Modelling continuous abstinence rates over time from clinical trials of pharmacological interventions for smoking cessation

Nicotine strength of e-liquids used by adult vapers in Great Britain: A population survey 2016 to 2024

BACKGROUND AND AIMS

In March 2024, the UK government announced plans to introduce a Vaping Products Duty that will tax e-liquids based on their nicotine strength. This study examined trends in the nicotine strength of e-liquids used by adult vapers and differences in those currently used across relevant subgroups.

DESIGN

Nationally-representative, cross-sectional household survey, July 2016 to January 2024.

SETTING

Great Britain.

PARTICIPANTS

7981 adult vapers.

MEASUREMENTS

Participants were asked whether the e-cigarette they mainly use contains nicotine (yes/no) and the e-liquid strength (no nicotine, >0-≤ 6, 7-11, 12-19 or ≥20 mg/ml). We also collected information on the main device type used (disposable/refillable/pod), age, gender, occupational social grade, history of ≥1 mental health conditions, smoking status and (among past-year smokers) level of cigarette addiction.

FINDINGS

The proportion of vapers in England using high-strength (≥20 mg/ml) e-liquids increased from an average of 3.8% (95% confidence interval [CI] = 2.9-5.0) up to June 2021 to 32.5% (CI = 27.9-37.4) in January 2024 (the vast majority of whom [93.3% in January 2024] reported using exactly 20 mg/ml; the legal limit). This rise was most pronounced among those using disposable e-cigarettes, those aged 18-24 years and all smoking statuses (including never smokers) except long-term (≥1y) ex-smokers. Of those surveyed in 2022-2024 in Great Britain, overall, 89.5% (CI = 88.1-90.8) said they usually used e-cigarettes containing nicotine, 8.7% (CI = 7.5-10.0) used nicotine-free e-cigarettes, and 1.8% (CI = 1.2-2.4) were unsure. The proportion using ≥20 mg/ml was higher among those mainly using disposable (47.9%) compared with pod (16.3%) or refillable (11.5%) devices; never smokers (36.0%), current smokers (28.8%) or recent (<1y) ex-smokers (27.4%), compared with long-term ex-smokers (13.9%); and younger (16-24y; 44.2%) compared with older (≥25y; range 9.4-25.1%) age groups. There were no notable differences across other subgroups of interest.

CONCLUSIONS

Use of high-strength nicotine e-liquids in England appears to have increased sharply in recent years. Most adult vapers in Great Britain appear to use e-cigarettes that contain nicotine but different subgroups use different strengths: nicotine strengths tend to be higher among those who mainly use disposable devices and those aged 16-24y, and lower among long-term ex-smokers.

Vaping cessation interventions: a systematic review and meta-analysis

OBJECTIVE

Electronic nicotine delivery systems (ENDS), such as e-cigarettes, have surged in popularity. While long-term risks remain unclear, known dangers include nicotine addiction, E-cigarette or Vaping Use-Associated Lung Injury and potential extrapulmonary effects on the heart, immune system and neurodevelopment. Addressing ENDS addiction may require strategies akin to smoking cessation. However, evidence is lacking; there are no currently approved vaping-cessation aids. The objective of this review is to summarise the available literature addressing interventions for vaping cessation.

DATA SOURCES AND STUDY SELECTION

A librarian-assisted search was conducted in MEDLINE, Embase and Scopus, as well as preprints in Europe PMC, Open Science Framework, and the grey literature searches until January 2024. Six included studies used self-report methods to determine the abstinence rate, while one study used cotinine-level-verified self-reported abstinence. We included randomised controlled trials (RCTs) that examine 'rates of vaping cessation' outcomes. An intention-to-treat approach was used for data extraction, and random-effects meta-analyses models were applied.

DATA SYNTHESIS

Seven RCTs were included, which studied pharmacological therapy, digital interventions and/or educational content. The primary meta-analyses demonstrated a statistically significant increase in the odds of achieving 7-day point prevalence abstinence (PPA) (OR 1.52, 95% CI 1.15 to 2.01, number of participants=3244, moderate-certainty) and continuous abstinence (OR 2.71, 95% CI 1.31 to 5.61, number of participants=164, low-certainty) following intervention. A non-significant increase in odds was noted at 30-day PPA (OR 1.32, 95% CI 0.72 to 2.42, number of participants=1994, very low certainty).

CONCLUSIONS

Vaping cessation interventions increase 7-day PPA rates at 1-12 months follow-up and this was consistent across prespecified subgroup analyses of the intervention type, outcome and duration of follow-up. More high-quality studies with reproducible findings are needed to enhance the certainty of the evidence and guide clinical interventions.

PROSPERO REGISTRATION NUMBER

CRD42022383670.

Readiness to stop smoking and subsequent switching away to electronic nicotine delivery systems among adults who smoke cigarettes

Background: Adults who smoke cigarettes (AWS) who switch to electronic nicotine delivery systems (ENDS) are likely to reduce their health risks.Objectives: To explore ENDS-users' readiness to stop smoking (RTSS) when adopting ENDS, the prospective association of RTSS and switching away from smoking (past-30-day abstinence), and the role of frequency of JUUL use in switching.Methods: Analyses used data from a naturalistic 2-year longitudinal study of 17,393 AWS (55.4% male) who had purchased a JUUL Starter Kit.Results: Only 20% were planning to stop smoking within 7 days at baseline but had the highest likelihood of switching, 70% at Month-24 (vs. in a year or more: OR = 2.33; 95%CI = 2.13-2.55). Those planning to stop smoking within 30 days (24%), 6 months (24%) or a year or more (27%) had switch rates of 53 ~ 59% at Month-24; those who planned never to quit (6%) had 51% switch rates. Daily ENDS use was prospectively associated with the highest likelihood of subsequent switching (vs. infrequent: OR = 1.68; 95%CI = 1.60-1.77); frequent users (≥20 days/month) also had higher switch rates (OR = 1.22; 95%CI = 1.15-1.28). Descriptively, participants higher on RTSS were more likely to be daily or frequent users, but frequency of use neither interacted with RTSS, nor mediated its association with switching.Conclusions: Most ENDS adopters were not ready to stop smoking, and would not be candidates for cessation treatment. However, a majority - even of those never planning to quit - were abstinent from cigarettes two years later. ENDS may facilitate smoking abstinence in populations not reached by traditional cessation interventions.

Prognosis after switching to electronic cigarettes following percutaneous coronary intervention: a Korean nationwide study

BACKGROUND AND AIMS

Despite the increasing popularity of electronic cigarettes (E-cigarettes), the prognostic impact of switching to E-cigarettes in smokers with coronary artery disease who have undergone percutaneous coronary intervention (PCI) remains unclear.

METHODS

Using a nationwide cohort from the Korean National Health Insurance database, 17 973 adults (≥20 years) identified as smokers (based on a health screening examination within 3 years before PCI) who underwent health screening within 3 years after PCI were enrolled to determine changes in smoking habits. Patients were classified as continued combustible cigarette users, successful quitters, or switchers to E-cigarettes. The group switching to E-cigarettes was further divided into dual users (using both combustible and E-cigarettes) and those exclusively using E-cigarettes. Primary outcomes included major adverse cardiac events (MACEs), a composite of all-cause death, spontaneous myocardial infarction, and repeat revascularization.

