Systematic review of biomarker findings from clinical studies of electronic cigarettes and heated tobacco products

Contingent Effects of E-Cigarette Warning Label Messages on Cognitive Elaboration and Fear Among U.S. Youth Ages 14-17 by Vaping Experience and Peer Vaping Behavior

The U.S. Food and Drug Administration (FDA) currently requires a warning about the addictive nature of nicotine to be placed on electronic cigarette advertisements and packaging. To consider the value of additional warning messages on public health outcomes, this study examines the additive effect of new warnings that are based on recent claims from U.S. federal authorities. We conducted a secondary analysis of recent data from 1,202 U.S. youth ages 14-17 to test the impact of exposure to additional warnings placed on advertisements for vaping products on cognitive elaboration, fear, and willingness to vape and smoke. This investigation also looked closely at effects on youth who may have increased risk of future vaping due to prior vaping experiences or having friends who vape. Exposure to the alternative warnings did not amplify cognitive elaboration compared to the current FDA warning alone, but it did increase fear. Youth elaboration on both the benefits and risks of vaping was associated with willingness to both vape and smoke, but fear was not associated with either outcome. The effects of warning label exposure and cognitive elaboration varied by prior vaping experience and having at least one friend who vapes. We conclude by discussing the implications of this contingent pattern of effect and association.

Lung lipids associated with smoking and ECIG use in a cross-sectional study and clinical trial

BACKGROUND

While electronic cigarettes (ECIG) may have lower toxicant delivery than cigarettes, ECIG-liquids and aerosols still contain toxicants that can potentially disrupt lung lipid homeostasis.

METHODS

Participants from two studies underwent bronchoscopy and bronchoalveolar lavage (BAL). Ninety-eight participants (21-44 years old) were included in a cross-sectional study, with 17 ECIG users, 52 non-smokers, and 29 smokers. In the four-week clinical trial, 30 non-smokers were randomly assigned to use nicotine-free, flavorless ECIG or no use. A panel of 75 quantifiable lipid species and 7 lipid classes were assessed in the BAL using two tandem mass spectrometry (MS/MS) platforms. Ten cytokines and lipid-laden macrophages (LLM) were analyzed using the V-PLEX Plus Proinflam Combo 10 panel and Oil Red O staining, respectively.

RESULTS

In the cross-sectional study, 43 lipids were associated with smoking status at FDR<0.1, including two between ECIG and non-smokers (PC(14:0/18:1) and PC(18:0/14:0)) in pairwise follow-up analyses (Bonferroni-adjusted p<0.017). Associations between lipid species and cotinine, inflammatory markers, including IL-1β and IL-8, and LLM were also identified, as well as differences in lipid classes between smokers and the other groups. Smokers had higher saturated lipids, including ceramide (CER), sphingomyelin (SM), and diacylglycerol (DAG) than that of non-smokers and ECIG users. No significant associations were identified in the 4-week clinical trial.

CONCLUSIONS

Smoking was associated with altered lipid levels, as compared to both non-smokers and ECIG users; the majority were downregulated and ECIG effects tend to be smaller in magnitude than smoking effects, although some were different than those in the smokers group. This is a novel study of healthy individuals examining lipidomic differences between smokers, ECIG users, and non-smokers, indicating potential roles of smoking and ECIG-related lipid alterations in pulmonary disease.

TRIAL REGISTRATION

The study was approved by The OSU Institutional Review Board (OSU-2015C0088) in accordance with its ethical standards, the Helsinki declaration, and the Belmont Report, and is registered on Clinicaltrials.gov (NCT02596685; 2015-11-04).

Electronic cigarette use, related health outcomes and policy interventions in the USA: a call for research to fill evidence gaps

The population-level health consequences of electronic cigarette (e-cigarette) use are heavily debated. This special communication provides updated evidence and identifies knowledge gaps across domains including: (1) health-related outcomes associated with e-cigarette use; (2) initiation and use of e-cigarettes among youth and young adults; (3) concurrent use of electronic and combustible cigarettes; (4) transitions from combustible cigarette use to exclusive e-cigarette use among adults who currently smoke cigarettes and (5) existing e-cigarette-related policy interventions. Literature was searched through PubMed and Medline for systematic reviews, scoping reviews, meta-analyses and primary research articles including emerging topics not covered in reviews published between 1 January 2017 and 1 January 2024. E-cigarette use is associated with several adverse acute health outcomes; there is currently insufficient longitudinal evidence to predict chronic health outcomes. Prevalence of e-cigarette use among youth is considerable and may be associated with subsequent combustible cigarette smoking. Evidence for the health and behavioural impact of dual use of e-cigarettes and combustible cigarettes is limited by imprecise measurement of exposure. Evidence on adults completely substituting combustible cigarettes for e-cigarettes is strong in clinical trials; observational studies do not show complete substitution. Finally, the effects of e-cigarette-related policy interventions to restrict e-cigarette consumption are currently limited in scope and too short-lived to draw causal inferences. Substantial evidence gaps related to the use, associated health impacts and regulation of e-cigarettes in the USA are identified, and we suggest key areas for future research to address that are crucial for informing the public health approach to e-cigarettes.

Impact of heated tobacco products on biomarkers of potential harm and adverse events: a systematic review and meta-analysis

OBJECTIVE

To systematically review available data on the effects of heated tobacco products (HTPs) on biomarkers of potential harm (BoPH) and adverse events, including comparison to cigarettes, e-cigarettes and smoking abstinence.

DATA SOURCES

Web of Science, Scopus, MedRxiv, ClinicalTrials.gov, ICTRP database and HTP manufacturer libraries were searched from January 2010 to December 2024.

STUDY SELECTION

Included studies were interventional clinical trials of any design that measured BoPH or adverse events in adults assigned a marketed HTP and another assigned either cigarettes, e-cigarettes or smoking abstinence.

DATA EXTRACTION

Two reviewers independently extracted data into a predesigned form and assessed risk of bias using Cochrane's Risk of Bias tool version 1.

DATA SYNTHESIS

BoPH data were synthesised using effect direction plots. A random-effects model was used to calculate pooled risk ratios for adverse event data. 40 studies (10 independent, 29 industry-affiliated and 1 of unclear affiliation) were included. Only nine studies lasted longer than 5 days. 19 involved using the intervention just once. Risk of bias was high for 32 studies and unclear for 8. Data on 143 BoPH indicated short-term HTP use had mixed effects compared with cigarettes, e-cigarettes and smoking abstinence. The rate of adverse event reporting was not significantly different between HTP and any comparator group.

CONCLUSIONS

Despite a growing evidence base, significant limitations hinder interpretation of the data, which do not yet provide clear indication of harm or benefit, even compared with cigarettes. Longer, better quality studies independent of tobacco industry funding are needed to determine the health impacts of HTPs.

Impact of Heating Conventional Cigarettes With a Novel Device on Health-Related Biomarkers and Cigarette Use Patterns Among Chinese Adult Smokers Unwilling to Quit: A Pilot Randomized Controlled Trial

INTRODUCTION

We evaluated the impact of heating conventional cigarettes with a novel heated tobacco product (HTP) device on biomarkers and cigarette use patterns in Chinese adult smokers unwilling to quit smoking.

AIMS AND METHODS

In this pilot randomized controlled trial, 50 eligible participants were allocated to either control group (smoking conventional cigarettes) or HTP device group (switching to using heated conventional cigarettes by the HTP device). Participants in the HTP device group went through a 2-day run-in period and then used heated conventional cigarettes exclusively for 5 days, followed by flexible use for 14 days. Five biomarkers of exposure (BoEs) were measured at baseline and on day 7. Thirteen biomarkers of biological effect (BoBEs) were measured at baseline and on day 21. Safety, daily cigarette consumption, craving, withdrawal symptoms, and device acceptability, were assessed.

RESULTS

BoE levels decreased by 26.4 % to 71.4% from baseline in the HTP device group, while BoBE levels did not significantly change in either group. In the HTP group, 56% exclusively used heated conventional cigarettes during the flexible use period, experiencing reduced cravings and withdrawal symptoms, while dual users consumed more cigarettes. Mild to moderate device-related reactions were reported in 36% of users. Satisfaction, taste, and harm reduction belief scores averaged 7.4, 6.6, and 8.7 (out of 10), respectively.

CONCLUSIONS

Switching to heated conventional cigarettes with the HTP device may reduce short-term exposure to smoke toxicants. However, it can lead to increased tobacco use among dual users. Further investigation is needed to confirm these preliminary findings.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (http://www.chictr.org.cn/), ChiCTR2200065055, October 26, 2022.

IMPLICATIONS

This study is the first to evaluate the impact of heating conventional cigarettes with a novel HTP device on health-related biomarkers and cigarette use patterns among Chinese adult smokers. This novel HTP device can directly heat conventional cigarettes without the necessity for specifically designed tobacco products, avoiding the potential additive risks of traditional HTPs. If the results of this study could be further verified by randomized controlled clinical trials with larger sample sizes, this novel HTP device could serve as a short-term harm reduction alternative for smokers unwilling to quit.

Estimating lung cancer risk from e-cigarettes and heated tobacco products: applications of a tool based on biomarkers of exposure and of potential harm

BACKGROUND

Reliable epidemiological data are limited on the lung cancer risk of groups using e-cigarettes (ECIGs) and groups using heated tobacco products (HTPs).

AIM

We describe a methodology to estimate the lung cancer risk of these groups according to their levels of biomarkers of exposure (BOEs) and of potential harm (BOPHs).

METHODS

Using 28 search terms for BOEs and 82 for BOPHs we sought publications reporting biomarker-specific data from North America and Europe comparing individuals who smoke cigarettes and individuals who use other established products (ETPs; cigars, pipes, smokeless tobacco (ST) and/or snuff/snus). Publications were selected using defined inclusion/exclusion criteria. Additionally using lung cancer relative risk (RR) estimates for users of specific ETPs derived from recent meta-analyses of epidemiological studies in these regions, we derived a regression model predicting the lung cancer RR by level of each specific biomarker. Separately for groups using ECIGs and using HTPs the lung cancer risk was then estimated by combining RR estimates for selected biomarkers. Our primary estimates only considered biomarkers statistically significantly (p < 0.01) related to lung cancer risk which showed no significant (p < 0.01) misfit to the RR of 1.0 for non-users-those with no use of ETPs, ECIGs or HTPs.

RESULTS

Based on 38 available publications, we extracted biomarker-specific data for ETPs for 56 BOEs within 21 of the 28 search terms considered and for 54 BOPHs within 29 of the 82. The regression slope fitted to the lung cancer risk was significant (p < 0.01) for 22 BOEs and six BOPHs. However, the predicted RR for non-users significantly (p < 0.01) differed from 1.0 for 16 of these biomarkers. We estimated the lung cancer RR for using ECIGs, derived from 30 estimates for 10 biomarkers, as 1.88 (95% CI 1.60-2.22), the excess risk (ER = RR - 1) being 6.8% of that for smokers of cigarettes. The RR estimate varied little in most sensitivity analyses conducted, but increased markedly after removing the restriction to significant model fit. We estimated the lung cancer RR for using HTPs, combining estimates for four BOEs, as 1.44 (0.41-5.08), the ER being 3.4% of that for smokers of cigarettes.

