably among US adolescents. While many studies have described cross-sectional prevalence trends of youth e-cigarette use, less is known about cohort or generational initiation and use patterns. METHODS: We used data from the US National Youth Tobacco Survey (NYTS) from 2014 to 2022 and age-period-cohort models to analyze age-specific patterns of e-cigarette use initiation and prevalence by cohort and calendar. For comparison, we also examined initiation and prevalence for cigarettes, cigars, and smokeless tobacco, using NYTS data from 1999 to 2022. RESULTS: Age-specific e-cigarette initiation and prevalence varied considerably by calendar year and birth cohort. There was a rapid increase in e-cigarette initiation and prevalence starting with the 1995 birth cohort, peaking with the 2005 birth cohort, and showing signs of decline with more recent cohorts. In contrast, there were substantial continuous reductions in cigarette, cigar, and smokeless use initiation and prevalence by birth cohort. While the reductions in cigarette smoking started with the 1980s birth cohorts, cigar and smokeless initiation and prevalence did not decrease until the 1990-1995 cohorts. CONCLUSIONS: Despite their recent emergence, e-cigarette use has varied considerably across US adolescent cohorts. After early increases, e-cigarette use and initiation peaked with the 2005 birth cohort. These patterns are in contrast with the continuous decreases by cohort in cigarette, cigar, and smokeless use and initiation. As the tobacco product landscape continues to evolve, it will be essential to monitor patterns of use of adolescent and young adult cohorts as they age into adulthood.

The mediating roles of mental health problems and racial differences in the linkage between social media use and E-cigarette use among American youth.

OBJECTIVE: Social media use is shown to be linked to youth's e-cigarette use. However, less is known about the underlying mechanisms. This study examined the mediating roles of internalizing and externalizing problems in the association between youth's social media use and e-cigarette use, and the racial differences in the mediation association. METHODS: The study sample included 4913 U.S. youth from the Population Assessment of Tobacco and Health Study Waves 3-5 (2015-2019). Two weighted generalized structural equation models were conducted to examine the mediation pathways between youth's social media use (Wave 3) and past-30-day e-cigarette use (Wave 5) through internalizing and externalizing problems (Wave 4), respectively. Invariance tests were conducted to examine racial group differences. RESULTS: Youth with high social media use frequency were more likely to use e-cigarettes (total effect: OR = 1.20, p < 0.001 in both internalizing and externalizing models). Internalizing and externalizing problems mediated the aforementioned associations (mediation proportions: 5.05% and 5.66%, respectively). The invariance tests indicated a significant difference between White and non-White groups (both ps < 0.001), where a larger proportion of mediation was found in the non-White group (12.22% for internalizing and 11.99% for externalizing) compared to their White counterparts (2.46% for internalizing and 3.17% for externalizing). CONCLUSIONS: Mental health problems following social media use served as a risk factor for e-cigarette use among youth. Interventions aiming to improve youth's mental health could in turn temper e-cigarette use among youth social media users, and implementing tailored interventions in response to racial differences is warranted.

Distress about social problems and tobacco and cannabis use outcomes among young adults in Los Angeles County.

OBJECTIVE: To examine associations of concern, worry, and stress about discrimination, shootings/violence, and police brutality and exclusive and dual tobacco and cannabis use among young adults. METHODS: A prospective, racially/ethnically diverse cohort of young adults (n = 1960) living in Los Angeles, California completed a baseline survey in 2020 (age range: 19-23) and a follow-up survey in 2021. Exploratory factor analysis (EFA) was employed on nine variables assessing levels of concern, worry, and stress about societal discrimination, societal shootings/violence, and community police brutality at baseline. Past 30-day tobacco and cannabis use at follow-up was categorized as current exclusive tobacco, exclusive cannabis, and dual tobacco and cannabis (vs never/former) use based on eleven use variables. Multinomial logistic regressions estimated adjusted associations between each factor score (translated to standard deviation units) with exclusive and dual tobacco and cannabis use. RESULTS: The EFA produced four factor scores representing concern/worry/stress (i.e., distress) about community police brutality (F1), distress about societal shootings/violence (F2), and distress about societal discrimination (F3), as well as generalized stress about police brutality, shootings/violence, and discrimination (F4). F1, F2, and F3 were associated with subsequent exclusive current cannabis use, with F1 having the strongest association (OR: 1.35, 95% CI: 1.18-1.55), while only F1 (OR: 1.51, 95% CI: 1.27-1.78) was associated with dual tobacco and cannabis use. None of the factors were associated with exclusive tobacco use. CONCLUSIONS: Young adult concern, worry, and/or stress about social problems may increase risk of cannabis use with or without concurrent tobacco use 6-12 months later.

