Addressing Cardiovascular Toxicity Risk of Electronic Nicotine Delivery Systems in the Twenty-First Century: "What Are the Tools Needed for the Job?" and "Do We Have Them?"

Cigarette smoking is positively and robustly associated with cardiovascular disease (CVD), including hypertension, atherosclerosis, cardiac arrhythmias, stroke, thromboembolism, myocardial infarctions, and heart failure. However, after more than a decade of ENDS presence in the U.S. marketplace, uncertainty persists regarding the long-term health consequences of ENDS use for CVD. New approach methods (NAMs) in the field of toxicology are being developed to enhance rapid prediction of human health hazards. Recent technical advances can now consider impact of biological factors such as sex and race/ethnicity, permitting application of NAMs findings to health equity and environmental justice issues. This has been the case for hazard assessments of drugs and environmental chemicals in areas such as cardiovascular, respiratory, and developmental toxicity. Despite these advances, a shortage of widely accepted methodologies to predict the impact of ENDS use on human health slows the application of regulatory oversight and the protection of public health. Minimizing the time between the emergence of risk (e.g., ENDS use) and the administration of well-founded regulatory policy requires thoughtful consideration of the currently available sources of data, their applicability to the prediction of health outcomes, and whether these available data streams are enough to support an actionable decision. This challenge forms the basis of this white paper on how best to reveal potential toxicities of ENDS use in the human cardiovascular system-a primary target of conventional tobacco smoking. We identify current approaches used to evaluate the impacts of tobacco on cardiovascular health, in particular emerging techniques that replace, reduce, and refine slower and more costly animal models with NAMs platforms that can be applied to tobacco regulatory science. The limitations of these emerging platforms are addressed, and systems biology approaches to close the knowledge gap between traditional models and NAMs are proposed. It is hoped that these suggestions and their adoption within the greater scientific community will result in fresh data streams that will support and enhance the scientific evaluation and subsequent decision-making of tobacco regulatory agencies worldwide.

Trends in Current Electronic Cigarette Use Among Youths by Age, Sex, and Race and Ethnicity.

This cross-sectional study examines prevalence of electronic cigarette use among youths by age, sex, and race and ethnicity from 2013 to 2022.

Associations of Prevalence of E-cigarette Use With Quit Attempts, Quit Success, Use of Smoking Cessation Medication, and the Overall Quit Rate Among Smokers in England: A Time-Series Analysis of Population Trends 2007-2022.

INTRODUCTION: This study aimed to (1) provide up-to-date estimates of how changes in the prevalence of e-cigarette use have been associated with changes in smoking cessation activities and use of licensed treatments among smokers in England and (2) explore any changes in these associations over time. METHODS: Data were aggregated quarterly on 67 548 past-year smokers between Q1-2007 and Q4-2022. Explanatory variables were the prevalence of (1) current e-cigarette use among smokers and (2) e-cigarette use during a quit attempt. Outcomes were rates of quit attempts and overall quits among past-year smokers, and the quit success rate and use of licensed treatments among those who made a quit attempt. RESULTS: The success rate of quit attempts increased by 0.040% (95% CI 0.019; 0.062) for every 1% increase in the prevalence of e-cigarette use during a quit attempt. No clear evidence was found for an association between current e-cigarette use and the quit attempt rate (Badj = 0.008 [95% CI -0.045; 0.061]) or overall quit rate (Badj = 0.063 [-0.031; 0.158]); or between use of e-cigarettes during a quit attempt and the overall quit rate (Badj = 0.030 [-0.054; 0.114]), use of prescription medication (varenicline/bupropion/nicotine replacement therapy [NRT]: Badj = -0.036 [-0.175; 0.102]), or use of over-the-counter NRT (Badj = -0.052 [-0.120; 0.015]). There was no clear evidence this pattern of associations has changed substantially over time. CONCLUSIONS: Changes in the prevalence of e-cigarette use in England through 2022 have been positively associated with the success rate of quit attempts but not clearly associated with the quit attempt rate, overall quit rate, or use of licensed smoking cessation treatments. IMPLICATIONS: If the association between the increase in e-cigarette use and the quit success rate is causal, then the use of e-cigarettes in quit attempts has helped in the region of 30 000 to 50 000 additional smokers in England to successfully quit each year since they became popular in 2013, over and above the number who were quitting before the advent of e-cigarettes.