CONCLUSIONS

Despite some methodological limitations, our approach estimates risk when reliable epidemiological data are unavailable. Using the biomarkers considered here, the model indicates that the lung cancer risk for individuals using ECIGs is much lower than for smokers of cigarettes, and suggests that the risk for those using HTPs is also low. Research using additional data could add precision to these findings.

Harm perceptions across vaping product features: An on-line cross-sectional survey of adults who smoke and/or vape in the United Kingdom

BACKGROUND AND AIMS

Vaping products are diverse with a wide variety of features, and popular products change rapidly. This study examined the features and types of vaping products that people who smoke and/or vape perceive contribute to the health harms of vaping.

DESIGN, SETTING AND PARTICIPANTS

This was a cross-sectional survey co-designed with adults who smoked/vaped and pre-registered. An on-line survey (November 2022) was used of a convenience sample of adults in the United Kingdom who smoked and/or vaped (n = 494).

MEASUREMENTS

As primary outcomes, respondents were asked to select any of 15 vaping product features they perceived might have any effect on the health harms of vaping (for each: selected, not selected). Independent variables were smoking/vaping status (smoke and vape; vape, formerly smoked; vape, never regularly smoked; smoke, do not currently vape); relative vaping harm perceptions [less harmful than smoking (accurate), equally/more harmful than smoking or do not know/refused (other)]. Binary logistic regressions were used to compare outcomes by current vaping/smoking status and relative harm perceptions, adjusting for age and sex.

FINDINGS

Most people (54.7%) selected between one and three features. The most frequently selected were nicotine concentration (62.2%) and amount of e-liquid consumed (59.1%), followed by nicotine type (e.g. salt or freebase; 33.0%), source/purchase location (25.3%), flavours (24.7%), temperature to heat e-liquid (21.1%), heat produced by device (20.9%), e-liquid brand (20.9%), amount of emissions (18.6%), device type (e.g. disposable, pod, tank; 17.2%), material of tank (17.0%), power/wattage (13.0%), device brand (8.1%), device size (4.1%) and device weight (2.4%). Higher nicotine concentrations, more e-liquid and salt (versus freebase) nicotine were perceived to confer greater harms. Disposables were perceived as slightly more harmful than reusable devices. There were few differences by current vaping/smoking status and between those with accurate (versus other) harm perceptions of vaping relative to smoking (P > 0.05 for most contrasts, adjusting for age and sex).

CONCLUSIONS

Certain features and types of vaping products [higher nicotine concentrations, more e-liquid consumed and salt (versus freebase) nicotine] were perceived to confer greater health harms among a sample of UK adults who smoked and/or vaped. Findings are consistent with pervasive misperceptions that nicotine is a major cause of harm, although e-liquid volume is likely to contribute to harms.

Randomized experimental test of a reduced-exposure message for an e-cigarette: comprehension and related misperceptions

Completely switching from cigarette smoking to electronic nicotine delivery systems (ENDS) reduces exposure to toxic substances. Yet, many smokers believe that ENDS are at least as harmful as smoking, making them less likely to switch from cigarettes to ENDS. Effectively communicating reduced-exposure information is critical, but such messages must be properly understood. This online study evaluated comprehension of a factual message, indicating that smokers who switch completely away from smoking to JUUL-brand ENDS can reduce their exposure to harmful chemicals in cigarette smoke. Participants were 12 557 adults 18+ years (smokers, dual users and former and never users of tobacco) randomized to see the reduced-exposure message or to a Control condition. After exposure to the message, the majority of smokers (89%) understood the need to switch completely from cigarettes to JUUL to achieve reduced exposure. Most smokers and nonusers (>75%) did not misperceive JUUL as completely eliminating exposure to harmful chemicals, and >85% understood that using JUUL has risk. Exposure to the message improved understanding of the intended audience for JUUL. Individuals with limited health literacy showed modestly lower comprehension, regardless of condition. Ensuring adequate comprehension of messages about reduced exposure from ENDS is important to ensuring that such messaging can benefit public health.

Biomarkers of Exposure to Nicotine and Selected Toxicants in Individuals Who Use Alternative Tobacco Products Sold in Japan and Canada from 2018 to 2019

BACKGROUND

Comparisons of nicotine and toxicant exposures between people who use different alternative tobacco products remain underexplored.

METHODS

This cross-sectional, multicountry study analyzed urinary metabolites of nicotine, tobacco-specific nitrosamines [4-methylnitrosamino-1-3-pyridyl-1-butanone (NNK)], and volatile organic compounds (acrolein, acrylamide, and acrylonitrile) among established users (n = 550) in Japan and Canada. Participants exclusively or concurrently used nicotine vaping products (NVP; Canada only), heated tobacco products (HTP; Japan only), and combustible cigarettes (CC; Japan and Canada) or abstained (Japan and Canada).

RESULTS

All product groups showed substantial nicotine exposure. Both HTPs and NVPs exposed exclusive users to lower toxicant levels than exclusive CC use. Canadian participants who exclusively used NVPs exhibited lower NNK and acrolein exposure but higher acrylamide exposure than Japanese participants who exclusively used HTPs. Concurrent use of CCs alongside alternative products exposed users to higher toxicant levels compared with exclusive use of either alternative product.

CONCLUSIONS

Exclusive use of alternative tobacco products results in significant nicotine exposure but substantially lower toxicant exposure compared with exclusive CC use. People who use HTPs in Japan may experience higher exposure to nicotine and certain toxicants (NNK and acrolein) than people who use NVPs in Canada. Concurrent use results suggest that partially substituting CCs with alternative products may reduce toxicant exposure but to a lesser extent than completely transitioning to alternative products.

IMPACT

Exposure patterns between two popular alternative tobacco products differ. The overall toxicant exposure from these products is lower than from CCs, providing critical data for regulatory decisions and public health considerations.

Changes in exposure to tobacco-related harmful and potentially harmful constituents among adults who switched completely from smoking cigarettes to use of the JUUL2 system for six days

INTRODUCTION

Adults who switch from smoking cigarettes to use of electronic nicotine delivery systems (ENDS) may reduce their exposure to harmful and potentially harmful constituents (HPHCs). This study assessed changes in exposure to HPHCs, assessed via biomarkers of exposure (BOEs), among adults who switched to a new ENDS product.

METHODS

Adults who smoke cigarettes (N = 89) were randomized to: (1) switch completely to using JUUL2 Virginia Tobacco (N = 24) or Polar Menthol (N = 24); (2) continue smoking usual brand (UB) cigarettes (N = 21); or (3) abstain from all tobacco/nicotine products (N = 20) for 6 d. Changes in exposure to nicotine and 11 other HPHCs from Baseline to Day 6 were compared among study groups.

RESULTS

Changes in nicotine exposure did not significantly differ between JUUL2 and UB Cigarette groups (ps > 0.37). Among participants who switched completely to JUUL2 products, median percent reductions (Day 6-Baseline) in non-nicotine BOEs ranged from 65% to 94%, significantly greater than changes in the UB Cigarette group (ps < 0.001). None of the non-nicotine BOEs significantly differed between the JUUL2 groups and the Abstinence group (ps > 0.025).

CONCLUSIONS

This randomized study demonstrates that adults who switch completely from smoking cigarettes to use of JUUL2 ENDS products substantially reduce their exposure to HPHCs associated with smoking-related diseases.

INTERNATIONAL STANDARD REGISTERED CLINICAL TRIAL NUMBER

ISRCTN27662176.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices that produce an aerosol by heating an e-liquid. People who smoke, healthcare providers, and regulators want to know if ECs can help people quit smoking, and if they are safe to use for this purpose. This is a review update conducted as part of a living systematic review.

OBJECTIVES

To examine the safety, tolerability, and effectiveness of using EC to help people who smoke tobacco achieve long-term smoking abstinence, in comparison to non-nicotine EC, other smoking cessation treatments, and no treatment.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 February 2024 and the Cochrane Tobacco Addiction Group's Specialized Register to 1 February 2023, reference-checked, and contacted study authors.

SELECTION CRITERIA

We included trials randomizing people who smoke to an EC or control condition. We included uncontrolled intervention studies in which all participants received an EC intervention. Studies had to report an eligible outcome.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. We used the risk of bias tool (RoB 1) and GRADE to assess the certainty of evidence. Critical outcomes were abstinence from smoking after at least six months, adverse events (AEs), and serious adverse events (SAEs). Important outcomes were biomarkers, toxicants/carcinogens, and longer-term EC use. We used a fixed-effect Mantel-Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in pairwise and network meta-analyses (NMA).

MAIN RESULTS

We included 90 completed studies (two new to this update), representing 29,044 participants, of which 49 were randomized controlled trials (RCTs). Of the included studies, we rated 10 (all but one contributing to our main comparisons) at low risk of bias overall, 61 at high risk overall (including all non-randomized studies), and the remainder at unclear risk. Nicotine EC results in increased quit rates compared to nicotine replacement therapy (NRT) (high-certainty evidence) (RR 1.59, 95% CI 1.30 to 1.93; I2 = 0%; 7 studies, 2544 participants). In absolute terms, this might translate to an additional four quitters per 100 (95% CI 2 to 6 more). The rate of occurrence of AEs is probably similar between groups (moderate-certainty evidence (limited by imprecision)) (RR 1.03, 95% CI 0.91 to 1.17; I2 = 0%; 5 studies, 2052 participants). SAEs were rare, and there is insufficient evidence to determine whether rates differ between groups due to very serious imprecision (RR 1.20, 95% CI 0.90 to 1.60; I2 = 32%; 6 studies, 2761 participants; low-certainty evidence). Nicotine EC probably results in increased quit rates compared to non-nicotine EC (moderate-certainty evidence, limited by imprecision) (RR 1.46, 95% CI 1.09 to 1.96; I2 = 4%; 6 studies, 1613 participants). In absolute terms, this might lead to an additional three quitters per 100 (95% CI 1 to 7 more). There is probably little to no difference in the rate of AEs between these groups (moderate-certainty evidence) (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 5 studies, 840 participants). There is insufficient evidence to determine whether rates of SAEs differ between groups, due to very serious imprecision (RR 1.00, 95% CI 0.56 to 1.79; I2 = 0%; 9 studies, 1412 participants; low-certainty evidence). Compared to behavioural support only/no support, quit rates may be higher for participants randomized to nicotine EC (low-certainty evidence due to issues with risk of bias) (RR 1.96, 95% CI 1.66 to 2.32; I2 = 0%; 11 studies, 6819 participants). In absolute terms, this represents an additional four quitters per 100 (95% CI 3 to 5 more). There was some evidence that (non-serious) AEs may be more common in people randomized to nicotine EC (RR 1.18, 95% CI 1.10 to 1.27; I2 = 6%; low-certainty evidence; 6 studies, 2351 participants) and, again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 0.93, 95% CI 0.68 to 1.28; I2 = 0%; 12 studies, 4561 participants; very low-certainty evidence). Results from the NMA were consistent with those from pairwise meta-analyses for all critical outcomes. There was inconsistency in the AE network, which was explained by a single outlying study contributing the only direct evidence for one of the nodes. Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued EC use. Very few studies reported data on other outcomes or comparisons; hence, evidence for these is limited, with CIs often encompassing both clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that ECs with nicotine increase quit rates compared to NRT and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care or no treatment also suggests benefit, but is less certain due to risk of bias inherent in the study design. Confidence intervals were, for the most part, wide for data on AEs, SAEs, and other safety markers, with no evidence for a difference in AEs between nicotine and non-nicotine ECs nor between nicotine ECs and NRT, but low-certainty evidence for increased AEs compared with behavioural support/no support. Overall incidence of SAEs was low across all study arms. We did not detect evidence of serious harm from nicotine EC, but longer, larger studies are needed to fully evaluate EC safety. Our included studies tested regulated nicotine-containing EC; illicit products and/or products containing other active substances (e.g. tetrahydrocannabinol (THC)) may have different harm profiles. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up-to-date information to decision-makers, this is a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Electronic Cigarette and Heated Tobacco Product Use and Their Association With Tobacco Control Factors Among Adults in Indonesia, Kazakhstan, and the Philippines