Transitions between smoking and vaping: Evidence (or lack thereof) on potential differences by gender and sex.

OBJECTIVE: To synthesize existing evidence on possible differential effects by sex and gender from two Cochrane reviews evaluating vaping and smoking transitions. METHODS: We screened included studies from two Cochrane reviews for studies reporting smoking outcomes based on gender or sex. The first review examines the effects of using e-cigarettes to help people quit smoking and includes randomized controlled trials and uncontrolled intervention studies published to July 2023. The second review aims to assess the evidence on the relationship between the use and availability of e-cigarettes and subsequent smoking in young people (aged 29 and younger) and includes quasi-experimental and cohort studies published to April 2023. Due to the paucity and heterogeneity of data, we report results narratively. RESULTS: 10 of 161 studies included in the two relevant reviews met our criteria. Only five reported analyzing whether observed effects or associations varied based on sex and/or gender. A further three provided relevant descriptive information, and two did not report overall outcomes regarding vaping and smoking transitions but did investigate whether these differed by sex/gender. Synthesized data were largely inconclusive, but there was some suggestion that vaping was more strongly associated with subsequent smoking in young males than females. No studies reported data on nonbinary participants. CONCLUSIONS: Despite plausible reasons why sex and gender may be moderators of vaping and smoking transitions, there is little evidence investigating this. Future studies of vaping and smoking transitions should conduct and report analyses investigating potential differences based on sex and gender.

Sex differences in tobacco use, attempts to quit smoking, and cessation among dual users of cigarettes and e-cigarettes: Longitudinal findings from the US Population Assessment of Tobacco and Health Study.

SIGNIFICANCE: A growing number of adults use more than one tobacco product, with dual use of cigarettes and e-cigarettes being the most common combination. Monitoring sex disparities in tobacco use is a public health priority. However, little is known regarding whether dual users differ by sex. METHODS: Data came from Waves 4-6 (12/2016-11/2021) of the Population Assessment of Tobacco and Health Study, a US nationally-representative longitudinal survey. This analysis included current adult dual users of cigarettes and e-cigarettes. We used weighted generalized estimating equations to assess the association between sex and (1) making a cigarette quit attempt (n = 1882 observations from n = 1526 individuals) and (2) smoking cessation (n = 2081 observations from n = 1688 individuals) across two wave pairs, adjusting for age, education, ethnicity, time-to-first cigarette after waking, and e-cigarette use frequency. RESULTS: Among US dual users, 14.1% (95% Confidence Intervals [Cl] = 11.9-16.4) of females and 23.4% (20.0-26.9) of males were young adults (aged 18-24), 11.7% (9.2-14.2) of females and 14.4% (11.6-17.2) of males had

Quantifying cigarette and e-cigarette marketing exposure among Chinese adolescents using ecological momentary assessment.