Trends in Urinary Biomarkers of Exposure to Nicotine and Carcinogens Among Adult e-Cigarette Vapers vs Cigarette Smokers in the US, 2013-2019.

This study assesses temporal trends of biomarkers among adult nicotine and nonnicotine e-cigarette users and cigarette smokers.

An Epidemic Supplanted by a Pandemic: Vaping-Related Illness and COVID-19.

Before the coronavirus disease 2019 (COVID-19) pandemic, vaping-related illness was the prevailing public health concern. The incidence of vaping-related illnesses-mainly e-cigarette, or vaping, product use-associated lung injury (EVALI)-went from a peak in September 2019 to a low in February 2020, and the Centers for Disease Control and Prevention decided to discontinue the collection of EVALI case reports. Despite the decrease in EVALI with the arrival of COVID-19, EVALI should still be considered a differential diagnosis for people with COVID-19 for reasons outlined in this review. This narrative review describes vaping devices, summarizes the adverse health effects of vaping on the lungs and other systems, considers the potential interplay between vaping and COVID-19, and highlights gaps in knowledge about vaping that warrant further research.

Age of e-cigarette initiation in USA young adults: Findings from the Population Assessment of Tobacco and Health (PATH) study (2013-2017).

INTRODUCTION: There is a lack of research prospectively estimating the age of e-cigarette initiation in U.S. young adults. METHODS: Secondary analysis of PATH young adults across 2013-2017 (waves 1-4) were conducted. We prospectively estimated age of initiation of: ever, past 30-day, and fairly regular e-cigarette use using weighted interval-censoring survival analyses. Interval-censoring Cox proportional hazard models adjusting for sex, race/ethnicity, and previous use of six other tobacco products (cigarettes, traditional cigars, filtered cigars, cigarillos, hookah, and smokeless tobacco) were fitted for each of the three e-cigarette initiation outcomes. RESULTS: Among never e-cigarette users, by age 21, 16.8% reported ever use, 7.2% reported past 30-day use, and 2.3% reported fairly regular e-cigarette use. Males had increased risk of initiating ever, past 30-day, and fairly regular e-cigarette use at earlier ages compared to females. Hispanic young adults had increased risk of initiating ever and past 30-day e-cigarette use at earlier ages compared to Non-Hispanic White young adults. Previous use of other tobacco products before e-cigarette initiation increased the risk of an earlier age of e-cigarette initiation. CONCLUSION: Prevention and education campaigns should focus on young adults in order to alleviate the public health burden of initiating e-cigarette use at earlier ages.

Use of heated tobacco products by people with chronic diseases: The 2019 JASTIS study.

Heated tobacco products (HTPs) have become popular recently. People with chronic disease, such as diabetes, cardiovascular disease (CVD), chronic obstructive pulmonary disease (COPD) and cancer, should quit smoking for treatment and recurrence of tobacco-related diseases. However, they have difficulty in quitting smoking, and they may start HTPs use to quit smoking. The purpose of this study is to examine the use of HTPs in people with chronic disease. We used data from an internet study, the Japan Society and New Tobacco Internet Survey (JASTIS). We analyzed 9,008 respondents aged 15-73 years in 2019 using logistic regression. Current use of tobacco products was defined as use within the previous 30 days. Prevalence of current HTP use including dual use and dual use with cigarettes was 9.0% and 6.1% respectively in total. By disease: hypertension 10.2% and 7.4%, diabetes 15.9% and 12.3%, CVD 19.2% and 15.7%, COPD 40.5% and 33.3%, and cancer 17.5% and 11.9%. Diabetes, CVD, COPD, and cancer were positively associated with current use of HTPs (odds ratios (ORs) and 95% confidence intervals (CIs): 1.48 (1.06, 2.07), 2.29 (1.38, 3.80), 3.97(1.73, 9.11), and 3.58(1.99, 6.44), respectively) and dual use of cigarettes and HTPs (ORs and 95% CIs: 2.23 (1.61, 3.09), 3.58 (2.29, 5.60), 7.46 (3.76, 14.80), and 2.57 (1.46, 4.55), respectively) after adjusting for confounders. People with chronic disease were more likely to use HTPs and HTPs together with cigarettes. Further research on the smoking situation of HTPs in patients with chronic diseases is necessary.