INTRODUCTION

Data on e-cigarette (EC) and heated tobacco product (HTP) use and the reasons for their use are useful for policy making. We report comparable nationally representative estimates of EC and HTP use and their associated factors.

AIMS AND METHODS

Global Adult Tobacco Survey data from Indonesia (2021), Kazakhstan (2019), and the Philippines (2021) were analyzed. The weighted prevalence rates and 95% CI of EC and HTP awareness, current use, and ever use, and their distribution by cigarette smoking status were calculated. Binary logistic regression analyses assessed socioeconomic, and tobacco control factors associated with EC and HTP use.

RESULTS

The prevalence (%) of EC awareness, ever use and current use were 48.7-69.4, 3.6-8.8, and 1.9-3.0, respectively. The prevalence(%) of HTP awareness, ever use and current use were 2.7-21.7, 0.2-2.1, and 0.1-1.2, respectively. The main reasons for EC and HTP use were attractive flavors(45.8%-73.9%), less harmful than smoking(23.0%-70.1%), and enjoyment(40.8%-76.7%). Avoiding going back to smoking(0.9%-54.4%) and quitting smoking(19.4%-49.8%) were less frequently cited reasons (except in the Philippines). EC/HTP use was associated with younger age, higher education and wealth, current/past smoking, exposure to information about the dangers of tobacco use, and advertisements about tobacco products and smoke-free rules at home.

CONCLUSIONS

The prevalence of EC and HTP use was higher among younger men with higher education and wealth, and current/past smoking. EC and HTP use should be closely monitored. Regulations to restrict the widespread marketing and sales of EC and HTP are needed to prevent the escalation of their use.

IMPLICATIONS

The population-level data provide the benchmark for future monitoring use of e-cigarettes and HTPs and identify population subgroups for future surveillance in low- and middle-income countries. The association of EC/HTP use with tobacco control-related factors provides leads for policies that should be formulated and implemented to regulate the product contents, marketing, and sales of EC and HTP.

Harm reduction associated with heated tobacco products: A systematic review and meta-analysis

Objective

We conducted a systematic review and meta-analysis of randomised studies in humans comparing the outcomes of switching to heated tobacco products (HTPs) versus continuing conventional tobacco smoking by burning.

Methods

We searched the electronic databases which included PubMed, Web of Science, Cochrane Controlled Trials Register, and Google Scholar from inception to May 2023. Randomised Controlled Trials (RCTs) in humans comparing HTPs with conventional burnt tobacco products were selected. Our search yielded 4817 search results, of which six RCTs (number of participants 1362, all from high-income countries) were selected. Five of the six included RCTs had low risk in four of five domains of bias; only one study had a high risk of bias in one domain. PRISMA guidelines were followed.

Results

There were 40 biomarkers of harm reduction reported categorised into six categories. One cancer biomarker (nitrosamine) and two cardiovascular biomarkers (eosinophils and total bilirubin) showed statistically significant harm reduction (total NNAL SMD=0·82, 95% CI 0·67-0·98, eosinophils SMD=0·38, 95% CI 0·12-0·65, total bilirubin SMD=0·71, 95% CI 0·28-1·31). The remaining biomarkers of harm in cardiovascular, inflammatory, metabolic, pulmonary, and renal categories showed imprecise findings.

Conclusions

In RCTs of moderate quality, some biomarkers show harm reduction associated with switching from burnt tobacco smoking to HTPs. The majority of the findings are imprecise due to the small sample sizes of the included studies. Sufficiently powered, robust RCTs targeting key harm reduction biomarkers within both upper and low-middle income country settings are required in the future.

Oral health risks in adults who use electronic nicotine delivery systems and oral nicotine pouches: a critical review of the literature and qualitative synthesis of the available evidence

BACKGROUND

Use of combustible cigarettes (CCs) and smokeless oral tobacco products are well documented risk factors for a variety of oral diseases. However, the potential oral health risks of using recently introduced (since about 2000) non-combustible tobacco/nicotine products (NCPs: electronic cigarettes (ECs), heated tobacco products (HTPs) and oral nicotine pouches (ONPs), remain poorly established.

METHODS

This review evaluates published human studies on detrimental oral health effects in people who use NCPs compared to those smoking cigarettes and those not using any tobacco/nicotine product (NU). We identified 52 studies, predominantly focusing on adults who used electronic cigarettes as an NCP. The studies exhibited significant heterogeneity regarding design, populations, endpoints and quality. Reported outcomes, based on both single and grouped endpoints were qualitatively evaluated by comparing people who use NCPs with NU and with people smoking CCs. Significant increases (indicating a worsening in oral health), significant decreases (indicating a lower level of detrimental effects) and no significant difference between groups were assigned scores of + 1, -1 and 0, respectively. Scores from studies belonging to the same single or grouped endpoints were averaged to a summary score ranging from - 1 to + 1.

RESULTS

The qualitative meta-analysis revealed that comparisons of EC versus NU groups yielded mean scores of 0.29 for pre-cancerous lesions (N = 14 observations), 0.27 for inflammatory processes (N = 83), 0.43 for oral clinical parameters (N = 93) and 0.70 for shifts in the oral microbiome (N = 10). The corresponding values for the EC versus CC group comparisons amounted to -0.33 (N = 15), -0.14 (N = 76), -0.27 (N = 78) and 0.57 (N = 7). Most studies had significant limitations regarding group sizes, duration of NCP use (mostly only a few years) and validity of self-reported exclusive NCP use. Notably, the implications of dual use (EC + CC) and prior CC use were often not adequately considered.

CONCLUSIONS

The evaluated studies suggest that use of ECs is associated with relatively fewer detrimental oral health effects compared to smoking, yet oral health status remains poorer compared to not using any tobacco/nicotine products. These results have to be interpreted with caution due to a number of limitations and uncertainties in the underlying studies, particularly the potential biases and confounding factors inherent in cross-sectional study designs.

The price elasticity of heated tobacco and cigarette demand: Empirical evaluation across countries

The market for heated tobacco products (HTPs) has grown rapidly in recent years, and many governments have started to include HTPs in tax codes to regulate their use. Currently, the evidence on how HTP prices impact tobacco use behaviors or whether consumers consider them as economic substitutes for cigarettes is lacking. This study is the first to answer these questions with a unique database to assess the own- and cross- price elasticities of HTP and cigarette demand. We collect a unique database of quarterly retail prices and sales of heated tobacco units and comparable scale cigarettes from 2014 to 2022, available for most countries where both HTPs and cigarettes are sold, and estimate the own- and cross- price elasticities of cigarette and HTP demand using a seemingly unrelated regression model. We find that HTP demand is price elastic (i.e., sensitive to prices) and has an own-price elasticity of -1.2 to -1.3, about four times greater than the own-price elasticity of cigarettes, which is about -0.3. We also find that cigarettes and HTPs are weak economic substitutes: while HTP demand is responsive to higher cigarette prices, cigarette demand is not sensitive to HTP prices. Our results suggest that tax policies that increase HTP and cigarette prices simultaneously will reduce HTP consumption without increasing cigarette consumption.

The relationship between insecure attachment and nicotine dependence among users of classic cigarettes, e-cigarettes, and heated tobacco products: a moderated mediation model

BACKGROUND

Previous research has investigated the association between attachment styles and smoking behaviors, indicating a positive association of insecure attachment styles with nicotine dependence. However, these links were mostly explored in adolescent and student samples. Moreover, the explanatory mechanisms and the variables influencing the strength of this relationship remained understudied. In this context, the present study aims to: (1) examine the associations between attachment anxiety, avoidance, and nicotine dependence; (2) investigate the mediating role of emotion dysregulation and metacognitions about smoking; and (3) test the moderating roles of psychological capital and type of tobacco product used by the participants.

METHOD

This cross-sectional study was conducted on a convenience sample of 447 participants who reported smoking. The age range of participants was 18 to 64 (M = 26.76; 59.7% women). All participants have completed five questionnaires measuring nicotine dependence, adult attachment, emotion dysregulation, metacognitions about smoking, and psychological capital. They also reported the type of tobacco product commonly used: classic cigarettes, e-cigarettes, or heated tobacco products.

RESULTS

Our findings show that the direct link between insecure attachment and nicotine dependence is rather inconsistent. However, it was mediated by the metacognitions about smoking. Psychological capital can act as a protective factor against the effects of attachment on nicotine dependence, especially for those using alternative tobacco products alongside classic cigarettes.

CONCLUSIONS

The findings highlight the possibility of developing better-tailored interventions and treatments to discourage smoking and increase smoking cessation. These should focus on eliminating the dysfunctional beliefs related to the metacognitions about smoking and on improving the levels of psychological capital. In addition, targeting attachment insecurities in early adolescence can also function as a mean to prevent smoking.

Urinary anatalline and nicotelline cut-points to distinguish between exclusive and dual use of tobacco products

OBJECTIVE

This study measured anatalline and nicotelline, two minor tobacco alkaloids, to discriminate between exclusive smokeless tobacco (SLT) use, exclusive electronic nicotine delivery systems (ENDS) use, exclusive cigarette use, dual SLT and cigarette use, and dual ENDS and cigarette use.

METHODS

N = 664 urine samples from participants in the Population Assessment of Tobacco and Health Study were analyzed for anatalline and nicotelline. Geometric means and 95% confidence intervals were calculated for biomarker levels and their ratios. Non-parametric Receiver Operating Characteristic analyses were used to determine optimal cut-points of natural log-transformed biomarker ratios for distinguishing between tobacco use groups.

