Alveolar macrophage function is impaired following inhalation of berry e-cigarette vapor.

In the lower respiratory tract, the alveolar spaces are divided from the bloodstream and the external environment by only a few microns of interstitial tissue. Alveolar macrophages (AMs) defend this delicate mucosal surface from invading infections by regularly patrolling the site. AMs have three behavior modalities to achieve this goal: extending cell protrusions to probe and sample surrounding areas, squeezing the whole cell body between alveoli, and patrolling by moving the cell body around each alveolus. In this study, we found Rho GTPase, cell division control protein 42 (CDC42) expression significantly decreased after berry-flavored e-cigarette (e-cig) exposure. This shifted AM behavior from squeezing to probing. Changes in AM behavior led to a reduction in the clearance of inhaled bacteria, Pseudomonas aeruginosa. These findings shed light on pathways involved in AM migration and highlight the harmful impact of e-cig vaping on AM function.

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.

Maternal third hand exposure to e-cigarette vapor alters lung and bone marrow immune cell responses in offspring in the absence or presence of flu infection.

There is increasing evidence that third hand exposure to e-cigarette vapor (e-vapor) can have detrimental effects on the lungs. However, whether maternal exposure during pregnancy results in harmful changes to the offspring is unknown. Using two different e-cigarette settings (low versus high power), BALB/c mice were subjected to third hand e-vapor (e-vapor deposited onto towels, towels changed daily) in the absence or presence of nicotine, before, during, and after pregnancy. Male adult offspring were then infected with mouse-adapted influenza A virus (A/PR/8/34 H1N1) and lung and bone marrow immune cell responses assessed 7 days post infection. Maternal third hand exposure to low power (MLP) or high power (MHP) e-vapor with nicotine (MLP+NIC and MHP+NIC, respectively) increased the percentage of lung immune cells and neutrophils in the bone marrow. Interestingly, Flu-infected offspring from MLP+NIC and MHP+NIC groups had lower percentages of lung alveolar macrophages, and more pronounced increases in neutrophils in the bone marrow, when compared to offspring from MSham Flu controls. Flu infection also decreased the percentage of lung CD4+ T cells and increased the percentage of lung CD8+ T cells, irrespective of maternal exposure (MLP-/+NIC and MHP-/+NIC). Significantly, both MLP+NIC and MHP+NIC resulted in blunted activation of lung CD4+ T cells, but only MLP+NIC caused blunted activation of lung CD8+ T cells. Together, we show for the first time that maternal third hand exposure to e-vapor results in significant, long-lived effects on lung and bone marrow immune cell responses in offspring at baseline and in response to Flu infection.

Chronic exposure to E-cigarette aerosols potentiates atherosclerosis in a sex-dependent manner.

Despite being designed for smoking cessation, e-cigarettes and their variety of flavors have become increasingly attractive to teens and young adults. This trend has fueled concerns regarding the potential role of e-cigarettes in advancing chronic diseases, notably those affecting the cardiovascular system. E-cigarettes contain a mixture of metals and chemical compounds, some of which have been implicated in cardiovascular diseases like atherosclerosis. Our laboratory has optimized in vivo exposure regimens to mimic human vaping patterns. Using these established protocols in an inducible (AAV-PCSK9) hyperlipidemic mouse model, this study tests the hypothesis that a chronic exposure to e-cigarette aerosols will increase atherosclerotic plaques. The exposures were conducted using the SCIREQ InExpose™ nose-only inhalation system and STLTH or Vuse products for 16 weeks. We observed that only male mice exposed to STLTH or Vuse aerosols had significantly increased plasma total cholesterol, triglycerides, and LDL cholesterol levels compared to mice exposed to system air. Moreover, these male mice also had a significant increase in aortic and sinus plaque area. Male mice exposed to e-cigarette aerosol had a significant reduction in weight gain over the exposure period. Our data indicate that e-cigarette use in young hyperlipidemic male mice increases atherosclerosis in the absence of significant pulmonary and systemic inflammation. These results underscore the need for extensive research to unravel the long-term health effects of e-cigarettes.

Single-cell transcriptomics reveals e-cigarette vapor-induced airway epithelial remodeling and injury.