RESULTS

Among the total population, 8951 patients (49.8%) continued using combustible cigarettes, 1694 (9.4%) were switched to E-cigarettes, and 7328 (40.7%) successfully quit smoking after PCI. During a median follow-up of 2.4 years, the cumulative incidence of MACE was lower among E-cigarette switchers (10%) or quitters (13.4%) than among continued combustible cigarette users (17%). When continued combustible cigarette users were used as the reference, the multivariable-adjusted hazard ratios with 95% confidence intervals for MACE were 0.82 (0.69-0.98) for switchers to E-cigarettes and 0.87 (0.79-0.96) for successful quitters. Compared with dual users, entirely switching to E-cigarettes was associated with a significantly lower MACE risk (hazard ratio 0.71; 95% confidence interval 0.51-0.99).

CONCLUSIONS

Among smokers who underwent PCI for coronary artery disease, switching to E-cigarette use (particularly complete transition) or quitting smoking was associated with reduced MACE risk than with continued combustible cigarette use.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT06338761.

Mailed smoking cessation support for Aboriginal and Torres Strait Islander people who smoke: protocol for a hybrid type 1 effectiveness - implementation trial

INTRODUCTION

Smoking is the leading preventable cause of death and the single most significant risk behaviour contributing to adverse health conditions among Aboriginal and Torres Strait Islander people. There is an urgent need for innovative approaches to support reductions in smoking prevalence. This study will assess the implementation and effectiveness of a mailed smoking cessation support programme that includes nicotine replacement therapy (NRT) (Which Way Quit Pack) for Aboriginal and Torres Strait Islander people.

METHODS AND ANALYSIS

A hybrid type 1 effectiveness-implementation trial will be conducted in Australia from 2023 to 2025. A sample of 500 Aboriginal and Torres Strait Islander people aged over 16 who smoke will be recruited using social media. All participants will: (a) receive a mailed Which Way Quit Pack that includes pamphlets and resources on quitting, information about quit smoking support options (MyQuitBuddy App) and a selection of merchandise; (b) be offered a referral to Aboriginal Quitline; and (c) be offered a free 12-week mail out course of combination NRT. Outcome data will be obtained using quantitative surveys and qualitative Yarning. Effectiveness outcomes will include assessment of 7-day point prevalence, continuous abstinence and quit attempts at 3- and 6-month follow-up. Implementation outcomes will include assessment of recruitment and retention rates, intervention uptake and adherence, and intervention acceptability.Cessation data will be analysed using an intention-to-treat principle with all individuals lost to follow-up considered as smoking. Yarns will be analysed by Aboriginal and Torres Strait Islander members of the research team privileging Collaborative Yarning, with the support of a reflexive thematic analysis approach that will identify themes while also reflecting potential biases and perspectives of the researcher throughout the analysis process.

ETHICS AND DISSEMINATION

Ethics approvals were obtained from Aboriginal Health and Medical Research Council Ethics Committee of NSW (1894/21) and the University of Newcastle (H-2022-0174). Findings will be disseminated through publications, conference presentations and sharing with relevant government bodies.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12623001021662).

Switching Away From Smoking and Reduction in Cigarette Consumption Among U.S. Adult Purchasers of the JUUL System Across 24 Months Including Diverse Subpopulations Disproportionately Affected by Cigarette Smoking

INTRODUCTION

Electronic nicotine-delivery systems (ENDS) can reduce tobacco-related health risks for adults who smoke cigarettes (AWS) by facilitating complete switching away from cigarettes. However, little is known about ENDS use and switching among subpopulations that have been disproportionately affected by smoking.

AIMS AND METHODS

AWS (age ≥ 21 years) were recruited following their first purchase of a JUUL Starter Kit in 2018. Participants who self-reported switching (no past-30-day cigarette smoking) at 1-, 2-, 3-, 6-, 9-, 12-, 15-, 18-, 21-, and 24-month follow-ups. Percent switched and percent with substantial smoking reduction (≥50% decrease in cigarettes per day among those who continued smoking) were calculated. Analyses focused on racial and ethnic minorities, persons with low income and education levels, sexual minorities, and those with mental and physical health conditions.

RESULTS

Overall rates of switching away from cigarettes increased across follow-ups to 51.2% (month-12) to 58.6% (month-24, 87% of whom used ENDS). Among those who continued to smoke at 24 months, 45.4% reduced cigarettes per day by ≥ 50%. Rates of switching and substantial smoking reduction were largely similar across subgroups, with some statistically significant, but small, differences in month-24 switching rates (eg, education, mental and physical health conditions; switch rate range: 42%-57%).

CONCLUSIONS

AWS demonstrated progressively increasing switching rates over 2 years after purchasing JUUL products. Similar trends in switching and smoking reduction were observed across populations disproportionately affected by smoking. By facilitating switching and smoking reduction, ENDS products such as JUUL may provide an opportunity to reduce smoking-related harm among some populations disproportionately affected by smoking, potentially reducing tobacco-related health disparities.

IMPLICATIONS

ENDS have the potential to benefit population health if they can replace cigarettes. This benefit must extend to populations disproportionately affected by smoking. In this real-world study, 59% of JUUL purchasers reported complete switching 2 years later (no past-30-day smoking, with most continuing to use ENDS). Furthermore, 45% of those who continued to smoke reduced cigarette consumption by at least half. These rates of switching and smoking reduction were largely comparable across populations disproportionately affected by smoking (defined, eg, by ethnicity and income). ENDS can serve as an effective harm reduction strategy to complement current efforts to reduce tobacco-related disparities.

Treating Tobacco Dependency in National Health Service Workers in Greater Manchester: An Evaluation of a Bespoke Digital Service

Introduction

Treating tobacco dependency in National Health Service (NHS) workers delivers substantial benefits at an individual, population, and health care system level. We report the outcomes from the Greater Manchester Integrated Care Partnership's tobacco dependency treatment program for NHS workers which includes 6-months' access to behavioral support and 12 weeks of treatment through a digital application.

Methods

Aggregate results for all participants across the program from January 1, 2022, to September 1, 2023, are reported including a deep-dive evaluation of 300 participants recruited to provide chemically validated outcomes.

Results

A total of 1567 NHS workers participated in the program within the evaluation period, completing 24,048 sessions with specialist advisors within the application, ordering 18,710 nicotine vape liquids, 6927 nicotine patches, and 297 short-acting nicotine products. Users reported achieving 89,464 smoke-free days, 1,258,069 less cigarettes smoked, and a financial saving of £622,231. The deep-dive evaluation revealed a CO-verified 12-week abstinence rate of 37% (111 of 300).

Conclusion

This evaluation provides assurance of clinical effectiveness within a bespoke digital tobacco dependency treatment program for NHS workers across an Integrated Care Partnership.

How a 5-Day Stay in the Tobacco-Free Environment of the Stoptober House Supports Individuals to Quit Smoking: A Mixed Methods Pilot Study

INTRODUCTION

The Stoptober House is part of the annual national Stoptober smoking cessation campaign in the Netherlands. During the first week of October, 48 volunteers resided in the tobacco-free Stoptober House for 5 days and received smoking cessation counseling. This pilot study explored how the Stoptober House may have facilitated smoking cessation among participants.

METHODS

We included 48 individuals who were selected for the Stoptober House (intervention group) and 67 individuals who were not selected (control group). Surveys were conducted at baseline, immediately after 2 and 8 weeks of post-intervention. We compared self-reported abstinence, psychosocial mediators related to smoking cessation, and perceived active elements of the Stoptober House between the intervention and control groups using t/χ2 tests and linear mixed model (LMM) analysis. Sixteen semi-structured qualitative interviews were conducted to explore participants' perspectives on the elements contributing to their success in quitting smoking.