RESULTS

The anatalline/nicotelline ratio distinguished exclusive cigarette from exclusive SLT use (threshold = 18.1, sensitivity = 89.3%, specificity = 86.4%, AUC = 0.90), and exclusive SLT from exclusive ENDS use (threshold = 12.8, sensitivity = 96.4%, specificity = 76.3%, AUC = 0.90) very well, but had reduced sensitivity and specificity when distinguishing exclusive cigarette from exclusive ENDS or any dual use with cigarettes.

CONCLUSIONS

This research fills a gap in understanding the public health consequences of SLT and ENDS use by providing objective measures that can signal use of these products alone or in combination with cigarettes.

The Smoky Impact of Nicotinic Acetylcholine Receptors on Testicular Function

Smoking habits (from classic cigarettes to e-cigarettes and heated tobacco) are a relatively common finding in the medical histories of couples referred to fertility centers. Tobacco smoke and e-cigarettes may deliver many substances with known harmful effects on both general and reproductive health, including nicotine. Nicotinic Acetylcholine receptors (nAChRs) form a heterogeneous family of ion channels that are differently expressed in different tissues. According to the homomeric or heteromeric combination of at least five different subunits (named from α to ε), they have peculiar pharmacological and biophysical properties. nAChRs respond to the neurotransmitter acetylcholine, which influences a number of physiological functions not restricted to neurons and plays an important role in the structure and function of non-neuronal tissues such as the testis. nAChRs are also the target of Nicotine, the active element responsible for tobacco addiction. This review summarizes recent findings on the involvement of nAChRs in testicular physiology, highlighting the effects of nicotine exposure observed in animal studies and clinical settings. We will discuss the latest data on fertility outcomes and the implications for understanding nAChR functions in reproductive health.

"I've lost my children to vaping": A frame analysis of the Australian media's construction of the "Youth vaping crisis"

BACKGROUND

Youth vaping has become an issue of extreme concern in the Australian public and political discourse, recently culminating in the announcement of further restrictions on the sale and use of nicotine vaping products (NVPs) by the Federal Government. We examine how youth vaping has been framed in the Australian news media in the six months leading up to the announcement of these new measures in May 2023.

METHODS

Drawing a sample from the Factiva database, we conducted a frame analysis on articles published during this six month period, identifying media framings that included the necessary components of a distinct Problem Definition, Causal Attribution, Moral Evaluation, and Treatment Recommendation.

RESULTS

We identified 123 relevant articles, and four dominant framings being applied. Most common was that of A Failure of Control, followed by A Poisonous Epidemic, A Health Behaviour Needing Regulation, and A Moral Failure.

CONCLUSION

These findings are discussed in the context of moral panic theory and how framings are constructed by the media in collaboration with policy actors to support particular policy measures.

Impact of switching from cigarette smoking to tobacco heating system use on biomarkers of potential harm in a randomized trial

BACKGROUND

Smoking cessation reduces the risk of developing smoking-related diseases. Although smoking prevalence has declined, many continue smoking cigarettes. Switching completely to smoke-free alternatives like the Tobacco Heating System (THS) 2.2-a heated tobacco product for which there is evidence demonstrating significantly reduced formation and exposure to harmful chemicals compared to cigarettes-has the potential to reduce the harm caused by continuing to smoke cigarettes.

METHODS

We conducted a 6-month clinical study (NCT02396381) with a 6-month extension (NCT02649556), initially randomizing 984 adult smokers to continue smoking or switch to THS (non-mentholated), of which 672 continued into the extension study. Endpoints were evaluated at baseline and at 3, 6, and 12 months. We longitudinally assessed biomarkers of potential harm (BoPHs) known to be reversible upon smoking cessation as indicators of pathways involved in the pathogenesis of cardiovascular or respiratory diseases and carcinogenicity. The need to cough and safety profile were also assessed. Impact on eight key BoPHs was used as a proxy to evaluate harm reduction potential.

RESULTS

At 12 months, comparison of BoPH levels between the predominant THS use and cigarette smoking groups showed a positive effect in favor of switching, partially or in full, to THS.

CONCLUSION

These results provide additional evidence of the harm reduction potential of THS for smokers who would otherwise continue smoking, but they need to be verified in long-term confirmatory studies.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT0264955. Date of registration: January 7, 2016 https://clinicaltrials.gov/ct2/show/NCT02649556.

A Scoping Review of Behavioural Studies on Heated Tobacco Products

Heated tobacco products (HTPs) are electronic devices that heat tobacco sticks to temperatures much lower than those which cause pyrolysis and combustion in cigarettes. While this electrical heating causes the formation of an inhalable aerosol which contains nicotine, the aerosol from HTPs contains significantly fewer and lower levels of the harmful and potentially harmful chemicals found in cigarette smoke. As a result, HTP use potentially conveys reduced risks to health compared to cigarette smoking. While this relative reduction in individual health risk is becoming clearer, what is less certain is the impact of HTPs on overall population‑level health, taking into account both the potential positive impact on adult smokers who completely switch to using HTPs and any unintended impacts such as use by tobacco non‑users and particularly by youth. The aim of this scoping review was to collate and evaluate the published scientific evidence to date, with a cut‑off of 1 January 2024, investigating the impact of HTPs on population‑level health. This evaluation suggests that HTP use is almost exclusively observed among those with a history of cigarette smoking, and there is a growing body of evidence for the ability of HTPs to provide support for adult smokers to transition away from cigarette smoking, in the absence of any significant "gateway" into tobacco use initiation. Many studies have reported a significant degree of dual use of cigarettes and HTPs, and efforts to assess the reasons for such patterns of use, whether these provide overall exposure reductions, and whether dual use acts as a bridge towards a complete transition away from cigarette smoking, requires further investigation. In addition, correction of the widespread and increasing misperceptions of HTPs among adult smokers is recommended to promote HTP uptake as a potentially less harmful alternative to smoking in this population.

Tobacco Smoking or Nicotine Phenotype and Severity of Clinical Presentation at the Emergency Department (SMOPHED): Protocol for a Noninterventional Observational Study

BACKGROUND

In the last few years, several nicotine products have become available as alternatives to smoking tobacco. While laboratory and limited clinical studies suggest that these devices are less toxic compared to classic tobacco cigarettes, very little is known about their epidemiological impact. Visiting the emergency department (ED) often represents the first or even the only contact of patients with the health care system. Therefore, a study conducted at the ED to assess the impact of these products on health can be reliable and reflect a real-life setting.

OBJECTIVE

The aim of this noninterventional observational study (SMOPHED study) is to analyze the association between the severity of clinical presentation observed during ED visits among patients using various nicotine products and the subsequent outcomes, specifically hospitalization and mortality.

METHODS

Outcomes (hospitalization and mortality in the ED) will be examined in relation to various patterns of nicotine products use. We plan to enroll approximately 2000 participants during triage at the ED. These individuals will be characterized based on their patterns of tobacco and nicotine consumption, identified through a specific questionnaire. This categorization will allow for a detailed analysis of how different usage patterns of nicotine products correlate with the clinical diagnosis made during the ED visits and the consequent outcomes.

RESULTS

Enrollment into the study started in March 2024. We enrolled a total of 901 participants in 1 month (approximately 300 potential participants did not provide the informed consent to participate). The data will be analyzed by a statistician as soon as the database is completed. Full data will be published by December 2024.

CONCLUSIONS

There is substantial debate about the harm reduction potential of alternative nicotine products in terms of their smoking-cessation and risk-reduction potential. This study represents an opportunity to document epidemiological data on the link between the use of different types of nicotine products and disease diagnosis and severity during an ED visit, and thus evaluate the harm reduction potential claims for these products.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/54041.

Effect of conventional cigarettes and e-cigarettes on salivary biomarkers: A systematic review

Background

E-cigarette consumption is increasing, and like conventional smoking, it can cause some harmful effects. This systematic review compared the effect of conventional cigarettes and e-cigarettes on salivary biomarkers.

Methods

The search strategies included electronic databases (Medline/PubMed, Scopus, EMBASE) and related journals up to May 2023. A qualitative assessment was performed on data extracted from the included studies. Seven studies were included in this systematic review (number of patients=563).

Results

Eleven biomarkers were assessed and compared between e-cigarette and conventional cigarette smokers. The data showed that the different effects of electronic and conventional cigarettes on the level of these biomarkers were not achievable. Due to the heterogeneity of the studies (I2 statistic>90%), performing a meta-analysis was impossible. Even after a sub-group classification, homogeneous data were not achieved.

Conclusion

The current data do not provide evidence of obtainable outcomes between conventional cigarettes and e-cigarettes on salivary biomarkers.

Comparison of Publications on Heated Tobacco Products With Conventional Cigarettes and Implied Desirability of the Products According to Tobacco Industry Affiliation: A Systematic Review

INTRODUCTION

Heated tobacco products (HTPs) have been advertised as "reduced-harm" tobacco products compared to conventional cigarettes (CC); however, no direct evidence supporting HTPs being desirable for human health exists. A previous systematic review reported that evidence on HTPs published in 2017 or earlier was primarily drawn from industry-related papers. We aimed to investigate whether tobacco industry-affiliated studies are more likely to conclude that HTPs are more desirable than CC.

METHODS

PubMed and Ichushi-Web were searched up to March 15, 2022, for studies on HTPs published in 2017 or after. We selected studies that assessed any measures of HTPs and CC, including secondary analyses using gray literature in English or Japanese. We excluded review articles except for a meta-analysis that met the aforementioned criteria. Data on the authors' affiliations, grant, conflict of interest, category of research subjects, and interpretation were extracted. Research members in two groups independently assessed the papers; discrepancies were solved by discussion between the groups.

RESULTS

Overall, 134 studies met the criteria. Eighty-seven (64.9%) of them were affiliated with the tobacco industry. Of the 134 studies, 56.3% (49/87) of the industry-affiliated studies versus 19.1% (9/47) of nonindustry-affiliated studies concluded that HTPs were more desirable than CC (p < .01). No study investigated clinically relevant outcomes, such as disease occurrence.

CONCLUSIONS

Publications on HTPs in the biomedical literature from January 2017 to March 2022 were dominated by tobacco industry-affiliated studies. More than half of them concluded that HTPs were more desirable than CC compared to independent studies.

IMPLICATIONS

Tobacco industry advertises HTPs as "reduced-harm" tobacco products compared to CC. HTP users tend to consider HTPs as alternative tobacco products less harmful than CC (ie, products for "harm reduction"). Our results demonstrated that papers written by tobacco industry-affiliated authors concluded that HTPs were more desirable than CC compared to papers by independent authors. However, all their judgments were based on surrogate outcomes. Surrogate outcomes are not necessarily linked to clinically relevant outcomes such as disease occurrence. Further studies on HTPs using clinically relevant outcomes are warranted by independent authors from tobacco industry.