Trends in various e-cigarette devices used by high school adolescents from 2017-2019.

BACKGROUND: Adolescent e-cigarette use has increased recently; however, little is known about trends in use of specific devices by youth. This study aims to 1) compare rates of e-cigarette device use over time, 2) examine changes in frequency of device use, and 3) identify predictors of device use. METHODS: Cross-sectional surveys were distributed school-wide across 4 diverse Connecticut high-schools in 2017, 2018, 2019 and assessed current (i.e., past-30-day) use of various e-cigarette devices: disposables/cig-a-likes, vape pens, mods, JUULs, and other rechargeable pod devices (added in 2018 and 2019). Analyses compared rates of device use and frequency (i.e., number of days used in past 30) over time. Multivariable logistic regression models examined demographic and tobacco use characteristics (e.g., age first trying e-cigarettes) as predictors of current use of each device type in 2019. RESULTS: From 2017-2019, rates of using JUUL, disposables/cig-a-likes, and vape pens increased significantly, while use of mods and other pod devices decreased (ps<.001). Over 59 % of youth reported using more than one e-cigarette device in 2019. Over time, more youth were frequent users (using ≥20 out of 30 days) of disposable/cig-a-likes (32 % to >46 %) and JUUL (28 % to >35 %) devices. In multivariable models, first trying e-cigarettes at a younger age was associated with current use of disposable/cig-a-like, vape pens, mods, and other rechargeable pod devices. CONCLUSIONS: From 2017-2019, JUUL, disposable/cig-a-like, and vape pens increased in popularity and were used frequently. Tobacco regulations designed to reduce youth use should consider various device types.

Use of E-cigarettes and Other Tobacco Products and Progression to Daily Cigarette Smoking.

OBJECTIVES: To identify predictors of becoming a daily cigarette smoker over the course of 4 years. METHODS: We identified 12- to 24-year-olds at wave 1 of the US Population Assessment of Tobacco and Health Study and determined ever use, age at first use, and daily use through wave 4 for 12 tobacco products. RESULTS: Sixty-two percent of 12- to 24-year-olds (95% confidence interval [CI]: 60.1% to 63.2%) tried tobacco, and 30.2% (95% CI: 28.7% to 31.6%) tried ≥5 tobacco products by wave 4. At wave 4, 12% were daily tobacco users, of whom 70% were daily cigarette smokers (95% CI: 67.4% to 73.0%); daily cigarette smoking was 20.8% in 25- to 28-year-olds (95% CI: 18.9% to 22.9%), whereas daily electronic cigarette (e-cigarette) vaping was 3.3% (95% CI: 2.4% to 4.4%). Compared with single product triers, the risk of progressing to daily cigarette smoking was 15 percentage points higher (adjusted risk difference [aRD] 15%; 95% CI: 12% to 18%) among those who tried ≥5 products. In particular, e-cigarette use increased the risk of later daily cigarette smoking by threefold (3% vs 10%; aRD 7%; 95% CI: 6% to 9%). Daily smoking was 6 percentage points lower (aRD -6%; 95% CI: -8% to -4%) for those who experimented after age 18 years. CONCLUSIONS: Trying e-cigarettes and multiple other tobacco products before age 18 years is strongly associated with later daily cigarette smoking. The recent large increase in e-cigarette use will likely reverse the decline in cigarette smoking among US young adults.

Initial Views and Experiences of Vaping in Prisons: A Qualitative Study With People in Custody Preparing for the Imminent Implementation of Scotland's Prison Smokefree Policy.