RESULTS

At 8 weeks of follow-up, a higher proportion of participants in the intervention group (24/48 [50%]) reported being abstinent compared to the control group (5/67 [7%]; p < 0.001). Among participants who reported making a quit attempt, 22/38 (57.9%) in the intervention group remained abstinent compared to 4/17 (23.5%) in the control group (p = 0.022). The intervention group also exhibited higher self-efficacy to quit smoking throughout the follow-up period and higher social support immediately after the Stoptober House. No significant differences were observed in other psychosocial factors. The interviews highlighted several perceived elements of the Stoptober House that contributed to smoking cessation success, including restricted smoking opportunities, access to smoking cessation counselors, and peer support.

CONCLUSION

This pilot study suggests that the Stoptober House provides support that can help people quit smoking. Further research is needed to confirm these findings and determine the cost-effectiveness of this intervention in promoting long-term abstinence among specific groups of smokers.

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.

Mobile chat messaging for preventing relapse among people who recently quit smoking: Study protocol for a randomized controlled trial

Objective

Most smokers who achieve short-term abstinence relapse even when aided by evidence-based cessation treatment. Mobile health presents a promising but largely untested avenue for providing adjunct behavioral support for relapse prevention. This paper presents the rationale and design of a randomized controlled trial aimed at evaluating the effectiveness of personalized mobile chat messaging support for relapse prevention among people who recently quit smoking.

Methods

This is a two-arm, assessor-blinded, randomized controlled trial conducted in two clinic-based smoking cessation services in Hong Kong. An estimated 586 daily tobacco users who have abstained for 3 to 30 days will be randomized (1:1) to intervention group or control group. Both groups receive standard-of-care smoking cessation treatment from the services. The intervention group additionally receives 3-month relapse prevention support via mobile chat messaging, including cessation advice delivered by a live counselor and access to a supportive chatbot via WhatsApp. The control group receives text messaging on generic cessation advice for 3 months as attention control. The primary outcome is tobacco abstinence verified by an exhaled carbon monoxide of <5 parts per million or a negative salivary cotinine test at 6 months after randomization. Secondary outcomes include self-reported 6-month prolonged tobacco abstinence, 7-day point-prevalent abstinence, and relapse rate. The primary analyses will be by intention-to-treat, assuming participants with missing data are non-abstinent. This trial is registered with ClinicalTrials.gov (NCT05370352) and follows CONSORT-EHEALTH.

Conclusion

This trial will provide new evidence on the effectiveness of mobile chat messaging as a scalable and accessible intervention for relapse prevention.

Using varenicline in combination with electronic nicotine delivery systems (ENDS)

BACKGROUND

Varenicline is efficacious for smoking cessation, but a return to smokingusually occurs after treatment ends. Electronic nicotine delivery systems (ENDS) may enhance smoking reduction and cessation by providing a behavioral substitute for smoking and may deter smoking in the long term if an individual's nicotine dependence can be transferred to ENDS. The goal of this study was to evaluate varenicline in conjunction with ENDS to promote switching to ENDS.

METHODS

Twenty-five individuals who smoked cigarettes, interested in switching but not seeking cessation treatment, received ENDS for 13 weeks; during weeks 2-13 they received varenicline. Assessments included self-reported cigarette and ENDS use, expired air carbon monoxide (CO), reward ratings, tolerability/side effects, and dependence measures.

RESULTS

Cigarette smoking decreased from 15.6 cigarettes/day (SD=5.6) at baseline to 2.8 cigarettes/day (SD=5.1) at week 13 (paired t(22)=10.24, p<0.0001). 28% of participants were confirmed to be abstinent in the last 4 weeks of treatment. ENDS use remained relatively constant, averaging 11.8 occasions per day (SD=10.6). Cigarette dependence (assessed by time to first use of the day) decreased after introduction of ENDS (paired t(23) = -3.27, p=0.003), and again after the first week of full-dose varenicline (paired t(23) = -4.27, p=0.0003). Dependence on ENDS did not change, starting out lower than cigarettes (paired t(21) = 5.52, p<0.0001), but ending higher (paired t(22) = 2.94, p=0.008). Smoking satisfaction declined markedly, while satisfaction for ENDS remained relatively constant. Treatment tolerability and adherence were high.

CONCLUSIONS

ENDS in combination with varenicline shows promise as a means to reduce dependence on cigarettes and facilitate switching from cigarettes to ENDS.

Switching away from smoking at 12 months among adult JUUL users varying in recent history of quit attempts made with and without smoking cessation medication

Some smokers switch away from smoking using e-cigarettes, but guidelines recommend trying approved medications first. We analyzed switching in adult smokers using JUUL by their recent history of quit attempts and use of smoking cessation medications. Participants were 8511 adult (21+) established smokers (at baseline), in which 50.3% are daily smokers, in a longitudinal observational study who completed a survey 12 months after first purchasing a JUUL Starter Kit. At baseline, participants reported attempts to quit smoking in the prior year and use of pharmacotherapy (nicotine replacement therapy [NRT] or prescription medication) in their most recent attempt. The outcomes were switching (self-reported no past-30-day smoking) and 50%+ reductions in cigarette consumption. Multivariable analyses were adjusted for baseline covariates. Two thirds of the participants had made a quit attempt in the year before purchasing JUUL. Overall, 59% [58%, 60%] had switched at 12 months. Switching was more likely in those who had used NRT and who attempted quitting without medication versus those who used prescription medications or made no quit attempt. In adjusted multivariable analyses, only making a past-year quit attempt (vs. not) was associated with higher odds of switching (OR = 1.15 [1.04, 1.28]). Over 60% of dual users reduced cigarette consumption by ≥50%. These associations were largely similar in daily smokers. Twelve months after purchasing JUUL, almost all smokers reported either switching or reducing their smoking by 50%+, including those who had recently failed to quit smoking with approved pharmacotherapies. E-cigarettes provide an alternative route to abstinence from smoking for smokers with a history of cessation and cessation treatment failure.

Repetitive transcranial magnetic stimulation for smoking cessation: Next steps for translation and implementation into clinical practice

Tobacco smoking is a significant determinant of preventable morbidity and mortality worldwide. It is now possible to modulate the activity of the neurocircuitry associated with nicotine dependence using repetitive Transcranial Magnetic Stimulation (rTMS), a non-invasive neurostimulation approach, which has recently demonstrated efficacy in clinical trials and received regulatory approval in the US and Canada. However there remains a paucity of replication studies and real-world patient effectiveness data as access to this intervention is extremely limited. There are a number of unique challenges related to the delivery of rTMS that need to be addressed prior to widespread adoption and implementation of this treatment modality for smoking cessation. In this paper, we review the accessibility, scientific, technological, economical, and social challenges that remain before this treatment can be translated into clinical practice. By addressing these remaining barriers and scientific challenges with rTMS for smoking cessation and delineating implementation strategies, we can greatly reduce the burden of tobacco-related disease worldwide.

Right inferior frontal gyrus theta-burst stimulation reduces smoking behaviors and strengthens fronto-striatal-limbic resting-state functional connectivity: a randomized crossover trial

Introduction

Functional and anatomical irregularities in the right inferior frontal gyrus (rIFG), a ventrolateral prefrontal region that mediates top-down inhibitory control over prepotent behavioral responding, are implicated in the ongoing maintenance of nicotine dependence (ND). However, there is little research on the effects of neuromodulation of the rIFG on smoking behavior, inhibitory control, and resting-state functional connectivity (rsFC) among individuals with ND.