INTRODUCTION: Addressing cigarette and e-cigarette use in China is key to reducing the global tobacco epidemic. Marketing exposure is one causal factor for adolescent smoking and e-cigarette use. Currently, China restricts cigarette and e-cigarette ads in public places and online; however, there may not be full policy compliance. We collected real-time data in the natural environment to estimate how much and where Chinese adolescents - a group susceptible to smoking and e-cigarette use - are exposed to cigarette and e-cigarette marketing to inform policy responses. METHODS: In June 2022, we conducted a seven-day ecological momentary assessment (EMA) study with 15-16-year-olds (n=96) across eight Chinese cities. Participants completed up to 42 EMA surveys (6 per day), sent at random intervals outside of school hours. In each survey, participants reported whether they saw (1) displays and (2) ads in the past hour (none, cigarette, e-cigarette, both) in the past hour. We also captured the source of cigarette/e-cigarette ad exposure. RESULTS: Most participants were exposed to cigarette and/or e-cigarette displays (89.6%) or ads (79.2%) over the seven days. On average, participants reported past-hour exposure to displays 12.7 times and past-hour exposure to ads 10.8 times over the week. The most common sources of cigarette ads were public places (e.g., kiosks, supermarkets); the most common sources of e-cigarette ad exposure were social media/internet or e-cigarette stores. CONCLUSIONS: Findings highlight the need to enhance enforcement of restrictions on cigarette and e-cigarette ads in public places and online in China and extend restrictions to ban displays. IMPLICATIONS: Marketing exposure is a causal factor in youth smoking and e-cigarette use. We used ecological momentary assessments to estimate cigarette and e-cigarette display and ad exposure among Chinese adolescents. On average, participants reported past-hour exposure to cigarette and/or e-cigarette displays 13 times and past-hour exposure to cigarette and/or e-cigarette ads 11 times over one week. Most saw ads in public places and online. Results suggest strengthening implementation of China's ban on cigarette and e-cigarette ads in public places and online and banning product displays. These are policy responses that can contribute to reducing adolescent cigarette and e-cigarette uptake in China.

A review of the toxicity of ingredients in e-cigarettes, including those ingredients having the FDA's "Generally Recognized as Safe (GRAS)" regulatory status for use in food.

INTRODUCTION: Some firms and marketers of electronic cigarettes (e-cigarettes; a type of electronic nicotine delivery system (ENDS)) and refill liquids (e-liquids) have made claims about the safety of ingredients used in their products based on the term "GRAS or Generally Recognized As Safe" (GRAS). However, GRAS is a provision within the definition of a food additive under section 201(s) (21 U.S.C. 321(s)) of the U.S. Federal Food Drug and Cosmetic Act (FD&C Act). Food additives and GRAS substances are by the FD&C Act definition intended for use in food, thus safety is based on oral consumption; the term GRAS cannot serve as an indicator of the toxicity of e-cigarette ingredients when aerosolized and inhaled (i.e., vaped). There is no legal or scientific support for labeling e-cigarette product ingredients as "GRAS". This review discusses our concerns with the GRAS provision being applied to e-cigarette products and provides examples of chemical compounds that have been used as food ingredients but have been shown to lead to adverse health effects when inhaled. The review provides scientific insight into the toxicological evaluation of e-liquid ingredients and their aerosols to help determine the potential respiratory risks associated with their use in e-cigarettes. IMPLICATIONS: The rise in prevalence of e-cigarette use and emerging evidence of adverse effects, particularly on lung health, warrant assessing all aspects of e-cigarette toxicity. One development is manufacturers' stated or implied claims of the safety of using e-cigarette products containing ingredients determined to be "Generally Recognized As Safe" (GRAS) for use in food. Such claims, typically placed on e-cigarette product labels and used in marketing, are unfounded, as pointed out by the United States Food and Drug Administration (FDA)1 and the Flavor and Extract Manufacturers Association (FEMA)2. Assessment of inhalation health risks of all ingredients used in e-liquids, including those claimed to be GRAS, is warranted.

The effect of nicotine-containing products on peri-implant tissues: A systematic review and network meta-analysis.