INTRODUCTION: Scotland is one of the few countries in which e-cigarettes were available in prisons before the introduction of a comprehensive national smokefree policy, to assist in its implementation. This qualitative study explores the initial views and experiences of vaping in this specific context, from the perspective of people in custody (prisoners). AIMS AND METHODS: Twenty-eight people in custody were interviewed approximately 1-2 months after rechargeable e-cigarettes were made available in prisons and 2-5 weeks before implementation of a smokefree policy. Data were thematically analyzed to identify the range and diversity of views and experiences. RESULTS: Participants expressed support for e-cigarettes in preparation for the smokefree policy, describing their symbolic and practical value in this context. Uptake of vaping was strongly influenced by the need for participants to manage without tobacco in the near future. Participants evaluated their initial vaping experiences, either positively or negatively, in relation to the utility of e-cigarettes for mandated smoking abstinence and in providing satisfaction, pleasure, and novelty. Participant views on several issues related to e-cigarette use, both specific to the prison population (product choice and cost) and more generally (safety and long-term use), are explored. CONCLUSIONS: Our findings suggest possible benefits of e-cigarettes as one means of supporting smokefree policy in a population with many smokers. They also point to potential challenges posed by vaping in prisons and smokefree settings caring for similar populations. There is a need for ongoing measures to maximize the health benefits of smokefree settings and for further research on vaping in situations of enforced abstinence. IMPLICATIONS: To our knowledge, no published studies have explored views and experiences of vaping in prison, when rechargeable vapes were new and the removal of tobacco was imminent. The results can inform tobacco control policy choices, planning and implementation in prisons and similar settings. In prison systems that permitting vaping, it is important that other measures (eg, information campaigns and nicotine dependence services) are implemented concurrently to minimize potential risks to the health or personal finances of people in custody.

Profile of incidental exposures to e-cigarette liquids in Europe, 2018-2019.

BACKGROUND: Following the implementation of the European Union Tobacco Product Directive (EU TPD) regulations on e-cigarette products in 2016, we assessed the current profile of e-cigarette liquid exposure incidents and their associated health outcomes. METHODS: De-identified data were received from poison centers in eight EU Member States (Sweden, the Netherlands, Italy, Hungary Austria, Finland, Spain and Croatia) reporting on e-cigarette liquid exposure incidents between August 2018 to December 2019. Descriptive analysis was conducted to present incident characteristics and health outcomes. Chi-square tests and multivariable logistic regression analysis were used to test associations. RESULTS: Of the 223 e-liquid exposure incidents recorded by poison centers in multiple EU MS, 64.7% of the cases were unintentional exposures, ranging from 48.4% among adults aged ≥19 years to 100.0% among children aged 0-5 years (p < 0.05). The most frequent route of exposure was ingestion (73.5%) while55.2% experienced any clinical symptoms, including nausea (16.6%), vomiting (11.1%), and dizziness (9.0%). 57.8% of the cases were treated at the residence or on-site. CONCLUSION: Further monitoring is warranted, using uniform reporting requirements, to ensure the continued compliance to the EU TPD and assess its long-term impact on related incident characteristics.

Effects of vapourized THC and voluntary alcohol drinking during adolescence on cognition, reward, and anxiety-like behaviours in rats.

Cannabis and alcohol co-use is prevalent in adolescence, but the long-term behavioural effects of this co-use remain largely unexplored. The aim of this study is to investigate the effects of adolescent alcohol and Δ9-tetrahydracannabinol (THC) vapour co-exposure on cognitive- and reward-related behaviours. Male Sprague-Dawley rats received vapourized THC (10 mg vapourized THC/four adolescent rats) or vehicle every other day (from post-natal day (PND) 28-42) and had continuous voluntary access to ethanol (10% volume/volume) in adolescence. Alcohol intake was measured during the exposure period to assess the acute effects of THC on alcohol consumption. In adulthood (PND 56+), rats underwent behavioural testing. Adolescent rats showed higher alcohol preference, assessed using the two-bottle choice test, on days on which they were not exposed to THC vapour. In adulthood, rats that drank alcohol as adolescents exhibited short-term memory deficits and showed decreased alcohol preference; on the other hand, rats exposed to THC vapour showed learning impairments in the delay-discounting task. Vapourized THC, alcohol or their combination had no effect on anxiety-like behaviours in adulthood. Our results show that although adolescent THC exposure acutely affects alcohol drinking, adolescent alcohol and cannabis co-use may not produce long-term additive effects.