Methods

In this double-blind, crossover, theta-burst stimulation (TBS) study, adults with ND (N = 31; female: n = 15) completed a baseline session and were then randomized to two counterbalanced sessions of functionally neuronavigated TBS to the rIFG: continuous TBS (cTBS) on 1 day and intermittent TBS (iTBS) on another. Differences in cigarette cravings, smoking, and fronto-striatal-limbic rsFC were assessed.

Results

Relative to baseline, cTBS significantly reduced appetitive and withdrawal cravings immediately after treatment. The effects of cTBS on withdrawal craving persisted for 24 h, as well as produced a reduction in smoking. Furthermore, cTBS significantly strengthened rsFC between the rIFG pars opercularis and subcallosal cingulate (fronto-striatal circuit), and between the rIFG pars opercularis and the right posterior parahippocampal gyrus (fronto-limbic circuit). At post-24 h, cTBS-induced increase in fronto-striatal rsFC was significantly associated with less appetitive craving, while the increase in fronto-limbic rsFC was significantly associated with less withdrawal craving and smoking.

Discussion

These findings warrant further investigation into the potential value of rIFG cTBS to attenuate smoking behavior among individuals with ND.

Classification of Lapses in Smokers Attempting to Stop: A Supervised Machine Learning Approach Using Data From a Popular Smoking Cessation Smartphone App

INTRODUCTION

Smoking lapses after the quit date often lead to full relapse. To inform the development of real time, tailored lapse prevention support, we used observational data from a popular smoking cessation app to develop supervised machine learning algorithms to distinguish lapse from non-lapse reports.

AIMS AND METHODS

We used data from app users with ≥20 unprompted data entries, which included information about craving severity, mood, activity, social context, and lapse incidence. A series of group-level supervised machine learning algorithms (eg, Random Forest, XGBoost) were trained and tested. Their ability to classify lapses for out-of-sample (1) observations and (2) individuals were evaluated. Next, a series of individual-level and hybrid algorithms were trained and tested.

RESULTS

Participants (N = 791) provided 37 002 data entries (7.6% lapses). The best-performing group-level algorithm had an area under the receiver operating characteristic curve (AUC) of 0.969 (95% confidence interval [CI] = 0.961 to 0.978). Its ability to classify lapses for out-of-sample individuals ranged from poor to excellent (AUC = 0.482-1.000). Individual-level algorithms could be constructed for 39/791 participants with sufficient data, with a median AUC of 0.938 (range: 0.518-1.000). Hybrid algorithms could be constructed for 184/791 participants and had a median AUC of 0.825 (range: 0.375-1.000).

CONCLUSIONS

Using unprompted app data appeared feasible for constructing a high-performing group-level lapse classification algorithm but its performance was variable when applied to unseen individuals. Algorithms trained on each individual's dataset, in addition to hybrid algorithms trained on the group plus a proportion of each individual's data, had improved performance but could only be constructed for a minority of participants.

IMPLICATIONS

This study used routinely collected data from a popular smartphone app to train and test a series of supervised machine learning algorithms to distinguish lapse from non-lapse events. Although a high-performing group-level algorithm was developed, it had variable performance when applied to new, unseen individuals. Individual-level and hybrid algorithms had somewhat greater performance but could not be constructed for all participants because of the lack of variability in the outcome measure. Triangulation of results with those from a prompted study design is recommended prior to intervention development, with real-world lapse prediction likely requiring a balance between unprompted and prompted app data.

Lottery incentives for smoking cessation at the workplace: design and protocol of the smoke-free lottery - a cluster randomized trial

BACKGROUND

Smoking is the leading behavioral risk factor for the loss of healthy life years. Many smokers want to quit, but have trouble doing so. Financial incentives in workplace settings have shown promising results in supporting smokers and their design influences their impact. Lotteries that leverage behavioral economic insights might improve the effectiveness of workplace cessation support.

METHODS AND DESIGN

We examine in a cluster randomized trial if a workplace cessation group training paired with lottery deadlines will increase continuous abstinence rates over and above the cessation training alone. Organizations are randomized to either the control arm or lottery arm. The lotteries capitalize regret aversion by always informing winners at the deadline, but withholding prizes if they smoked. In the lottery-arm, winners are drawn out of all participants within a training group, regardless of their smoking status. In weeks 1-13 there are weekly lotteries. Winners are informed about their prize (€50), but can only claim it if they did not smoke that week, validated biochemically. After 26 weeks, there is a long-term lottery where the winners are informed about their prize (vacation voucher worth €400), but can only claim it if they were abstinent between weeks 13 and 26. The primary outcome is continuous abstinence 52 weeks after the quit date.

DISCUSSION

There is a quest for incentives to support smoking cessation that are considered fair, affordable and effective across different socioeconomic groups. Previous use of behavioral economics in the design of lotteries have shown promising results in changing health behavior. This cluster randomized trial aims to demonstrate if these lotteries are also effective for supporting smoking cessation. Therefore the study design and protocol are described in detail in this paper. Findings might contribute to the application and development of effective cessation support at the workplace.

TRIAL REGISTRATION

Netherlands Trial Register Identifier: NL8463 . Date of registration: 17-03-2020.

Mobile Chat Messaging for Preventing Smoking Relapse Amid the COVID-19 Pandemic: A Pilot Randomized Controlled Trial

INTRODUCTION

The ongoing COVID-19 pandemic had reduced access to traditional, in-person smoking cessation treatment. We examined the feasibility, acceptability, and potential effectiveness of mobile chat messaging in preventing smoking relapse in smokers who have recently quit smoking.

METHODS

In this assessor-blinded, pilot randomized controlled trial in five cessation clinics, we recruited adult daily smokers who had been receiving cessation treatments and abstained for 3 to 30 days. The intervention group received real-time, personalized chat messaging on relapse prevention via WhatsApp for 3 months. The control group received generic text messaging on the harms of smoking and benefits of quitting for 3 months. The primary outcome was carbon monoxide-validated abstinence at 6 months post-treatment initiation. The trial was registered with ClinicalTrials.gov (NCT04409496).

RESULTS

From June to July 2020, 108 of 130 (83%) eligible subjects were randomized to the intervention (N = 54) or control (N = 54) groups. The retention rate was 93% at 3 months (end of treatment) and 85% at 6 months. In the intervention group, 80% of participants responded to the chat messages at least once; 43% continuously engaged with the intervention over the 3-month intervention period. By intention-to-treat, validated abstinence at 6 months was higher in the intervention than control group (31% vs. 22%), with a relative risk of 1.72 (95% CI = 0.91% to 3.23%; p = .09) after adjusting for pre-quit nicotine dependence, duration of abstinence, and cessation treatment at baseline.

CONCLUSIONS

This pilot trial showed the feasibility and acceptability of mobile chat messaging for relapse prevention with preliminary evidence on its effectiveness in increasing validated abstinence.

IMPLICATIONS

Smoking relapse is the most likely outcome of smoking cessation attempts and an undertreated problem. This pilot trial showed the feasibility and acceptability of personalized chat messaging via WhatsApp for relapse prevention in recent abstainers amid the COVID-19 pandemic. The higher carbon monoxide-validated abstinence rate in participants who received chat messaging than controls showed preliminary evidence on the effectiveness of the intervention. Fully powered trials are warranted to test the intervention.