Critical appraisal of interventional clinical trials assessing heated tobacco products: a systematic review

OBJECTIVE

To critically assess the methodological characteristics and quality of interventional clinical trials investigating the effects of heated tobacco products (HTPs).

DATA SOURCES

Web of Science (Core collection and MEDLINE), Scopus, MedRxiv, ClinicalTrials.gov and ICTRP trial databases and transnational HTP manufacturer online publication libraries were searched for clinical trials on HTPs published between January 2010 and April 2022.

STUDY SELECTION

Interventional clinical trials of any design, in which at least one group of adult participants used a currently marketed HTP, were selected by two reviewers with good or very good agreement.

DATA EXTRACTION

Data relating to trial characteristics and effects of intervention on primary outcomes were extracted using a predesigned form. Risk of bias was assessed using Cochrane's Risk of Bias tool v1.

DATA SYNTHESIS

40 trials were included, 29 of which were tobacco industry affiliated. Methodological characteristics, such as registration, design, setting, comparator interventions, participants, outcomes and analyses, varied between trials, though there were few significant differences between industry-affiliated and independent trials. Of the 40 trials, 33 were judged to be at high risk of bias and 6 at unclear risk of bias. Trial findings were not significantly associated with either affiliation or risk of bias.

CONCLUSIONS

The conduct and reporting of HTP interventional clinical trials were poor in many respects and limited to investigating effects of short-term exposure. These trials fall short of what is needed to determine whether HTPs are beneficial to public health, meaning they may not be a sound basis for tobacco control policy decisions.

Comparative evaluation of ten blood biomarkers of inflammation in regular heated tobacco users and non-smoking healthy males-a pilot study

Heated tobacco products (HTPs) are novel tobacco products that are alternatives to cigarettes. The study aimed to investigate the effect of HTPs on blood biomarkers of inflammation as well as to provide a comparative evaluation between daily heated tobacco users and healthy men who do not use nicotine products. This case-control study was carried out among 92 healthy males in Poland (Lodz-Province) aged 20-56 years: 44 daily heated tobacco users (daily use in the past 90 days) and 48 controls who do not use nicotine products. The history of use of the nicotine-containing products was self-reported and verified using a saliva cotinine test. A 20 ml blood sample was collected and the levels of ten blood biomarkers were analyzed. Among all heated tobacco users (n = 44), only the levels of interleukin 8 (IL-8) were significantly higher when compared to controls: 6.86 vs. 3.95 (p = 0.01). Among exclusive heated tobacco users (n = 33), the levels of IL-8 were also significantly higher when compared to controls: 7.76 vs. 3.95 (p = 0.01). IL-8 level was positively correlated (r = 0.37; p = 0.01) with the daily number of heated tobacco sticks. Out of 10 different biomarkers of inflammation, only IL-8 levels were significantly elevated in heated tobacco use compared to controls.

Comparing Adult Smokers Who Switched to JUUL versus Continuing Smokers: Biomarkers of Exposure and of Potential Harm and Respiratory Symptoms

OBJECTIVES

Real-world evidence on exposure to harmful and potentially harmful constituents (HPHCs) and on biological effects in cigarette smokers who switch to electronic nicotine delivery systems (ENDS) can inform the health effects of switching.

AIMS AND METHODS

This cross-sectional, observational study assessed adults who had smoked ≥10 cigarettes/day for ≥10 years, comparing 124 continuing cigarette smokers (Smokers) to 140 former smokers who switched to JUUL-brand ENDS exclusively for ≥6 months (Switchers). Assessments included biomarkers of exposure (BOEs) to select HPHCs, biomarkers of potential harm (BOPHs) related to smoking-related diseases, psychometric assessments of dependence on cigarettes and ENDS, respectively, and respiratory symptoms. Planned analyses compared geometric means, adjusted for demographic covariates; further analyses adjusted for additional lifestyle and smoking history covariates.

RESULTS

Nicotine levels were significantly higher in Switchers (median time switched = 3 years), who were unusually heavy users of JUUL. All other BOEs, including NNAL and HPMA3 (primary endpoints), were significantly lower in Switchers than Smokers. Most BOPHs (sICAM-1 [primary], and eg, white blood cell count, MCP1, HbA1c) were significantly lower in Switchers than Smokers; HDL was significantly higher. Switchers reported significantly lower dependence on JUUL than Smokers did on cigarettes, and respiratory symptom scores were significantly lower among Switchers than Smokers.

CONCLUSIONS

Compared to continuing smokers, smokers who switched to JUUL had substantially lower exposures to multiple HPHCs, favorable differences in markers of inflammation, endothelial function, oxidative stress, and cardiovascular risk, and fewer respiratory symptoms. These findings suggest that switching from cigarettes to JUUL likely reduces smokers' health risks.

IMPLICATIONS

Short-term confinement studies and randomized clinical trials demonstrate that adult smokers who switch completely to ENDS experience substantial reductions in exposure to many smoking-related toxicants. This study extends those findings to longer periods of switching to JUUL-brand ENDS (almost 3 years on average) under naturalistic use conditions in real-world settings and also found that switching to JUUL resulted in favorable differences in BOPHs more proximally related to smoking-induced disease, as well as in respiratory symptoms. Smokers who switch to ENDS reduce their exposure to toxicants, likely reducing their disease risk.

Exposure to Tobacco-Specific Nitrosamines Among People Who Vape, Smoke, or do Neither: A Systematic Review and Meta-Analysis

INTRODUCTION

Smoking exposes people to high levels of Tobacco-Specific Nitrosamines (TSNAs), which include potent carcinogens. We systematically reviewed TSNA exposure between people smoking, vaping, and doing neither.

AIMS AND METHODS

Databases were searched between August 2017-March 2022, using vaping-related terms. Peer-reviewed articles reporting TSNA metabolites (NNAL, NNN, NAB, and NAT) levels in bio-samples among adults exclusively vaping, exclusively smoking, or doing neither were included. Where possible, meta-analyses were conducted.

RESULTS

Of 12 781 identified studies, 22 were included. TSNA levels fell substantially when people who smoke switched to vaping in longitudinal studies and were lower among people who vaped compared to smoked in cross-sectional studies. Levels of TSNAs were similar when comparing people who switched from smoking to vaping, to those who switched to no use of nicotine products, in longitudinal studies. Levels were higher among people who vaped compared to people who neither vaped nor smoked in cross-sectional studies.When comparing people who vaped to smoked: pooled urinary NNAL was 79% lower across three randomized controlled trials and 96% lower across three cross-sectional studies; pooled NAB was 87% lower and NAT 94% lower in two cross-sectional studies. When comparing people who neither vaped nor smoked to people who vaped, pooled urinary NNAL was 80%, NAB 26%, and NAT 27% lower in two cross-sectional studies. Other longitudinal data, and NNN levels could not be pooled.

CONCLUSIONS

Exposure to all TSNAs was lower among people who vaped compared to people who smoked. Levels were higher among people who vaped compared to people who neither vaped nor smoked.

IMPLICATIONS

As well as TSNAs, there are many other toxicant exposures from smoking and vaping that can increase the risk of disease. However, it is likely that the reduced exposure to TSNAs from vaping relative to smoking reduces the risk to health of those who use vaping products to quit smoking. Future high-quality research, with robust definitions of exclusive vaping and smoking, and accounting for TSNAs half-lives, is needed to fully assess exposure to TSNAs among people who vape.

Adult smokers' Complete Switching Away from Cigarettes at 6, 9, and 12 Months after Initially Purchasing a JUUL e-Cigarette

Background: Electronic nicotine delivery systems (ENDS) have the potential to benefit public health if smokers completely switch from cigarettes to ENDS. Methods: A cohort of adult smokers (age ≥ 21) who purchased a JUUL Starter Kit was followed for 12 months after the initial purchase. We defined "switching" as past-30-day abstinence from smoking (even if JUUL use had stopped), and analyzed factors associated with achievement and maintenance of self-reported repeated point-prevalence switching (RPPS) at three follow-ups, i.e., no past-30-day smoking at months 6, 9, and 12. Results: RPPS was reported by 21.6% of the 12,537 evaluable smokers. Smokers with lighter smoking history and lower cigarette dependence at baseline were more likely to report RPPS. RPPS was also associated with daily use of JUUL (Month-3: OR = 2.32, 95% CI = 2.02-2.68; Month-6: OR = 1.73, 95% CI = 1.42-2.10), and with greater subjective reinforcing effects from JUUL use (assessed by the mCEQ, Month-3: OR = 1.46, 95% CI = 1.38-1.56; Month-6: OR = 1.11; 95% CI = 1.02-1.20). Even among smokers who did not meet the criteria of RPPS (i.e., who smoked at least once), 35.5% reported past 30-day point-prevalence switching on at least one follow-up, and their cigarette consumption was substantially reduced compared to baseline. Conclusions: Approximately one-fifth of adult smokers reported 30-day point-prevalence abstinence at 6, 9, and 12 months after purchasing JUUL. Greater use of JUUL and stronger subjective reinforcing effects were associated with nonsmoking, validating the potential for ENDS to substitute for smoking, with potential for positive impacts on individual and population health.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol by heating an e-liquid. People who smoke, healthcare providers and regulators want to know if ECs can help people quit smoking, and if they are safe to use for this purpose. This is a review update conducted as part of a living systematic review.

OBJECTIVES

To examine the safety, tolerability and effectiveness of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term smoking abstinence, in comparison to non-nicotine EC, other smoking cessation treatments and no treatment.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register to 1 February 2023, and Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 July 2023, and reference-checked and contacted study authors.

SELECTION CRITERIA

We included trials in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention as these studies have the potential to provide further information on harms and longer-term use. Studies had to report an eligible outcome.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Critical outcomes were abstinence from smoking after at least six months, adverse events (AEs), and serious adverse events (SAEs). We used a fixed-effect Mantel-Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in pairwise and network meta-analyses (NMA).