Characterization and Validation of the Second-generation wPUM Topography Monitors.

INTRODUCTION: Little is known about the natural use behavior of new and emerging tobacco products due to the limited availability of reliable puff topography monitors suitable for ambulatory deployment. An understanding of use behavior is needed to assess the health impact of emerging tobacco products and inform realistic standardized topography profiles for emissions studies. The purpose of this study is to validate four monitors: the wPUM cigalike, vapepen, hookah, and cigarette monitors. AIMS AND METHODS: Each wPUM monitor was characterized and validated for range, accuracy, and resolution for puff flow rate, duration, volume, and interpuff gap in a controlled laboratory environment. Monitor repeatability was assessed for each wPUM monitor using four separate week-long natural environment monitoring studies including cigalike, vapepen, hookah, and cigarette users. RESULTS: The valid flow rate range was 10 to 100 mL/s for cigalike and cigarette monitors, 10 to 95 mL/s for vapepen monitors, and 50 to 400 mL/s hookah monitors. Flow rate accuracy was within ±2 mL/s for cigalike, vapepen, and cigarette monitors and ±6 mL/s for the hookah monitor. Durations and interpuff gaps as small as 0.2 s were measured to within ±0.07 s. Monitor calibrations changed by 4.7% (vapepen), 1.5% (cigarette), 0.5% (cigalike), and 0.1% (hookah) after 1 week of natural environment use. CONCLUSIONS: The wPUM topography monitors were demonstrated to be reliable when deployed in the natural environment for a range of emerging tobacco products. IMPLICATIONS: The current study addresses the lack of available techniques to reliably monitor topography in the natural environment, across multiple emerging tobacco products. Natural environment topography data will inform standardized puffing protocols for premarket tobacco product applications. The ability to quantify topography over extended periods of time will lead to a better understanding of use behavior and better-informed regulations to protect public health.

Trends in youth e-cigarette and cigarette use between 2013 and 2019: insights from repeat cross-sectional data from the COMPASS study.

OBJECTIVES: E-cigarettes are an increasingly popular product among youth in Canada. However, there is a lack of long-term data presenting trends in use. As such, the objective of this study was to examine trends in e-cigarette and cigarette use across various demographic characteristics between 2013 and 2019 among a large sample of secondary school youth in Canada. METHODS: Using repeat cross-sectional data from a non-probability sample of students in grades 9 to 12, this study explored trends in the prevalence of ever and current e-cigarette use and cigarette smoking between 2013-2014 and 2018-2019 in British Columbia, Alberta, Ontario, and Quebec. Trends in ever and current e-cigarette use and cigarette smoking were studied across demographic variables among students in Ontario. RESULTS: The prevalence of e-cigarette ever and current use was variable across province and increased over time, particularly between 2016-2017 and 2018-2019. In contrast, the prevalence of current cigarette smoking was relatively stable over the study period, decreasing significantly in Alberta and Ontario between 2017-2018 and 2018-2019. In Ontario, the prevalence of ever and current e-cigarette use increased among all grades, both genders, and all ethnicities. CONCLUSION: Consistent with data from the United States, the prevalence of e-cigarette use among our large sample of Canadian youth has increased substantially in a short period of time. Surveillance systems should continue to monitor the prevalence of tobacco use among youth. Additional interventions may be necessary to curb e-cigarette use among Canadian youth.