Koori Quit Pack mailout smoking cessation support for Aboriginal and Torres Strait Islander people who smoke: a feasibility study protocol

INTRODUCTION

Smoking remains the leading preventable cause of death for Aboriginal and Torres Strait Islander people in Australia. Aboriginal and Torres Strait Islander people who smoke are more likely to make a quit attempt than their non-Aboriginal counterparts but less likely to sustain the quit attempt. There is little available evidence specifically for and by Indigenous peoples to inform best practice smoking cessation care.The provision of a free Koori Quit Pack with optional nicotine replacement therapy sent by mail may be a feasible, acceptable and effective way to access stop smoking support for Aboriginal and Torres Strait Islander peoples.

METHODS AND ANALYSIS

An Aboriginal-led, multisite non-randomised single-group, pre-post feasibility study across three states in Australia will be conducted. Participants will be recruited via service-targeted social media advertising and during usual care at their Aboriginal Community Controlled Health Services. Through a process of self-referral, Aboriginal and Torres Strait Islander people who smoke daily will complete a survey and receive mailout smoking cessation support. Data will be collected over the phone by an Aboriginal Research Assistant. This pilot study will inform the development of a larger, powered trial.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the Aboriginal Health & Medical Research Council Ethics Committee of New South Wales (NSW) (#1894/21) and the University of Newcastle (#H-2022-0174). Findings will be reported through peer-reviewed journals and presentations at relevant local, national and international conferences. The findings will be shared with the NSW and Victoria Quitline, Aboriginal Health and Medical Research Council and Victorian Aboriginal Community Controlled Organisation and the National Heart Foundation.

TRIAL REGISTRATION NUMBER

ACTRN12622000654752.

Pilot randomized controlled trial evaluating the effect of random nicotine delivery on cigarettes per day and smoke exposure

BACKGROUND

Many smokers report attempting to quit each year, yet most relapse, in part due to exposure to smoking-related cues. It is hypothesized that extinction of the cue-drug association could be facilitated through random nicotine delivery (RND), thus making it easier for smokers to quit. The current study aimed to evaluate the effects of RND on smoking cessation-related outcomes including cigarettes per day (CPD) and exhaled carbon monoxide (CO).

METHODS

Participants were current smokers (>9 CPD) interested in quitting. Novel trans-mucosal, orally dissolving nicotine films, developed by Bionex Pharmaceuticals, were used in the study. The pharmacokinetic profile of these films was assessed in single (Experiment 1) and multiple-dose (Experiment 2) administrations prior to the smoking cessation study (Experiment 3). In Experiment 3, participants were randomized 1:1:1 to recieve 4 nicotine films per day of either: placebo delivery (0 mg), steady-state delivery (2 mg), or random nicotine delivery (RND) (0 mg or 4 mg). After two weeks, participants were advised to quit (target quit date, TQD) and were followed up 4 weeks later to collect CPD and CO and to measure dependence (Penn State Cigarette Dependence Index; PSCDI) and craving (Questionnaire of Smoking Urges; QSU-Brief). Means and frequencies were used to describe the data and repeated measures ANOVA was used to determine differences between groups.

RESULTS

The pharmacokinetic studies (Experiment 1 and 2) demonstrated that the films designed for this study delivered nicotine as expected, with the 4 mg film delivering a nicotine boost of approximately 12.4 ng/mL across both the single and the multiple dose administration studies. The films reduced craving for a cigarette and were well-tolerated, overall, and caused no changes in blood pressure or heart rate. Using these films in the cessation study (Experiment 3) (n = 45), there was a significant overall reduction in cigarettes smoked per day (CPD) and in exhaled CO, with no significant differences across groups (placebo, steady-state, RND). In addition, there were no group differences in dependence or craving. Adverse events included heartburn, hiccups, nausea, and to a lesser extent, vomiting and anxiety and there were no differences across groups.

CONCLUSION

Overall, this pilot study found that RND via orally dissolving films was feasible and well tolerated by participants. However, RND participants did not experience a greater reduction in self-reported CPD and exhaled CO, compared with participants in the steady-state and placebo delivery groups. Future studies to evaluate optimal RND parameters with larger sample sizes are needed to fully understand the effect of RND on smoking cessation-related outcomes.

US adult smokers' perceived relative risk on ENDS and its effects on their transitions between cigarettes and ENDS

BACKGROUND

Perceived risk reduction motivates smokers to switch to electronic nicotine delivery systems (ENDS). This research examines US smokers' relative risk perceptions and their prospective association with various behavioral stages of switching to ENDS.

METHODS

Data from the nationally representative, longitudinal Population Assessment of Tobacco and Health (PATH) Adult survey, Waves 1 (2014) through 5 (2019), were analyzed. We assessed the association between the perceived risk of ENDS relative to cigarettes ("less harmful" vs. "equally harmful" or "more harmful") and 1) adoption of ENDS (among never-ENDS-using smokers), 2) complete switching to ENDS (i.e., stopping smoking, among ever-ENDS-using smokers), and 3) avoiding reversion to smoking (among smokers who had switched to ENDS), at the next wave.

RESULTS

The proportion of US smokers perceiving ENDS as less harmful than cigarettes continually decreased, reaching 17.4% in Wave 5 (2019). Current smokers with such belief were more likely to adopt ENDS (aOR 1.31; 95% CI 1.15-1.50) and switch completely to ENDS (aOR 2.24; 95% CI 1.89-2.65) in the subsequent wave. Among smokers who had switched within the past year, such beliefs predicted avoidance of resumption of smoking in the next wave (aOR 0.55; 95% CI 0.33-0.93).

CONCLUSIONS

Smokers' beliefs about the relative risk of ENDS compared to cigarettes had a strong and consistent association with transitions between smoking and ENDS use. Addressing the growing misperception about ENDS has the potential to contribute to public health by encouraging smokers' switching to ENDS.

Novel rapid-acting sublingual nicotine tablet as a cigarette substitution strategy

RATIONALE

Current nicotine replacement products provide a much slower onset of nicotine delivery than cigarettes, and hence are only marginally effective at supplanting cigarette smoking. Therefore, more effective forms of nicotine replacement are needed.

OBJECTIVES

This initial investigation characterized the pharmacokinetic (PK) and subjective effects of a novel sublingual (SL) nicotine tablet designed to deliver nicotine more rapidly to the bloodstream of smokers.

METHODS

Study 1 (N = 6) characterized the pharmacokinetics of a 2 mg nicotine SL tablet in comparison to an FDA-approved, marketed 2 mg nicotine lozenge. Study 2 (N = 24) assessed subjective responses of smokers to a single use of a 1 mg and 2 mg SL tablet.

RESULTS

Study 1 found that the time to maximum blood nicotine concentrations was significantly shorter for the SL tablet (14 min) than for the lozenge (82 min), and the initial rate of nicotine absorption was higher (0.4 ng/mL*min vs. 0.0 ng/mL*min), supporting the hypothesis that the SL tablet delivered nicotine more rapidly. Study 2 found that participants reported immediate relief of nicotine withdrawal symptoms after tablet administration, and craving reduction after the 2 mg tablet approached the degree reported for their usual brands of cigarettes (4.2 vs. 4.6 on a 7-point scale). Other subjective responses showed the tablet to be an appealing alternative to smoking.

CONCLUSIONS

The novel SL tablet studied shows promise as a nicotine substitution strategy for tobacco harm reduction and smoking cessation treatment. Additional studies are warranted to further investigate the potential of this new approach.