INTRODUCTION: Smokers have a higher chance of developing peri-implant diseases and are therefore considered an at-risk population. Our aim was to compare peri-implant characteristics in users of electronic cigarettes (EC), waterpipes (WP), cigarettes (CS), smokeless tobacco (ST), and non-smokers (non-users of any nicotine and tobacco product; NS). METHODS: A systematic search of four electronic databases (PubMed, EMBASE, Web of Science, CENTRAL) was performed until April 2023, restricted to English language. Thirty-nine observational studies were included in the qualitative synthesis, of which 32 studies were included in a Bayesian network meta-analysis. Using a predesigned form, two researchers independently collected data about marginal bone loss (MBL), probing pocket depth (PPD), plaque index (PI), bleeding on probing (BOP), modified plaque index (mPI), probing pocket depth > 4mm (PPD>4), gingival index (GI), peri-implant sulcular fluid (PISF) volume, and TNF-α and IL-1ß levels. QUIPS and CINeMA were used to evaluate the risk of bias and certainty of evidence. RESULTS: NS had the smallest MBL. Most nicotine-containing product users had significantly higher MBL (CS, MD:1.34 CrI: 0.85, 1.79; WP, MD:1.58 CrI: 0.84, 2.35; ST, MD:2.53, CrI: 1.20, 3.87) than NS. EC did not show significant difference compared to NS (MD:0.52 CrI: -0.33, 1.36). In secondary outcomes NS were ranked in first place. Subset analysis based on smoking habit, implant duration, and maintenance control revealed no differences in ranking probability. CONCLUSION: Most nicotine-containing product users presented worse peri-implant parameters compared to non-smokers, while EC users did not show significant differences to NS in many outcomes. IMPLICATION: Alternative nicotine-containing products are gaining popularity and are often considered less harmful by the general public compared to traditional cigarettes. This is the first network meta-analysis comparing users of four nicotine-containing products and non-smokers. This study shows that CS, WP and ST have a detrimental effect on the overall health of peri-implant tissues. EC users also presented inferior parameters compared to NS, however, the difference was not significant in many outcomes. It is essential to educate patients who are using nicotine-containing products, and to provide proper maintenance and appropriate cessation support. Well-designed multi-armed studies are needed for direct comparison of different products, including heated tobacco products. Greater transparency of confounding factors is needed regarding smoking habit and oral hygiene.

A randomized controlled trial of potential tobacco policies prohibiting menthol flavor in cigarettes and e-cigarettes: a study protocol.

BACKGROUND: Menthol cigarette use remains a large public health problem and disproportionately affects Black adults in the United States. The Food and Drug Administration has proposed prohibiting menthol flavor in cigarettes to protect public health. However, e-cigarettes are available in menthol flavor and are a popular alternative product adults might switch to if menthol is prohibited in cigarettes. Research is needed to understand how availability of menthol (vs. tobacco) flavored e-cigarettes could impact cigarette use among adults who smoke menthol cigarettes. METHODS: We will recruit 150 adults who currently smoke menthol cigarettes and will randomize them to 1 of 3 conditions modeling different regulatory scenarios. We will recruit equal numbers of participants identifying as Black vs. non-Black and will stratify randomization by race. To promote standardization and adherence, cigarette and e-cigarette products will be provided for 8 weeks based on the assigned condition: (A) no menthol restriction (menthol cigarette and menthol flavored e-cigarette), (B) menthol prohibited in cigarettes only (non-menthol cigarette and menthol flavored e-cigarette), (C) menthol prohibited in both cigarettes and e-cigarettes (non-menthol cigarette and tobacco flavored e-cigarette). A follow-up visit will occur at week 12 to assess tobacco use status. The study aims are to (1) examine the impact of prohibiting menthol flavor in cigarettes and e-cigarettes on smoking behavior and (2) investigate whether outcomes differ by race to understand the impact of menthol policies on Black (vs. non-Black) individuals given high rates of menthol cigarette use in this population. The primary outcome will evaluate changes in the number of cigarettes smoked per day during the 8-week study period and will examine differences by regulatory scenario. Secondary outcomes will compare percent days smoke-free, changes in nicotine dependence, and motivation, confidence, and intentions to quit smoking by the regulatory scenarios. We will examine whether changes in the outcomes differ by Black vs. non-Black participants to compare the magnitude of the effect of the various menthol policy scenarios by race. DISCUSSION: Results will contribute critical information regarding menthol in cigarettes and e-cigarettes to inform regulatory policies that maximize reductions in cigarette smoking and reduce tobacco-related health disparities. TRIAL REGISTRATION: NCT05259566. Yale IRB protocol #2000032211, last approved 12/8/2023.