BACKGROUND: In recent years, e-cigarettes have been used as alternatives among adult smokers. However, the impact of e-cigarette use on human bronchial epithelial (HBE) cells remains controversial. METHODS: We collected primary HBE cells of healthy nonsmokers and chronic obstructive pulmonary disease (COPD) smokers, and analyzed the impact of e- cigarette vapor extract (ECE) or cigarette smoke extract (CSE) on HBE cell differentiation and injury by single-cell RNA sequencing, immunostaining, HE staining, qPCR and ELISA. We obtained serum and sputum from healthy non- smokers, smokers and e-cigarette users, and analyzed cell injury markers and mucin proteins. RESULTS: ECE treatment led to a distinct differentiation program of ciliated cells and unique patterns of their cell-cell communications compared with CSE. ECE treatment caused increased Notch signaling strength in a ciliated cell subpopulation, and HBE cell remodeling and injury including hypoplasia of ciliated cells and club cells, and shorter cilia. ECE-induced hypoplasia of ciliated cells and shorter cilia were ameliorated by the Notch signaling inhibition. CONCLUSIONS: This study reveals distinct characteristics in e-cigarette vapor-induced airway epithelial remodeling, pointing to Notch signaling pathway as a potential targeted intervention for e-cigarette vapor-caused ciliated cell differentiation defects and cilia injury. In addition, a decrease in SCGB1A1 proteins is associated with e- cigarette users, indicating a potential lung injury marker for e-cigarette users.

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.

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.

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.

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

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

Decoding Vaping: Empowering Youth through Media Literacy Based E-Cigarette Educational Program.

INTRODUCTION: E-cigarette industry's marketing and social media efforts have promoted adolescent vaping. We developed and pilot-tested an anti-vaping media literary program - MediaSense. METHODS: In addition to employing the Community-Based Participatory Research approach for program development, we applied a prospective, interventional, and single-arm design to assess the impact of MediaSense among students from five middle and high schools. Data were collected through REDCap surveys administered before and after the intervention. We performed generalized linear mixed models and median analysis to evaluate changes in vaping media literacy (i.e., Authors and Audiences [vAA], Messages and Meanings [vMM], and Representation and Reality [vRR]), knowledge, harm perception, and susceptibility to e-cigarette use before and after the intervention. RESULTS: A total of 384 students aged 11-18 years completed the pre-post survey assessment. After the intervention, students exhibited significantly improved vaping media literacy across all three domains (vAA,fold change [FC]=150%, p<0.0001; vMM, FC=143%, p<0.0001; vRR, FC=133%, p=0.0007). The intervention was associated with a reduction of vaping susceptibility (adjusted odds ratio [AOR]=0.7, p=0.04) and improvement in harm perception (AOR=1.6, p=0.009), knowledge of flavored e-cigarettes (AOR=4.4, p<0.0001) and Tobacco 21 policy (AOR=6.2, p<0.0001). Further mediation analysis unveiled the pathway of the intervention on reduction of vaping susceptibility through media literacy (ßindirect=-0.03, p=0.003) and harm perception enhancement (ßindirect=-0.02, p=0.03). CONCLUSION: The MediaSense program showed promise in vaping prevention among adolescents by reducing vaping susceptibility. Comprehensive vaping media literacy education, especially interventions aimed at decoding misleading marketing information and addressing emerging marketing themes, provides valuable evidence in curbing adolescent vaping. IMPLICATIONS: MediaSense (Media Education for Sensible Evaluation and Nurturing Substance-free Experiences) represents a promising e-cigarette education program designed for adolescent vaping prevention. The findings of this study highlight the positive impact of the program on media literacy, harm perception, and knowledge of tobacco control policies.

Variation in Relative Risk Perceptions and Tobacco Use by Race and Socioeconomic Status among Older Adults who Smoke: Evidence from the Population Assessment of Tobacco and Health (PATH) Study.

INTRODUCTION: Older adults who smoke face significant risk of tobacco-related disease and hold misperceptions about health risks posed by nicotine product use. This study examined whether socioeconomic status and race are associated with variation in cigarette/e-cigarette relative risk perceptions, whether relative risk perceptions are associated with tobacco use behaviors, and whether socioeconomic status and race moderate associations between perceptions and use behaviors. METHODS: Five waves of PATH Study yielded data from 1,879 adults >55 who smoked within the past 30 days during Wave 1. Adjusted longitudinal logistic models estimated associations between higher vs. lower SES ("low-SES": less than high school diploma/GED. and annual household income<$25,000) and race (White vs. Black/African American; AA) and e-cigarette/cigarette relative risk perceptions, behavioral intentions, and e-cigarette use. RESULTS: Lower-SES adults were more likely to report e-cigarettes were very/extremely harmful to health (AOR: 1.74, p<0.01) and less likely to report e-cigarettes were less harmful than cigarettes (AOR: 0.65, p<0.01). Black/AA adults were less likely to report that e-cigarettes were less harmful than cigarettes. Participants rating e-cigarettes as equally/more harmful than cigarettes exhibited lower odds of intending to quit smoking or switch to e-cigarettes. Finally, Black/AA adults who also perceived e-cigarettes equally/more harmful than cigarettes exhibited greater odds of trying to reduce rather than quit smoking (AOR: 1.58, p=0.02). CONCLUSIONS: Many older adults who smoke perceive e-cigarettes as equally or more harmful than cigarettes, particularly low-SES and Black/AA older adults. Differences in relative risk perceptions among high priority populations could negatively influence cessation attempts and switching behaviors. IMPLICATIONS: This study found that Black/AA and low-SES older adults who smoke cigarettes were more likely to perceive e-cigarettes as harmful or more harmful than cigarettes. The absence of accurate, evidence-based information regarding the relative health risks associated with the long-term use of various tobacco products may impede policy efforts to reduce disparities in smoking-related disease through increased cessation and/or harm reduction.