Medium- and longer-term cardiovascular effects of e-cigarettes in adults making a stop-smoking attempt: a randomized controlled trial

BACKGROUND

Smoking is a major risk factor for cardiovascular disease and smoking cessation reduces excess risk. E-cigarettes are popular for smoking cessation but there is little evidence on their cardiovascular health effect. Our objective was to compare the medium- and longer-term cardiovascular effects in smokers attempting to quit smoking using e-cigarettes with or without nicotine or prescription nicotine replacement therapy (NRT).

METHODS

This was a single-center, pragmatic three-arm randomized (1:1:1) controlled trial, which recruited adult smokers (≥ 10 cigarettes/day), who were willing to attempt to stop smoking with support (n = 248). Participants were randomized to receive behavioral support with either (a) e-cigarettes with 18 mg/ml nicotine, (b) e-cigarettes without nicotine, and (c) NRT. Flow-mediated dilation (%FMD) and peak cutaneous vascular conductance (CVCmax) responses to acetylcholine (ACh) and sodium nitroprusside (SNP), mean arterial pressure (MAP), and other outcomes were recorded at baseline, 3, and 6 months after stopping smoking. Data were analyzed using generalized estimating equations (GEE).

RESULTS

At 3- and 6-month follow-up, %FMD showed an improvement over baseline in all three groups (e.g., p < 0.0001 at 6 months). Similarly, ACh, SNP, and MAP improved significantly over baseline in all groups both at 3 and 6 months (e.g., ACh: p = 0.004, at 6 months).

CONCLUSIONS

Smokers attempting to quit experienced positive cardiovascular impact after both a 3- and 6-month period. None of the groups (i.e., nicotine-containing and nicotine-free e-cigarettes or NRT) offered superior cardiovascular benefits to the others.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03061253 . Registered on 17 February 2017.

A Randomized Clinical Trial to Assess the Efficacy of a Psychological Treatment to Quit Smoking Assisted with an App: Study Protocol

Numerous studies have shown the efficacy of smoking cessation interventions. However, some challenges, such as relapse rates, remain. The availability of information technologies (ICTs) offers promising opportunities to address such challenges. The aim of this paper is to describe the protocol followed to assess the efficacy of a face-to-face cognitive-behavioral intervention for smoking cessation using a smartphone application as a complement, compared with a control group. A single blind, two-arm, randomized controlled trial is proposed (NCT04765813). The participants will be smokers over 18 years old, who smoke at least eight cigarettes per day. Participants will be randomized to one of two conditions, using a 1:1 allocation ratio: (1) cognitive-behavioral smoking cessation treatment along with an App with active therapeutic components (SinHumo App); or (2) cognitive-behavioral treatment along with the use of a control App (without active components). The experimental App will be used during the eight treatment sessions and for 12 months after the end of treatment. The primary outcome measures will be 7-days point-prevalence abstinence at 12-months follow-up. We expect the experimental App to obtain higher abstinence rates at the end of treatment and at one-year post-treatment follow-ups and lower relapse rates, compared to the control App.

Estimated Failure to Report Unsuccessful Quit Attempts by Type of Cessation Aid: A Population Survey of Smokers in England

Introduction

It has been estimated that smokers tend to fail to report unsuccessful quit attempts that lasted a short time and occurred a longer time ago. However, it is unclear whether the failure to report unsuccessful quit attempts varies by the type of cessation aid used.

Methods

A total of 5,892 smokers aged 16+ years who had made 1+ quit attempts in the past year were surveyed between January 2014 and December 2020 as part of the Smoking Toolkit Study. Respondents indicated when their most recent quit attempt started, how long it lasted, and which cessation aid(s) were used (e.g., unaided, varenicline, and behavioural support). The percentage failure to report for each cessation aid and 95% bootstrap confidence intervals (CIs) were estimated with an established method. Test for equality of proportions was performed to examine whether quit attempts lasting between one day and one week and that started >6 months ago failed to be reported at a different rate depending on the cessation aid used.

Results

We estimated that after three months, 97% (95% CI = 96%-98%) of unaided quit attempts lasting less than one day, 80% (95% CI = 79%-81%) of those lasting between one day and one week, and 60% (95% CI = 59%-61%) of those lasting between one week and one month fail to be reported. Compared with unaided attempts, the estimated percentage failure to report quit attempts that lasted between one day and one week and that started >6 months ago was significantly lower for attempts involving behavioural support (92% of unaided attempts vs. 75% of attempts involving behavioural support, χ ²(1) = 9.29, p = 0.002). No other significant differences were detected.

Conclusions

Smokers in England appear to fail to report a substantial proportion of unsuccessful quit attempts. This failure appears particularly prominent for attempts that last a short time or occurred longer ago and appears lower for attempts involving behavioural support compared with unaided attempts.

Heated tobacco products for smoking cessation and reducing smoking prevalence

BACKGROUND

Heated tobacco products (HTPs) are designed to heat tobacco to a high enough temperature to release aerosol, without burning it or producing smoke. They differ from e-cigarettes because they heat tobacco leaf/sheet rather than a liquid. Companies who make HTPs claim they produce fewer harmful chemicals than conventional cigarettes. Some people report stopping smoking cigarettes entirely by switching to using HTPs, so clinicians need to know whether they are effective for this purpose and relatively safe. Also, to regulate HTPs appropriately, policymakers should understand their impact on health and on cigarette smoking prevalence.

OBJECTIVES

To evaluate the effectiveness and safety of HTPs for smoking cessation and the impact of HTPs on smoking prevalence.  SEARCH METHODS: We searched the Cochrane Tobacco Addiction Group's Specialised Register, CENTRAL, MEDLINE, and six other databases for relevant records to January 2021, together with reference-checking and contact with study authors and relevant groups.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people who smoked cigarettes were randomised to switch to exclusive HTP use or a control condition. Eligible outcomes were smoking cessation, adverse events, and selected biomarkers.  RCTs conducted in clinic or in an ambulatory setting were deemed eligible when assessing safety, including those randomising participants to exclusively use HTPs, smoke cigarettes, or attempt abstinence from all tobacco. Time-series studies were also eligible for inclusion if they examined the population-level impact of heated tobacco on smoking prevalence or cigarette sales as an indirect measure.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcome measures were abstinence from smoking at the longest follow-up point available, adverse events, serious adverse events, and changes in smoking prevalence or cigarette sales. Other outcomes included biomarkers of harm and exposure to toxicants/carcinogens (e.g. NNAL and carboxyhaemoglobin (COHb)). We used a random-effects Mantel-Haenszel model to calculate risk ratios (RR) with 95% confidence intervals (CIs) for dichotomous outcomes. For continuous outcomes, we calculated mean differences on the log-transformed scale (LMD) with 95% CIs. We pooled data across studies using meta-analysis where possible.