MAIN RESULTS

We included 88 completed studies (10 new to this update), representing 27,235 participants, of which 47 were randomized controlled trials (RCTs). Of the included studies, we rated ten (all but one contributing to our main comparisons) at low risk of bias overall, 58 at high risk overall (including all non-randomized studies), and the remainder at unclear risk. There is high certainty that nicotine EC increases quit rates compared to nicotine replacement therapy (NRT) (RR 1.59, 95% CI 1.29 to 1.93; I2 = 0%; 7 studies, 2544 participants). In absolute terms, this might translate to an additional four quitters per 100 (95% CI 2 to 6 more). There is moderate-certainty evidence (limited by imprecision) that the rate of occurrence of AEs is similar between groups (RR 1.03, 95% CI 0.91 to 1.17; I2 = 0%; 5 studies, 2052 participants). SAEs were rare, and there is insufficient evidence to determine whether rates differ between groups due to very serious imprecision (RR 1.20, 95% CI 0.90 to 1.60; I2 = 32%; 6 studies, 2761 participants; low-certainty evidence). There is moderate-certainty evidence, limited by imprecision, that nicotine EC increases quit rates compared to non-nicotine EC (RR 1.46, 95% CI 1.09 to 1.96; I2 = 4%; 6 studies, 1613 participants). In absolute terms, this might lead to an additional three quitters per 100 (95% CI 1 to 7 more). There is moderate-certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 5 studies, 1840 participants). There is insufficient evidence to determine whether rates of SAEs differ between groups, due to very serious imprecision (RR 1.00, 95% CI 0.56 to 1.79; I2 = 0%; 9 studies, 1412 participants; low-certainty evidence). Due to issues with risk of bias, there is low-certainty evidence that, compared to behavioural support only/no support, quit rates may be higher for participants randomized to nicotine EC (RR 1.88, 95% CI 1.56 to 2.25; I2 = 0%; 9 studies, 5024 participants). In absolute terms, this represents an additional four quitters per 100 (95% CI 2 to 5 more). There was some evidence that (non-serious) AEs may be more common in people randomized to nicotine EC (RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low-certainty evidence; 4 studies, 765 participants) and, again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 0.89, 95% CI 0.59 to 1.34; I2 = 23%; 10 studies, 3263 participants; very low-certainty evidence). Results from the NMA were consistent with those from pairwise meta-analyses for all critical outcomes, and there was no indication of inconsistency within the networks. Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued EC use. Very few studies reported data on other outcomes or comparisons, hence, evidence for these is limited, with CIs often encompassing both clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that ECs with nicotine increase quit rates compared to NRT and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain due to risk of bias inherent in the study design. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, with no difference in AEs between nicotine and non-nicotine ECs nor between nicotine ECs and NRT. Overall incidence of SAEs was low across all study arms. We did not detect evidence of serious harm from nicotine EC, but the longest follow-up was two years and the number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates. Further RCTs are underway. To ensure the review continues to provide up-to-date information to decision-makers, this review is a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Development and validation of a method for preparing heated tobacco product aerosol condensate (HTPAC) for large-scale toxicity data acquisition

A method of preparing heated tobacco product aerosol condensate (HTPAC) was developed to expedite HTP toxicity evaluation, and the effectiveness was assessed. To prepare HTPAC, HTP aerosol was generated and collected using a Cambridge filter (particulate phase) and Dulbecco's phosphate buffered saline (DPBS; gaseous phase). The aerosol collected on the Cambridge filter was extracted using methanol, which was thereafter removed by nitrogen purging. The HTP aerosol residue was mixed with DPBS loaded with the collected HTP vapor, ultimately yielding HTPAC. Nicotine and formaldehyde, key harmful compounds in HTP aerosol, were detected in HTPAC (901 ± 224 and 22.2 ± 3.90 µg stick-1, respectively, comparable to those in HTP aerosol (990-1350 (nicotine) and 2.33-21.9 µg stick-1 (formaldehyde)). Propylene glycol and vegetable glycerin, which influence the amount of HTP aerosol, were detected at similar levels in HTPAC and HTP aerosol (propylene glycol = 616 ± 57.1 (HTPAC) and 320-630 µg stick-1 (aerosol) and vegetable glycerin = 2418 ± 224 (HTPAC) and 1667-4000 µg stick-1 (aerosol)). Known components of HTP aerosol (hydroxyacetone, acetic acid, triacetin, and 2-furanmethanol) were also detected in HTPAC. Consequently, HTPAC offers an effective method for concentrating harmful compounds found in HTP aerosols. This, in turn, facilitates comprehensive toxicity assessments, paving the way for guidelines ensuring the safe utilization of HTP.

Do alternative tobacco products induce less adverse respiratory risk than cigarettes?

RATIONALE

Due to the relatively short existence of alternative tobacco products, gaps exist in our current understanding of their long-term respiratory health effects. We therefore undertook the first-ever side-by-side comparison of the impact of chronic inhalation of aerosols emitted from electronic cigarettes (EC) and heated tobacco products (HTP), and combustible cigarettes (CC) smoke.

OBJECTIVES

To evaluate the potential differential effects of alternative tobacco products on lung inflammatory responses and efficacy of vaccination in comparison to CC.

METHODS

Mice were exposed to emissions from EC, HTP, CC, or air for 8 weeks. BAL and lung tissue were analyzed for markers of inflammation, lung damage, and oxidative stress. Another group was exposed for 12 weeks and vaccinated and challenged with a bacterial respiratory infection. Antibody titers in BAL and sera and pulmonary bacterial clearance were assessed.

MAIN RESULTS

EC- and HTP-aerosols significantly augmented lung immune cell infiltrates equivalent to that achieved following CC-exposure. HTP and CC significantly increased neutrophil numbers compared to EC. All products augmented numbers of B cells, T cells, and pro-inflammatory IL17A+ T cells in the lungs. Decreased lung antioxidant activity and lung epithelial and endothelial damage was induced by all products. EC and HTP differentially augmented inflammatory cytokines/chemokines in the BAL. Generation of immunity following vaccination was impaired by EC and HTP but to a lesser extent than CC, with a CC > HTP > EC hierarchy of suppression of pulmonary bacterial clearance.

CONCLUSIONS

HTP and EC-aerosols induced a proinflammatory pulmonary microenvironment, lung damage, and suppressed efficacy of vaccination.

Immunology in COPD and the use of combustible cigarettes and heated tobacco products

Chronic obstructive pulmonary disease (COPD) is one of the most common chronic respiratory diseases, characterised by high morbidity and mortality. COPD is characterised by a progressive decline of lung function caused by chronic inflammatory reactions in the lung tissue due to continual exposure to harmful molecules by inhalation. As prevention plays a very important role in COPD, quitting smoking is the most important factor in reducing the decline in lung function. Unfortunately, many people are unable to break their nicotine addiction. This paper summarises current knowledge about combustible cigarettes (CSs) and alternative tobacco products such as heated tobacco products (HTPs) in COPD. The paper focuses on the immunological aspects of COPD and the influence of tobacco products on lung tissue immunology. There are differences in research results between HTPs and CSs in favour of HTPs. More long-term studies are needed to look at the effects of HTPs, especially in COPD. However, there is no doubt that it would be best for patients to give up their nicotine addiction completely.

DNA damage in human oral cells induced by use of e-cigarettes

The use of electronic cigarettes (e-cigarettes) has increased rapidly in the United States, especially among high school students. e-Cigarettes contain some recognized carcinogens and may induce DNA damage in oral cells. The aim of this review is to summarize studies reporting DNA adducts or other types of DNA damage in oral cells in vitro or in vivo upon exposure to e-cigarette vapor and to evaluate the possible connections between e-cigarette exposure and oral cancer. Three databases including PubMed, Scopus, and EMBASE and gray literature were searched for articles published up to April 24, 2022. After screening 321 articles, we extracted 27 for further investigation. Based on the inclusion criteria, 22 articles were eligible for this review. The in vitro studies demonstrate that e-cigarette liquid or vapor can induce DNA damage, oxidative stress, DNA double-stranded breaks, apoptosis, cytotoxicity, and genotoxicity in different types of oral cells. The clinical studies showed that e-cigarette users have significantly higher levels of N'-nitrosonornicotine, acrolein DNA adducts, metanuclear anomalies, gene regulation, and lactate dehydrogenase enzyme expression and significantly lower levels of apurinic/apyrimidinic sites than non-users. Comparison of micronuclei levels between e-cigarette users and non-users gave inconsistent results. e-Cigarettes are implicated in DNA damage to oral cells, but publications to date present limited evidence. Future studies with larger sample sizes are required to investigate the long-term consequences of e-cigarette use.

Perceptions, intentions, and actual use of a consumer nicotine gum

BACKGROUND

Little is known about perceptions, use intentions, and behaviors of adults regarding nicotine gum that is marketed and regulated as a consumer product rather than as a medicinal nicotine replacement therapy (NRT).

METHODS

Survey data were collected from a Qualtrics online panel (N = 1000) of adults who had never used a consumer nicotine gum, recruited based on smoking behavior, and from current and former purchasers of one commercially available nicotine gum product (LUCY Chew and Park), recruited via emails to a customer database (N = 500). In addition to descriptive cross-sectional analyses, logistic regression was used to estimate the probability of intent to try and of product appeal among these different groups.

RESULTS

Among online panel respondents, individuals who smoked with and without plans to quit showed high intention to try the product (odds ratios 15.6 [95% CI 9.3, 27.6] and 9.8 [95% CI 5.8, 17.3] respectively, compared to people who formerly smoked) and persons who had never smoked showed low intentions to try. These results stood regardless of flavor. Among current and former purchasers of the study product, 43.4% of persons who had smoked cigarettes regularly indicated they were motivated to try the product "to help me quit smoking." Only 0.6% of young adult consumers of the nicotine gum (aged 21-30) had not tried tobacco products previously.

CONCLUSIONS

Consumer nicotine gum does not appear to attract those who have never used a tobacco product and the results for young adults suggest minimal appeal to youth. The study product was used primarily by individuals who currently smoke and/or use e-cigarettes but who wished to quit or reduce consumption. These results suggest that a consumer nicotine gum may reduce harm by substituting for higher-risk products such as combustible cigarettes.

Role of untargeted omics biomarkers of exposure and effect for tobacco research

Tobacco research remains a clear priority to improve individual and population health, and has recently become more complex with emerging combustible and noncombustible tobacco products. The use of omics methods in prevention and cessation studies are intended to identify new biomarkers for risk, compared risks related to other products and never use, and compliance for cessation and reinitation. to assess the relative effects of tobacco products to each other. They are important for the prediction of reinitiation of tobacco use and relapse prevention. In the research setting, both technical and clinical validation is required, which presents a number of complexities in the omics methodologies from biospecimen collection and sample preparation to data collection and analysis. When the results identify differences in omics features, networks or pathways, it is unclear if the results are toxic effects, a healthy response to a toxic exposure or neither. The use of surrogate biospecimens (e.g., urine, blood, sputum or nasal) may or may not reflect target organs such as the lung or bladder. This review describes the approaches for the use of omics in tobacco research and provides examples of prior studies, along with the strengths and limitations of the various methods. To date, there is little consistency in results, likely due to small number of studies, limitations in study size, the variability in the analytic platforms and bioinformatic pipelines, differences in biospecimen collection and/or human subject study design. Given the demonstrated value for the use of omics in clinical medicine, it is anticipated that the use in tobacco research will be similarly productive.

Use of Vaping as a Smoking Cessation Aid: A Review of Clinical Trials

Purpose

Smoking is a global public health concern, with a significant negative impact on human health and healthcare spending. Vaping, or the use of electronic cigarettes (e-cigarettes), has emerged as a popular alternative to traditional nicotine replacement therapies (NRTs) for smoking cessation. While considered less harmful than combustible cigarettes, the long-term health effects of e-cigarettes (vaping) are unknown. Therefore, this study aimed to identify and provide a comprehensive overview of the performance of vaping in clinical trials.