RéSUMé: OBJECTIFS: Les cigarettes électroniques sont de plus en plus populaires auprès des jeunes au Canada. Il manque cependant de données à long terme sur les tendances de leur usage. C'est pourquoi nous avons cherché à examiner les tendances de l'usage des cigarettes électroniques et des cigarettes selon diverses caractéristiques démographiques entre 2013 et 2019 dans un vaste échantillon de jeunes fréquentant l'école secondaire au Canada. MéTHODE: À l'aide de données transversales répétées d'un échantillon non probabiliste d'élèves de la 9e à la 12e année, l'étude a exploré les tendances de la prévalence de l'usage antérieur et actuel des cigarettes électroniques et des cigarettes entre 2013-2014 et 2018-2019 en Colombie-Britannique, en Alberta, en Ontario et au Québec. Les tendances de l'usage antérieur et actuel des cigarettes électroniques et des cigarettes ont été étudiées pour diverses variables démographiques chez les élèves de l'Ontario. RéSULTATS: La prévalence de l'usage antérieur et actuel des cigarettes électroniques varie selon la province et a augmenté avec le temps, particulièrement entre 2016-2017 et 2018-2019. Par contre, la prévalence de l'usage actuel des cigarettes a été relativement stable sur la période de l'étude et a sensiblement diminué en Alberta et en Ontario entre 2017-2018 et 2018-2019. En Ontario, la prévalence de l'usage antérieur et actuel des cigarettes électroniques a augmenté chez les élèves de toutes les années, des deux sexes et de toutes les origines ethniques. CONCLUSION: Comme pour les données des États-Unis, la prévalence de l'usage des cigarettes électroniques dans notre vaste échantillon de jeunes Canadiens a considérablement augmenté sur une courte période. Les systèmes de surveillance devraient continuer à surveiller la prévalence du tabagisme chez les jeunes. Des interventions supplémentaires pourraient être nécessaires pour freiner l'usage des cigarettes électroniques chez les jeunes Canadiens.

Vaping-Related Mobile Apps Available in the Google Play Store After the Apple Ban: Content Review.

BACKGROUND: In response to health concerns about vaping devices (eg, youth nicotine use, lung injury), Apple removed 181 previously approved vaping-related apps from the App Store in November 2019. This policy change may lessen youth exposure to content that glamorizes vaping; however, it may also block important sources of information and vaping device control for adults seeking to use vaping devices safely. OBJECTIVE: Understanding the types of nicotine and cannabis vaping-related apps still available in the competing Google Play Store can shed light on how digital apps may reflect information available to consumers. METHODS: In December 2019, we searched the Google Play Store for vaping-related apps using the keywords "vape" and "vaping" and reviewed the first 100 apps presented in the results. We reviewed app titles, descriptions, screenshots, and metadata to categorize the intended substance (nicotine or cannabis/tetrahydrocannabinol) and the app's purpose. The most installed apps in each purpose category were downloaded and evaluated for quality and usability with the Mobile App Rating Scale. RESULTS: Of the first 100 apps, 79 were related to vaping. Of these 79 apps, 43 (54%) were specific to nicotine, 3 (4%) were specific to cannabis, 1 (1%) was intended for either, and for the remaining 31 (39%), the intended substance was unclear. The most common purposes of the apps were making do-it-yourself e-liquids (28/79, 35%) or coils (25/79, 32%), games/entertainment (19/79, 24%), social networking (16/79, 20%), and shopping for vaping products (15/79, 19%). Of the 79 apps, at least 4 apps (5%) paired with vaping devices to control temperature or dose settings, 8 apps (10%) claimed to help people quit smoking using vaping, and 2 apps (3%) had the goal of helping people quit vaping. CONCLUSIONS: The majority of vaping-related apps in the Google Play Store had features either to help users continue vaping, such as information for modifying devices, or to maintain interest in vaping. Few apps were for controlling device settings or assisting with quitting smoking or vaping. Assuming that these Google Play Store apps were similar in content to the Apple App Store apps that were removed, it appears that Apple's ban would have a minimal effect on people who vape with the intention of quitting smoking or who are seeking information about safer vaping via mobile apps.

Use of electronic cigarettes and secondhand exposure to their aerosols are associated with asthma symptoms among adolescents: a cross-sectional study.