MAIN RESULTS

We included 13 completed studies, of which 11 were RCTs assessing safety (2666 participants) and two were time-series studies. We judged eight RCTs to be at unclear risk of bias and three at high risk. All RCTs were funded by tobacco companies. Median length of follow-up was 13 weeks. No studies reported smoking cessation outcomes.  There was insufficient evidence for a difference in risk of adverse events between smokers randomised to switch to heated tobacco or continue smoking cigarettes, limited by imprecision and risk of bias (RR 1.03, 95% CI 0.92 to 1.15; I2 = 0%; 6 studies, 1713 participants). There was insufficient evidence to determine whether risk of serious adverse events differed between groups due to very serious imprecision and risk of bias (RR 0.79, 95% CI 0.33 to 1.94; I2 = 0%; 4 studies, 1472 participants). There was moderate-certainty evidence for lower NNAL and COHb at follow-up in heated tobacco than cigarette smoking groups, limited by risk of bias (NNAL: LMD -0.81, 95% CI -1.07 to -0.55; I2 = 92%; 10 studies, 1959 participants; COHb: LMD -0.74, 95% CI -0.92 to -0.52; I2 = 96%; 9 studies, 1807 participants). Evidence for additional biomarkers of exposure are reported in the main body of the review. There was insufficient evidence for a difference in risk of adverse events in smokers randomised to switch to heated tobacco or attempt abstinence from all tobacco, limited by risk of bias and imprecision (RR 1.12, 95% CI 0.86 to 1.46; I2 = 0%; 2 studies, 237 participants). Five studies reported that no serious adverse events occurred in either group (533 participants). There was moderate-certainty evidence, limited by risk of bias, that urine concentrations of NNAL at follow-up were higher in the heated tobacco use compared with abstinence group (LMD 0.50, 95% CI 0.34 to 0.66; I2 = 0%; 5 studies, 382 participants). In addition, there was very low-certainty evidence, limited by risk of bias, inconsistency, and imprecision, for higher COHb in the heated tobacco use compared with abstinence group for intention-to-treat analyses (LMD 0.69, 95% CI 0.07 to 1.31; 3 studies, 212 participants), but lower COHb in per-protocol analyses (LMD -0.32, 95% CI -1.04 to 0.39; 2 studies, 170 participants). Evidence concerning additional biomarkers is reported in the main body of the review. Data from two time-series studies showed that the rate of decline in cigarette sales accelerated following the introduction of heated tobacco to market in Japan. This evidence was of very low-certainty as there was risk of bias, including possible confounding, and cigarette sales are an indirect measure of smoking prevalence.

AUTHORS' CONCLUSIONS

No studies reported on cigarette smoking cessation, so the effectiveness of heated tobacco for this purpose remains uncertain. There was insufficient evidence for differences in risk of adverse or serious adverse events between people randomised to switch to heated tobacco, smoke cigarettes, or attempt tobacco abstinence in the short-term. There was moderate-certainty evidence that heated tobacco users have lower exposure to toxicants/carcinogens than cigarette smokers and very low- to moderate-certainty evidence of higher exposure than those attempting abstinence from  all tobacco. Independently funded research on the effectiveness and safety of HTPs is needed.  The rate of decline in cigarette sales accelerated after the introduction of heated tobacco to market in Japan but, as data were observational, it is possible other factors caused these changes. Moreover, falls in cigarette sales may not translate to declining smoking prevalence, and changes in Japan may not generalise elsewhere. To clarify the impact of rising heated tobacco use on smoking prevalence, there is a need for time-series studies that examine this association.

E-cigarettes versus nicotine replacement treatment as harm reduction interventions for smokers who find quitting difficult: randomized controlled trial

BACKGROUND AND AIMS

The majority of smokers accessing the current best treatments continue to smoke. We aimed to test if e-cigarettes (EC) compared with nicotine replacement treatment (NRT) can help such smokers to reduce smoking.

DESIGN

Randomized controlled trial of EC (n = 68) versus NRT (n = 67) with 6-month follow-up.

SETTING

Stop smoking service in London, UK.

PARTICIPANTS

A total of 135 smokers (median age = 40 years, 51% male) previously unable to stop smoking with conventional treatments.

INTERVENTIONS

Participants received either NRT of their choice (8-week supply) or an EC starter pack and instructions to purchase further e-liquids of strength and flavours of their choice themselves. Products were accompanied by minimal behavioural support.

MEASUREMENTS

Participants who reported that they stopped smoking or reduced their daily cigarette consumption by at least 50% at 6-month follow-up were invited to provide a carbon monoxide (CO) reading. The primary outcome was biochemically validated reduction in smoke intake of at least 50% at 6 months and the main secondary outcome was sustained validated abstinence at 6 months. Drop-outs were included as 'non-reducers'.

FINDINGS

Validated smoking reduction (including cessation) was achieved by 26.5 versus 6.0% of participants in the EC and NRT study arms, respectively [relative risk (RR) = 4.4, P = 0.005, 95% confidence interval (CI) = 1.6-12.4]. Sustained validated abstinence rates at 6 months were 19.1 versus 3.0% (RR = 6.4, P = 0.01, 95% CI = 1.5-27.3). Product use was high and equal in both study arms initially, but at 6 months allocated product use was 47% in the EC arm versus 10% in the NRT arm (χ2(1)  = 22.0, P < 0.001), respectively. Adverse events were minor and infrequent.

CONCLUSIONS

In smokers unable to quit using conventional methods, e-cigarettes were more effective than nicotine replacement therapy in facilitating validated long-term smoking reduction and smoking cessation when limited other support was provided.

The Role of Dopamine D3 Receptors in Tobacco Use Disorder: A Synthesis of the Preclinical and Clinical Literature

Tobacco smoking is a significant cause of preventable morbidity and mortality globally. Current pharmacological approaches to treat tobacco use disorder (TUD) are only partly effective and novel approaches are needed. Dopamine has a well-established role in substance use disorders, including TUD, and there has been a long-standing interest in developing agents that target the dopaminergic system to treat substance use disorders. Dopamine has 5 receptor subtypes (DRD1 to DRD5). Given the localization and safety profile of the dopamine receptor D3 (DRD3), it is of therapeutic potential for TUD. In this chapter, the preclinical and clinical literature investigating the role of DRD3 in processes relevant to TUD will be reviewed, including in nicotine reinforcement, drug reinstatement, conditioned stimuli and cue-reactivity, executive function, and withdrawal. Similarities and differences in findings from the animal and human work will be synthesized and findings will be discussed in relation to the therapeutic potential of targeting DRD3 in TUD.

Short-Term Cardiovascular Effects of E-Cigarettes in Adults Making a Stop-Smoking Attempt: A Randomized Controlled Trial

Simple Summary

E-cigarettes are popular for smoking cessation but knowledge of their effect on cardiovascular health is limited. We compared the short-term cardiovascular effects in 248 smokers who quit smoking using e-cigarettes with or without nicotine or prescription nicotine replacement therapy (NRT). All participants received behavioural support. We assessed the cardiovascular effects of these stop smoking methods 3 days following quit date. Our work suggests that e-cigarettes offer similar vascular health benefits to that of NRT. This happens at a very early stage in the stop smoking process (3 days).

Abstract

Smoking increases cardiovascular disease (CVD) risk by leading to endothelial injury. E-cigarettes remain a popular way to stop smoking. Evidence on their effect on cardiovascular health is growing but remains limited, particularly in the short-term. The main objective of this study was to compare short-term cardiovascular effects in smokers who quit smoking using e-cigarettes with or without nicotine or prescription nicotine replacement therapy (NRT). This was a single-centre (Sheffield, UK) pragmatic three-arm randomised controlled trial which recruited adult smokers (≥10 cigarettes per day), who were willing to attempt to stop smoking with support (n = 248). Participants were randomised to receive either: (a) behavioral support and e-cigarettes with 18 mg/mL nicotine (n = 84); (b) behavioral support and e-cigarettes without nicotine (n = 82); (c) behavioral support and NRT (n = 82). Flow Mediated Dilation (%FMD), peak cutaneous vascular conductance responses to acetylcholine (ACh) and sodium nitroprusside (SNP) and mean arterial pressure (MAP) were recorded at baseline and three days after stopping smoking. General Linear Models were used to compare changes between groups and changes from follow-up. Adjusting for baseline, at follow-up, all outcomes (for the 208 participants that completed the 3-day assessments) with the exception of SNP had improved significantly over baseline and there were no differences between groups (%FMD F = 1.03, p = 0.360, df = 2,207; ACh F = 0.172, p = 0.84, df = 2,207; SNP F = 0.382, p = 0.68, df = 2,207; MAP F = 0.176, p = 0.84, df = 2,207). For smokers ≥20 cigarettes per day, benefits were also pronounced. Smoking cessation showed positive cardiovascular impact even after a 3-day period and the effects did not differ between nicotine-containing e-cigarettes, nicotine-free e-cigarettes and NRT.