Patients and Methods

A search was conducted in the ClinicalTrials.gov database on April 14th, 2023, using the search term "smoking cessation, e-cigarettes, NRTs, and vaping". Inclusion and exclusion criteria were defined to identify relevant clinical trials. Randomized controlled trials (RCTs) and non-randomized clinical trials that evaluated vaping as a therapeutic approach to smoking cessation were included.

Results

A total of 87 clinical trials were identified, of which only seven were related to smoking cessation through vaping as a form of treatment. The primary endpoint was the effect of vaping as smoking cessation, and the secondary endpoints were patients' abstinence rate, withdrawal symptoms, and adverse events of e-cigarettes. Most of the trials used e-cigarettes as an intervention, with some trials including a combination of e-cigarettes and other NRTs. The trials lasted from 4 weeks to 12 months. The overall results of the trials indicated that vaping was effective in helping smokers to quit. It was also associated with a lower risk of adverse events than combustible cigarettes.

Conclusion

Vaping appears to be an effective method for smoking cessation, and it is associated with a lower risk of adverse events than combustible cigarettes.

The pass-through of excise taxes to market prices of heated tobacco products (HTPs) and cigarettes: a cross-country analysis

BACKGROUND AND OBJECTIVE

The market for heated tobacco products (HTPs) has grown markedly in recent years, and many governments have started to tax HTPs to regulate their use. To evaluate the impacts of HTP taxes on tobacco use behaviors and health consequences, we first need to assess if they effectively raise HTP prices in a tax system that also taxes cigarettes. This study jointly evaluates the pass-through of taxes to prices of HTPs and cigarettes.

DATA AND METHODS

We use a unique database on statutory HTP and cigarette taxes and retail prices of Marlboro-branded heated tobacco units and cigarettes from 2014 to 2021, developed by the Campaign for Tobacco Free Kids, in all countries where HTPs are sold. To estimate the pass-through of taxes to prices, we employ a seemingly unrelated regressions model. We also use an event study to test the impact of introducing HTPs to cigarette markets, as well as amending tax codes to include HTPs, on prices and price gaps.

CONCLUSIONS AND POLICY IMPLICATIONS

Currently, the debate over whether HTPs should be taxed in comparison with cigarettes considers their potential harm reduction impact, and most countries tax HTPs at much lower rates than cigarettes in order to keep HTP prices lower than cigarette prices. However, the direct pass-through rate of HTP taxes to prices is several times smaller than that of cigarettes, resulting in very similar unit prices of HTPs and cigarettes. Further, while cigarette taxes are over-shifted to cigarette prices, HTP taxes are under-shifted to HTP prices, suggesting that tax gaps between the two products does not translate to price gaps. The results overall suggest that the lower taxes on HTPs do not lead to lower prices as compared to cigarettes and are unlikely to incentivize cigarette smokers to transition to HTPS for lower costs. Under this scenario, taxing both products equivalently could be an option to raise additional tax revenue.

Comparison of biomarkers of exposure among US adult smokers, users of electronic nicotine delivery systems, dual users and nonusers, 2018-2019

The harm caused by cigarette smoking is overwhelmingly due to byproducts of tobacco combustion. Electronic Nicotine Delivery Systems (ENDS) provide nicotine to users without combustion, and may support tobacco harm reduction among cigarette smokers who would not otherwise quit in the near term. Analyses of Wave 5 of the Population Assessment of Tobacco and Health (PATH) Study compared biomarkers of exposure (BOE) levels for nicotine, 3 metals, 2 tobacco-specific nitrosamines and 14 smoking-related volatile organic compounds in 151 exclusive ENDS users, 1341 exclusive cigarette smokers, 115 dual users (cigarettes and ENDS), and 1846 past 30-day nonusers of tobacco, adjusting for demographics. Nicotine exposure in ENDS users and dual users did not significantly differ from smokers. Among ENDS users, 16 of 18 other BOEs were significantly lower than smokers'; 9 BOEs were not significantly different from nonusers. Among dual users smoking < 10 cigarettes/day, 15 of 18 non-nicotine BOEs were significantly lower than smokers', whereas in dual users smoking ≥ 10 cigarettes per day none of the BOEs significantly differed from smokers'. In this representative sample of US adults, exclusive use of ENDS (vs. cigarette smoking) was associated with much lower exposures to many harmful chemicals associated with smoking-related disease. BOE levels in dual users were directly related to their cigarette consumption. These BOE data provide further evidence that ENDS expose users to substantially lower levels of toxicants than combustible cigarettes, confirming their potential for harm reduction.

Heated Tobacco Products and Chronic Obstructive Pulmonary Disease: A Narrative Review of Peer-Reviewed Publications

An estimated 65 million people worldwide have moderate or severe chronic obstructive pulmonary disease (COPD), an umbrella term used to describe a group of progressive lung diseases that obstruct airflow such as emphysema and chronic bronchitis. Smoking contributes to an estimated 90% of COPD cases, as the harmful chemicals produced during tobacco combustion damage the lungs and airways. Although smoking cessation is the only intervention shown to improve COPD prognosis in smokers, many patients who try to quit continue to smoke. The continued use of conventional cigarettes exacerbates COPD symptoms, and globally more than 3 million people die from the disease every year. The last two decades have seen the introduction of combustion-free nicotine delivery alternatives that produce significantly lower levels of the harmful components in cigarette smoke, and researchers have begun to assess the impact of switching from cigarettes to these products. Several studies have examined how patients with COPD use e-cigarettes as assistance for quitting, but few have examined how heated tobacco products (HTP) may reduce risk. This narrative review summarises results from pre-clinical, clinical, and real-world evidence studies showing possible harm reduction benefits for patients with COPD who switch to HTPs rather than continuing to smoke cigarettes. Epidemiological studies, real-world data analyses, and randomised clinical trials must be conducted to determine whether switching from cigarettes to HTPs can improve health outcomes in patients with COPD who would otherwise continue to smoke combustible cigarettes.

Biomarkers of potential harm in people switching from smoking tobacco to exclusive e-cigarette use, dual use or abstinence: secondary analysis of Cochrane systematic review of trials of e-cigarettes for smoking cessation

AIMS

This study aims to compare biomarkers of potential harm between people switching from smoking combustible cigarettes (CC) completely to electronic cigarettes (EC), continuing to smoke CC, using both EC and CC (dual users) and using neither (abstainers), based on behaviour during EC intervention studies.

DESIGN

Secondary analysis following systematic review, incorporating inverse variance random-effects meta-analysis and effect direction plots.

SETTING

This study was conducted in Greece, Italy, Poland, the United Kingdom and the United States.

PARTICIPANTS

A total of 1299 adults smoking CC (nine studies) and provided EC.

MEASUREMENTS

Measurements were conducted using carbon monoxide (CO) and 26 other biomarkers.

FINDINGS

In pooled analyses, exhaled CO (eCO) was lower in EC versus EC + CC [mean difference (MD) = -4.40 parts per million (p.p.m.), 95% confidence interval (CI) = -12.04 to 3.24, two studies] and CC (MD = -9.57 p.p.m., 95% CI = -17.30 to -1.83, three studies). eCO was lower in dual users versus CC only (MD = -1.91 p.p.m., 95% CI = -3.38 to -0.45, two studies). Magnitude rather than direction of effect drove substantial statistical heterogeneity. Effect direction plots were used for other biomarkers. Comparing EC with CC, 12 of 13 biomarkers were significantly lower in EC users, with no difference for the 13th. Comparing EC with dual users, 12 of the 25 biomarkers were lower for EC, and five were lower for dual use. For the remaining eight measures, single studies did not detect statistically significant differences, or the multiple studies contributing to the outcome had inconsistent results. Only one study provided data comparing dual use with CC; of the 13 biomarkers measured, 12 were significantly lower in the dual use group, with no statistically significant difference detected for the 13th. Only one study provided data on abstainers.

CONCLUSIONS

Switching from smoking to vaping or dual use appears to reduce levels of biomarkers of potential harm significantly.

Multiple endpoint in vitro toxicity assessment of a prototype heated tobacco product indicates substantially reduced effects compared to those of combustible cigarette

This study aimed to compare the aerosol chemistry and in vitro toxicological profiles of two prototype Heated Tobacco Product (p-HTP) variants to the 1R6F Reference Cigarette. In the neutral red uptake screen the p-HTPs were 37-39-fold less potent than 1R6F, in the micronucleus assay, responses to the p-HTPs were 8-22-fold less, and in the Ames test mutagenicity was weak or removed compared to 1R6F. The cardiovascular scratch wound assay revealed 58-fold greater wound healing impairment following exposure to 1R6F smoke extracts than the p-HTPs. Furthermore, in seven cell stress-related high content screening endpoints (cell count, cytochrome c release, mitochondrial membrane potential, GSH depletion, NFkB translocation, phosphorylation of c-jun and phosphorylation of H2AX), at 4 and 24 h, responses were substantially greater to 1R6F smoke extracts at comparable nicotine levels. The reduced in vitro effects of the p-HTPs were attributed to substantial reductions (90-97%) in selected HPHCs measured compared to in 1R6F smoke. The multiple endpoint in vitro assessment approach provides greater mechanistic insight and the first reported toxicological characterisation of these p-HTPs in the literature. Overall, the findings contribute to the growing weight of evidence that HTPs may offer a reduced harm mode of nicotine delivery to adult smokers.

Heated Tobacco Products: Awareness, Beliefs, Use and Susceptibility among US Adult Current Tobacco Users, 2021

Limited data exist on the awareness, beliefs, and use of heated tobacco products (HTPs). Data from 1583 U.S. adult (age ≥ 21 years) current tobacco users were collected in 2021. Participants self-reported HTP awareness, beliefs, use, and susceptibility, as well as current tobacco product use and sociodemographics. We used weighted logistic and multinomial regression models to explore their associations. Overall, 23.6% were aware of, 8.9% had ever used, and 3.0% currently used HTPs. Younger individuals (vs. 61+ years), those with annual income $50,000+ (vs. <$50,000), and those currently using electronic vaping products (vs. non-users) were more likely to be aware of, to have ever used, and to currently be using HTPs (p < 0.05). Black individuals (vs. White) were more likely to report ever and current HTP use (p < 0.05). Current cigarette smoking was not associated with HTP awareness and use (p > 0.05). Holding favorable HTP beliefs was associated with susceptibility to and more advanced HTP use statuses (p < 0.05). Sociodemographics associated with HTP use may reflect HTP marketing strategies. The lack of association with cigarette smoking suggests HTPs may be unlikely cigarette substitutes. Addressing favorable HTP-related beliefs may prevent dual use.