Cost Comparison and Spending on Tobacco Products: Evidence from A Nationally Representative Sample of Adult E-Cigarette Users.

INTRODUCTION: Over 20 states and local jurisdictions in the U.S. have imposed e-cigarette taxes. It is important to evaluate how adult vapers, including those who also smoke respond to e-cigarette taxation. The purpose of this study is to examine factors associated with adult vapers' cost comparison between e-cigarettes and cigarettes (i.e., which one is perceived to be more expensive) and expenditures (i.e., dollars spent) on these two products. METHODS: We recruited a nationally representative sample of 801 adult e-cigarette users in the U.S., who participated in an online survey in April-May 2023. Nested-ordered logit and ordinary least squares regressions were used in analysis. RESULTS: On average, adult vapers spent $82.22 per month on e-cigarettes, and dual users spent $118.77 per month on cigarettes. More frequent e-cigarette use, lower state-level e-cigarette taxes, age and exclusive use of rechargeable tank systems with e-liquids were associated with considering e-cigarettes as less expensive than cigarettes. Exclusive use of tank systems was associated with lower e-cigarette spending. Adults who used e-cigarettes more frequently preferred to report weekly (versus monthly) spending on e-cigarettes; among dual users, everyday smokers were more likely to think of weekly (versus monthly) spending on cigarettes compared to someday smokers. CONCLUSIONS: Among US adult vapers, tobacco use frequency and e-cigarette device type are closely related to cost measures; e-cigarette taxes are associated with cost comparison between e-cigarettes and cigarettes, suggesting potential financial disincentive for vaping. Policymaker may consider imposing differential taxes by e-cigarette product types due to their different costs to consumers. IMPLICATIONS: This study provides supportive evidence that e-cigarette taxes may impact how vapers compare the costs of e-cigarettes relative to cigarettes. Given different expenditures and cost comparisons by e-cigarette device types, tax and policy design may need to take into consideration of e-cigarette device types. We also found that indoor tobacco use restrictions in shared housing may reduce vaping, and future research is needed. The associations between socio-demographics and cost comparison and expenditures reflect known patterns in price responsiveness and vaping prevalence. Cost comparison and expenditures are related measures, which may further reflect product affordability.

Assessing nicotine pharmacokinetics of new generation tobacco products and conventional cigarettes: a systematic review and meta-analysis.

INTRODUCTION: New generation tobacco products (NGPs) hold promises as modified-risk alternatives to conventional cigarettes (CCs), given their comparable characteristics. This study investigated the nicotine pharmacokinetics (PK) of NGPs, encompassing closed pod systems, refillable e-cigarettes (ECs), and heated tobacco products (HTPs), in comparison to CCs through systematic review and meta-analysis. METHODS: A comprehensive search was conducted on PubMed, Embase, and Web of Science for articles published between January 2013 and July 2023. Maximum nicotine concentration (Cmax), time to the peak concentration (Tmax), and total nicotine exposure (area under the concentration-time curve, AUC) were extracted to evaluate nicotine delivery PK. Random effects meta-analyses were performed to determine pooled standardized mean differences (SMD), facilitating a comparison of PK profiles between NGPs and CCs. Subgroup analyses exploring flavors and nicotine concentrations across NGPs, and CCs were also conducted. RESULTS: The meta-analysis incorporated 30 articles with 2728 participants. Cmax and AUC were significantly lower for NGPs, while Tmax demonstrated statistical similarity compared to CCs. Among three NGPs, Cmax and AUC were lower for closed pod systems and refillable ECs. In HTPs, Cmax was statistically similar while AUC was lower compared to CCs. Tmax was statistically similar in closed pod systems and HTPs compared to that of CCs. No significant difference was observed in the comparisons of PK between each type of NGPs versus CCs. CONCLUSIONS: NGPs delivered less nicotine than CCs but reached Cmax over a similar timeframe, indicating that NGPs may serve as modified-risk alternatives with lower nicotine delivery to CCs for craving relief and smoking cessation. IMPLICATION: This study suggested that NGPs, such as the closed pod systems, the refillable ECs, and the HTPs, delivered either lower or comparable nicotine levels and achieved peak nicotine concentration at a similar rate as CCs. Our findings carry implications that NGPs can serve as modified-risk nicotine alternative to CCs in helping smokers to manage cravings and potentially quit smoking, thereby highlighting their value in the field of tobacco harm reduction.