BACKGROUND: Globally, a surge in electronic cigarette (e-cigarette) use has been observed in recent years, with youth being the most susceptible group. Given their recent emergence, studies assessing the health consequences of using e-cigarettes and exposure to their secondhand aerosols (SHA) are limited. Hence, this study sought to assess associations between e-cigarette use and household exposure to SHA from e-cigarettes with asthma symptoms among adolescents. METHODS: A school-based cross-sectional study was conducted by enrolling high school students (n = 1565; aged 16-19 years) in Kuwait. Participants self-completed a questionnaire on tobacco products use (e-cigarettes and cigarettes) and asthma symptoms. Current e-cigarette use and cigarette smoking were defined as any use in the past 30 days. Household exposure to SHA from e-cigarettes in the past 7 days was reported as none (0 days), infrequent (1-2 days), and frequent (≥ 3 days). Asthma symptoms included current (past 12 months) wheeze, current asthma (history of clinical diagnosis and current wheeze and/or medication use), and current symptoms of uncontrolled asthma (≥ 4 attacks of wheeze, ≥ 1 night per week sleep disturbance from wheeze, and/or wheeze affecting speech). Associations were assessed using Poisson regression with robust variance estimation, and adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) were estimated. RESULTS: Among the analytical study sample (n = 1345), current e-cigarette use and cigarette smoking was reported by 369 (27.4%) and 358 (26.6%) participants, respectively. Compared to never e-cigarette users and never cigarette smokers, current e-cigarette users with no history of cigarette smoking had increased prevalence of current wheeze (aPR = 1.54, 95% CI 1.01-2.45) and current asthma (aPR = 1.85, 95% CI 1.03-3.41). Moreover, the frequency of exposure to household SHA from e-cigarettes was associated with asthma symptoms. For example, compared to those with no exposure to household SHA, frequent exposure to household SHA was associated with current wheeze (aPR = 1.30, 95% CI 1.04-1.59), current asthma (aPR = 1.56, 95% CI 1.13-2.16), and current uncontrolled asthma symptoms (aPR = 1.88, 95% CI 1.35-2.62). CONCLUSIONS: E-cigarette use and their household SHA exposure were independently associated with asthma symptoms among adolescents. Hence, such observations indicate that e-cigarette use and passive exposure to their aerosols negatively impact respiratory health among adolescents.

Association of Electronic Cigarette Use With Incident Respiratory Conditions Among US Adults From 2013 to 2018.

Importance: Generating robust and timely evidence about the respiratory health risks of electronic cigarettes (e-cigarettes) is critical for informing state and federal regulatory standards for product safety. Objective: To examine the association of e-cigarette use with incident respiratory conditions, including chronic obstructive pulmonary disease (COPD), emphysema, chronic bronchitis, and asthma. Design, Setting, and Participants: This prospective cohort study used data from the nationally representative cohort of US adults from the Population Assessment of Tobacco and Health (PATH) study, including wave 1 from 2013 to 2014, wave 2 from 2014 to 2015, wave 3 from 2015 to 2016, and wave 4 from 2016 to 2018. Individuals aged 18 years and older at baseline with no prevalent respiratory conditions were included in the analyses. Analyses were conducted from February to July 2020. Exposures: e-Cigarette use was assessed by self-reported current use status (never, former, or current) at baseline. Main Outcomes and Measures: Incident respiratory conditions, including COPD, emphysema, chronic bronchitis, and asthma, as well as a composite respiratory disease encompassing all 4 conditions. Results: Among 21 618 respondents included in the analyses, 11 017 (491%) were men and 12 969 (65.2%) were non-Hispanic White. A total of 14 213 respondents were never e-cigarette users, 5076 respondents (11.6%) were former e-cigarette users, and 2329 respondents (5.2%) were current e-cigarette users. Adjusted for cigarette and other combustible tobacco product use, demographic characteristics, and chronic health conditions, there was an increased risk of respiratory disease among former e-cigarette uses (incidence rate ratio [IRR], 1.28; 95% CI, 1.09-1.50) and current e-cigarette users (IRR, 1.31; 95% CI, 1.08-1.59). Among respondents with good self-rated health, the IRR for former e-cigarette users was 1.21 (95%CI, 1.00-1.46) and the IRR for current e-cigarette users was 1.43 (95% CI, 1.14-1.79). For specific respiratory diseases among current e-cigarette users, the IRR was 1.33 (95% CI, 1.06-1.67) for chronic bronchitis, 1.69 (95% CI, 1.15-2.49) for emphysema, 1.57 (95% CI, 1.15-2.13) for COPD, and 1.31 (95% CI, 1.01-1.71) for asthma. Conclusions and Relevance: This cohort study found that e-cigarette use was associated with an increased risk of developing respiratory disease independent of cigarette smoking. These findings add important evidence on the risk profile of novel tobacco products.