[Smoking, heated tobacco products, alcohol and diabetes mellitus (update 2023)]

Smoking and second-hand smoke strongly increase incidence of diabetes and probability for its complications. Smoking cessation can lead to weight gain and increased diabetes risk; however, it decreases cardiovascular and total mortality. A basal diagnostics (Fagerström Test, exhaled CO) is the basis for successful smoking cessation. Supporting medication include Varenicline, Nicotine Replacement Therapy and Bupropion. Socio-economic as well as psychological factors play an important role for smoking and smoking cessation. Heated tobacco products (like the E‑cigarette) are no healthy alternative to cigarettes and are associated with increased morbidity and mortality.Moderate consumption of alcohol possibly decreases risk for diabetes and cardiovascular diseases. Selection bias and underreporting in studies maybe contribute to a too optimistic view. On the other hand, alcohol increases in a dose dependant fashion excess morbidity and disability adjusted life years, especially by cancer, liver diseases and infections.

Comparison of effects of tobacco cigarettes, electronic nicotine delivery systems and tobacco heating products on miRNA-mediated gene expression. A systematic review

OBJECTIVES

This work attempts to summarize current knowledge on the effects of cigarettes, electronic nicotine delivery systems and tobacco heating products on miRNA-mediated gene expression regulation and on their possible impact on smoking-related respiratory disease development.

MATERIALS AND METHODS

Literature search by terms combination: 'smoking', 'cigarette' 'THP', 'tobacco heating product', 'ENDS', 'electronic nicotine delivery system', 'e-cigarette', electronic cigarette' and 'miRNA-mediated gene expression' has been performed from October 2021 to February 2022. In this systematic review all relevant literature, including clinical trials, cellular and animal-based studies were included.

RESULTS

Cigarette smoke (CS) significantly altered transcriptome, including miRNAs expression profile. MiRNA-mediated gene expression is mentioned as one of the mechanisms associated with smoking-related respiratory disease development. Differential expression of miRNAs was reduced in aerosol from e-cigarettes (EC) and tobacco heating products (THP) when compared to CS. However, there was a significant alteration of some miRNAs expression when compared to air-controls in both EC and THP.

DISCUSSION

CS negatively affects transcriptome and miRNA-mediated gene expression regulation because of a huge number of hazardous substances which predispose to smoking-related diseases. Despite the reduced effect of ENDS and THP on miRNAs profile compared to CS, differences in expression of miRNAs when compared to air-control were observed, which may be harmful to never-smokers who may perceive such alternative smoking products as non-hazardous. To clearly indicate the role of ENDS and THP in the alteration of miRNA-mediated gene expression and the development of smoking-related respiratory diseases associated with this mechanism, more long-term studies should be performed in the future.

Electronic cigarettes for smoking cessation

BACKGROUND

Electronic cigarettes (ECs) are handheld electronic vaping devices which produce an aerosol by heating an e-liquid. Some people who smoke use ECs to stop or reduce smoking, although some organizations, advocacy groups and policymakers have discouraged this, citing lack of evidence of efficacy and safety. People who smoke, healthcare providers and regulators want to know if ECs can help people quit smoking, and if they are safe to use for this purpose. This is a review update conducted as part of a living systematic review.

OBJECTIVES

To examine the effectiveness, tolerability, and safety of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term smoking abstinence.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and PsycINFO to 1 July 2022, and reference-checked and contacted study authors.  SELECTION CRITERIA: We included randomized controlled trials (RCTs) and randomized cross-over trials, in which people who smoke were randomized to an EC or control condition. We also included uncontrolled intervention studies in which all participants received an EC intervention. Studies had to report abstinence from cigarettes at six months or longer or data on safety markers at one week or longer, or both.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking after at least six months follow-up, adverse events (AEs), and serious adverse events (SAEs). Secondary outcomes included the proportion of people still using study product (EC or pharmacotherapy) at six or more months after randomization or starting EC use, changes in carbon monoxide (CO), blood pressure (BP), heart rate, arterial oxygen saturation, lung function, and levels of carcinogens or toxicants, or both. We used a fixed-effect Mantel-Haenszel model to calculate risk ratios (RRs) with a 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated mean differences. Where appropriate, we pooled data in meta-analyses.

MAIN RESULTS

We included 78 completed studies, representing 22,052 participants, of which 40 were RCTs. Seventeen of the 78 included studies were new to this review update. Of the included studies, we rated ten (all but one contributing to our main comparisons) at low risk of bias overall, 50 at high risk overall (including all non-randomized studies), and the remainder at unclear risk. There was high certainty that quit rates were higher in people randomized to nicotine EC than in those randomized to nicotine replacement therapy (NRT) (RR 1.63, 95% CI 1.30 to 2.04; I2 = 10%; 6 studies, 2378 participants). In absolute terms, this might translate to an additional four quitters per 100 (95% CI 2 to 6). There was moderate-certainty evidence (limited by imprecision) that the rate of occurrence of AEs was similar between groups (RR 1.02, 95% CI 0.88 to 1.19; I2 = 0%; 4 studies, 1702 participants). SAEs were rare, but there was insufficient evidence to determine whether rates differed between groups due to very serious imprecision (RR 1.12, 95% CI 0.82 to 1.52; I2 = 34%; 5 studies, 2411 participants). There was moderate-certainty evidence, limited by imprecision, that quit rates were higher in people randomized to nicotine EC than to non-nicotine EC (RR 1.94, 95% CI 1.21 to 3.13; I2 = 0%; 5 studies, 1447 participants). In absolute terms, this might lead to an additional seven quitters per 100 (95% CI 2 to 16). There was moderate-certainty evidence of no difference in the rate of AEs between these groups (RR 1.01, 95% CI 0.91 to 1.11; I2 = 0%; 5 studies, 1840 participants). There was insufficient evidence to determine whether rates of SAEs differed between groups, due to very serious imprecision (RR 1.00, 95% CI 0.56 to 1.79; I2 = 0%; 8 studies, 1272 participants). Compared to behavioural support only/no support, quit rates were higher for participants randomized to nicotine EC (RR 2.66, 95% CI 1.52 to 4.65; I2 = 0%; 7 studies, 3126 participants). In absolute terms, this represents an additional two quitters per 100 (95% CI 1 to 3). However, this finding was of very low certainty, due to issues with imprecision and risk of bias. There was some evidence that (non-serious) AEs were more common in people randomized to nicotine EC (RR 1.22, 95% CI 1.12 to 1.32; I2 = 41%, low certainty; 4 studies, 765 participants) and, again, insufficient evidence to determine whether rates of SAEs differed between groups (RR 1.03, 95% CI 0.54 to 1.97; I2 = 38%; 9 studies, 1993 participants).  Data from non-randomized studies were consistent with RCT data. The most commonly reported AEs were throat/mouth irritation, headache, cough, and nausea, which tended to dissipate with continued EC use. Very few studies reported data on other outcomes or comparisons, hence evidence for these is limited, with CIs often encompassing clinically significant harm and benefit.

AUTHORS' CONCLUSIONS

There is high-certainty evidence that ECs with nicotine increase quit rates compared to NRT and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain. More studies are needed to confirm the effect size. Confidence intervals were for the most part wide for data on AEs, SAEs and other safety markers, with no difference in AEs between nicotine and non-nicotine ECs nor between nicotine ECs and NRT. Overall incidence of SAEs was low across all study arms. We did not detect evidence of serious harm from nicotine EC, but longest follow-up was two years and the number of studies was small. The main limitation of the evidence base remains imprecision due to the small number of RCTs, often with low event rates, but further RCTs are underway. To ensure the review continues to provide up-to-date information to decision-makers, this review is a living systematic review. We run searches monthly, with the review updated when relevant new evidence becomes available. Please refer to the Cochrane Database of Systematic Reviews for the review's current status.

Knowledge, beliefs, attitude, and practices of E-cigarette use among dental students: A multinational survey

Background

E-cigarette use is a trend worldwide nowadays with mounting evidence on associated morbidities and mortality. Dentists can modify the smoking behaviors of their patients. This study aimed to explore the knowledge, beliefs, attitude, and practice of E-cigarette use among dental students.

Materials and methods

This multinational, cross-sectional, questionnaire-based study recruited undergraduate dental students from 20 dental schools in 11 countries. The outcome variable was current smoking status (non-smoker, E-cigarette user only, tobacco cigarette smoker only, dual user). The explanatory variables were country of residence, sex, age, marital status, and educational level. Multiple linear regression analysis was performed to explore the explanatory variables associated with E-cigarette smoking.

Results

Of the 5697 study participants, 5156 (90.8%) had heard about E-cigarette, and social media was the most reported source of information for 33.2% of the participants. For the 5676 current users of E-cigarette and/or tobacco smoking, 4.5% use E-cigarette, and 4.6% were dual users. There were significant associations between knowledge and country (P< 0.05), educational level (B = 0.12; 95% CI: 0.02, 0.21; P = 0.016) and smoking status (P< 0.05). The country of residence (P< 0.05) and smoking status (P< 0.05) were the only statistically significant factors associated with current smoking status. Similarly, there were statistically significant associations between attitude and country (P< 0.05 for one country only compared to the reference) and history of previous E-cigarette exposure (B = -0.52; 95% CI: -0.91, -0.13; P = 0.009). Also, the practice of E-cigarettes was significantly associated with country (P< 0.05 for two countries only compared to the reference) and gender (B = -0.33; 95% CI: -0.52, -0.13; P = 0.001).

Conclusion

The knowledge of dental students about E-cigarette was unsatisfactory, yet their beliefs and attitudes were acceptable. Topics about E-cigarette should be implemented in the dental curriculum.

Association between Heated Tobacco Product Use during Pregnancy and Fetal Growth in Japan: A Nationwide Web-Based Survey

Combustible cigarette smoking impacts fetal growth during pregnancy. However, the risk associated with heated tobacco products (HTPs) remains unclear. This nationwide cross-sectional study investigated whether HTP use during pregnancy is associated with small for gestational age (SGA) outcomes among 5647 post-delivery women with singleton pregnancies, which were divided into four groups: lifetime never-smokers, former smokers before pregnancy, and current smokers for each of the tobacco products during pregnancy (sole HTP and sole combustion smokers). Information on the prevalence of SGA, defined as birth weight and height below the 10th percentile, was retrieved from the Maternal and Child Health Handbooks of post-delivery women. Using logistic regression, the association between sole HTP smokers during pregnancy and SGA, adjusted for covariates, with lifetime never-smokers as reference, was investigated. The prevalence was: current sole HTP smokers during pregnancy, 1.8% (102/5647); and SGA, 2.9% (164/5647). Sole HTP smokers during pregnancy had a higher prevalence of SGA (5.9% [6/102] vs. 2.7% [111/4144]) with an adjusted odds ratio (OR) of 2.50 (95% confidence interval [CI], 1.03-6.05) than lifetime never-smokers. Among sole combustion smokers, the adjusted OR for SGA was 1.95 (95% CI, 0.81-4.67). In Japan, HTP smoking during pregnancy may be associated with an increased risk for SGA.