Characterization of mass distribution in a biomimetic aerosol exposure system.

OBJECTIVE: Lack of biomimicry in geometry and flow conditions of emissions systems for analytical testing and biological exposure has led to fundamental limitations, including a poor understanding of dose delivered to specific airway locations. This work characterizes mass distribution of a JUUL® brand e-cigarette in a Biomimetic Aerosol Exposure System (BAES). MATERIALS AND METHODS: A combination of mass balance, direct measurements, and inferences based on direct measurements were used to characterize regional and local dose as a function of system flow path configuration and emissions topography profile. RESULTS: Doses produced by the emissions topography profile with only puffing were significantly different from profiles with clean air inhalation following puffs. Mass characterization results support that dose can be manipulated using flow path geometry. Local and regional deposition was mapped throughout the system. DISCUSSION AND CONCLUSIONS: We estimate the fraction of yield to the mouth deposited at several locations throughout the system for a variety of puffing and respiration topographies and show that emissions topography profile and system flow path geometry affect dose. This work provides proof-of-concept for assessing mass distribution as a function of aerosol generator (e-cigarette product), user airway geometry, and inhalation and puffing topography.

Vaping cessation support recommendations from adolescents who vape: a qualitative study.

BACKGROUND: Youth vaping is a serious public health concern, being more prevalent than any other tobacco use. To inform cessation interventions, we explored what adolescents perceive as their reasons for quitting and strategies to help them quit. METHOD: Semi-structured interviews were conducted with a convenience sample of 11 adolescents reporting vaping in the past 90 days and recruited from a high school in Massachusetts. Interviews were transcribed and dual-coded. Inductive thematic analysis was employed, and thematic summaries were prepared. RESULTS: Reasons adolescents reported for quitting included cost, experiencing "nic-sick" from nicotine withdrawal or excess intake, negative impacts on mood, concentration, or health, and experiencing symptoms of nicotine dependence. Nearly all tried to quit multiple times. Barriers to quitting included exposure to vaping, access to vape products, stress, and "cool" new products or flavors. Quit strategies included avoiding others vaping, seeking social support to quit, addressing peer pressure to continue vaping, learning successful quit strategies from peers, and using distraction strategies or alternatives to vaping. CONCLUSION: Many adolescents who vape want to quit, and most have tried multiple times. Interventions need to engage adolescents with varying reasons to quit, barriers, and quit strategy preferences. CLINICAL TRIAL REGISTRATION: This study is registered through ClinicalTrials.gov. The trial registration number is NCT05140915. The trial registration date is 11/18/2021.

Association between health-related social media use and E-cigarette use among current cigarette users: the roles of anti-tobacco messages and harm perception.

BACKGROUND: The popularity of e-cigarettes is on the rise among current cigarette users. Therefore, there are concerns about their health implications. This study examined the impact of health-related social media use on e-cigarette use among current cigarette users. It assesses the mediating influence of online anti-tobacco messages and the moderating role of the harm perception of e-cigarettes. METHODS: This study was focused on 563 current cigarette users from the 2022 Health Information National Trends Survey (HINTS). Three tasks were performed: (1) assessing the direct and indirect impacts of health-related social media use on e-cigarette use among current cigarette users, (2) exploring the mediating role of exposure to online anti-tobacco messages, and (3) examining the moderating influence of e-cigarette harm perception on the path from anti-tobacco messages to e-cigarette use. RESULTS: Health-related social media use was positively associated with current cigarette users' e-cigarette use directly (bp = 0.183, p < .01) and indirectly through exposure to online anti-tobacco messages (bp = 0.023, 95% CI: [0.001, 0.051]). Harm perception of e-cigarettes moderated the relationship between online exposure to anti-tobacco messages and e-cigarette use (bp=-0.467, p < .01). The relationship appeared weaker for individuals who perceived greater harm from e-cigarettes. CONCLUSIONS: Health-related social media use positively correlates with e-cigarette use among current cigarette users through exposure to online anti-tobacco messages. The perceived harm of e-cigarettes moderates this indirect path. These findings have implications for public health interventions aimed at smoking cessation.

Implications of Switching from Conventional to Electronic Cigarettes on Quality of Life and Smoking Behaviour: Results from the EQualLife Trial.

INTRODUCTION: Electronic cigarettes and "vaping" have become popular since their appearance in Europe and the USA in approximately 2006. They are often perceived as having fewer health risks than conventional cigarettes, which makes them of interest as a support tool in smoking cessation. However, its efficacy regarding cessation or reduction of smoking under real-life conditions remains controversial. Our objective was to clarify this question in an observational study of smoking habits after initiating vaping without targeted intervention, as compared to a validated cessation programme. METHODS: From October 2015 to April 2018, 80 subjects (60 in the e-cigarette group and 20 in the supervised smoking cessation group) were included in two trial visits, one at the start of the trial and the second after 3 months, plus 4 questionnaire surveys: at the start of the trial and after a 1, 2, and 3 month period. The questionnaire included a nicotine use inventory, a modified Fagerström test for nicotine dependence, and the WHO-QOL-BREF survey. RESULTS: E-cigarettes were effective, leading to a significant (p < 0.03) reduction (p < 0.03) in tobacco consumption and nicotine dependence, with an abstinence rate of 43% after 3 months. Compared to participants in the smoking cessation programme, their use was not associated with an improvement in quality of life during the quitting attempt, and there were no significant differences in clinical symptoms between groups. The reduction in nicotine dependence was more pronounced (p < 0.012) for the smoking cessation programme, with higher abstinence rates (p = 0.011 after 12 weeks) and lower (p < 0.003) remaining tobacco consumption compared to electronic cigarettes. DISCUSSION/CONCLUSIONS: The use of electronic cigarettes reduced nicotine dependence and tobacco consumption, but a supervised smoking cessation programme was superior in terms of achieved cessation in both regards. Electronic cigarettes did not improve the quality of life. Since e-cigarettes could be associated with long-term health risks, their usefulness in smoking cessation remains questionable, and a professionally guided and validated smoking cessation programme still appears to be superior and preferable, in terms of achieved cessation. Although this trial is limited regarding the number of participants and follow-up time, it highlights the need for additional, large clinical trials evaluating the efficacy of e-cigarettes for smoking cessation in comparison to a professionally guided smoking cessation programme.

Time-Varying Determinants of Changes in E-Cigarette Relative Harm Perception Among US Young Adults.

BACKGROUND: Current e-cigarette use has increased among young adults in the USA despite a consistent decrease in perceiving e-cigarettes as less harmful than cigarettes over time. This study examined time-varying predictors associated with the changes in e-cigarette relative harm perception over time among US young adults. METHODS: Data were from the 2013-2018 Population Assessment of Tobacco and Health (PATH) Study for young adults (18-24 years). A time-varying effect model (TVEM) was applied to examine the association between the relative harm perception change and the associated time-varying predictors. RESULTS: Of the 8427 young adults, the prevalence of those who perceived e-cigarettes as less harmful than cigarettes decreased from 50.3% in Wave 1 (2013-2014) to 27.7% in Wave 4 (2016-2018). Young adults who were male were more likely to perceive e-cigarettes as less harmful than cigarettes over time (OR = 1.58; 95%CI, 1.53-1.64). In addition, the changes in e-cigarette relative harm perception were less noticeable among those with advanced degrees, who had non-combustible smoke-free home rules, who held negative tobacco-related attitudes, and those who were current e-cigarette users or ever used alcohol (all p values < 0.05). CONCLUSIONS: A decline was observed in US young adults who perceived e-cigarettes as less harmful than cigarettes from the PATH Study across four waves (2013-2018). The study findings underscore the importance of risk communication that focuses on harm perception profiles and the need for appropriate interventions to balance the considerations of e-cigarette use among young adults.