Supporting smoking cessation and preventing relapse following a stay in a smoke-free setting: a meta-analysis and investigation of effective behaviour change techniques

BACKGROUND AND AIMS

Admission to a smoke-free setting presents a unique opportunity to encourage smokers to quit. However, risk of relapse post-discharge is high, and little is known about effective strategies to support smoking cessation following discharge. We aimed to identify interventions that maintain abstinence following a smoke-free stay and determine their effectiveness, as well as the probable effectiveness of behaviour change techniques (BCTs) used in these interventions.

METHODS

Systematic review and meta-analyses of studies of adult smokers aged ≥ 18 years who were temporarily or fully abstinent from smoking to comply with institutional smoke-free policies. Institutions included prison, inpatient mental health, substance misuse or acute hospital settings. A Mantel-Haenszel random-effects meta-analysis of randomized controlled trials (RCTs) was conducted using biochemically verified abstinence (7-day point prevalence or continuous abstinence). BCTs were defined as 'promising' in terms of probable effectiveness (if BCT was present in two or more long-term effective interventions) and feasibility (if BCT was also delivered in ≥ 25% of all interventions).

RESULTS

Thirty-seven studies (intervention n = 9041, control n = 6195) were included: 23 RCTs (intervention n = 6593, control n = 5801); three non-randomized trials (intervention n = 845, control n = 394) and 11 cohort studies (n = 1603). Meta-analysis of biochemically verified abstinence at longest follow-up (4 weeks-18 months) found an overall effect in favour of intervention [risk ratio (RR) = 1.27, 95% confidence interval (CI) = 1.08-1.49, I²  = 42%]. Nine BCTs (including 'pharmacological support', 'goal-setting (behaviour)' and 'social support') were characterized as 'promising' in terms of probable effectiveness and feasibility.

CONCLUSIONS

A systematic review and meta-analyses indicate that behavioural and pharmacological support is effective in maintaining smoking abstinence following a stay in a smoke-free institution. Several behaviour change techniques may help to maintain smoking abstinence up to 18 months post-discharge.

Facebook Chat Application to Prompt and Assist Smoking Cessation Among Spanish-Speaking Young Adults in South Texas

Given how smart phones, internet services, and social media have shown great potential for assisting smoking cessation, we constructed a Facebook chat application based on our previous work with SMS texting services. This report summarizes findings from 2,364 Spanish-speaking young adults recruited through Facebook advertising in South Texas during the 2020 New Year holiday season. Among these service users, 926 (39%) were ready to make a quit attempt, and 26 (3.1%) of those users reported that they were tobacco free 1 month later. There were no responses to a chat question survey 72 days after the dates selected for quitting. Although more research with longer follow up is needed, these findings show that social media chat applications may be helpful for at least prompting quit attempts and short-term cessation among young adult Spanish-speaking smokers. There is no evidence of an impact on long-term cessation, and more research is clearly needed.

Effectiveness of Non-Nicotinic E-Cigarettes to Reduce Cue- and Abstinence-Induced Cigarette Craving in Non-Treatment Seeking Daily Dependent Smokers

RATIONALE

Electronic cigarettes (e-cigarettes) are potential tools for smoking cessation because they deliver nicotine and simulate smoking behaviors. The contribution of sensorimotor versus pharmacological substitution is unknown.

OBJECTIVES

To evaluate whether non-nicotinic e-cigarettes, used alone or with nicotine lozenges, can attenuate cigarette craving following visual cue presentation or acute (3 h post ad-lib use) abstinence in dependent daily smokers.

METHODS

Following overnight (12 hours) abstinence, 41 daily smokers were exposed to 4 experimental conditions on separate days: (i) tobacco cigarettes (CIG); (ii) non-nicotinic e-cigarettes with placebo lozenges (EPL); (iii) non-nicotinic e-cigarettes with 4 mg nicotine lozenge (ENL); and (iv) 4 mg nicotine lozenge (NL). Cigarette craving was assessed following presentation of neutral and smoking cues at various time points using the Brief Questionnaire of Smoking Urges (QSU-B) and visual analog scales (VAS).

RESULTS

All experimental conditions significantly reduced participants' baseline overnight abstinence cigarette craving. ENLs and NLs attenuated smoking-cue-induced cravings to a greater extent than CIGs, where cravings were significantly higher with CIGs compared to ENLs [mean difference (MD) ± standard error (SE) in QSU-B = 3.2 ± 0.84, P = 0.002; VAS = 12.7 ± 2.7, P < 0.0005] and NLs [MD ± SE in QSU-B = 2.7 ± 0.92, P = 0.031; VAS = 8.1 ± 2.3, P = 0.005]. Craving responses to cues after 3 h were higher after smoking CIGs compared to ENLs [MD ± SE in QSU-B = 3.9 ± 1.4, P = 0.047; VAS = 14.1 ± 3.6, P = 0.002] and NLs [MD ± SE in QSU-B = 3.2 ± 1.1, P = 0.046; VAS = 9.7 ± 3.1, P = 0.017].

CONCLUSIONS

Behavioral simulation of smoking with or without nicotine reduces nicotine craving. Compared to cigarettes, ENL with NL or NL alone attenuates cigarette craving over time. Future clinical trials should evaluate the combination of ENL and NL as a method for smoking reduction or cessation.

TRIAL REGISTRATION

NCT02108626.

Impact of CYP2A6 Activity on Nicotine Reinforcement and Cue-Reactivity in Daily Smokers

INTRODUCTION

Variation in CYP2A6, the primary enzyme responsible for nicotine metabolism, is associated with nicotine dependence, cigarette consumption, and abstinence outcomes in smokers. The impact of CYP2A6 activity on nicotine reinforcement and tobacco cue-reactivity, mechanisms that may contribute to these previous associations, has not been fully evaluated.

AIMS AND METHODS

CYP2A6 activity was indexed using 3 genetic approaches in 104 daily smokers completing forced-choice and cue-induced craving tasks assessing nicotine reinforcement and tobacco cue-reactivity, respectively. First, smokers were stratified by the presence or absence of reduced/loss-of-function CYP2A6 gene variants (normal vs. reduced metabolizers). As nicotine metabolite ratio (NMR) is a reliable biomarker of CYP2A6 activity, our second and third approaches used additional genetic variants identified in genome-wide association studies of NMR to create a weighted genetic risk score (wGRS) to stratify smokers (fast vs. slow metabolizers) and calculate a wGRS-derived NMR.

RESULTS

Controlling for race and sex, normal metabolizers (vs. reduced) selected a greater proportion of puffs from nicotine-containing cigarettes (vs. denicotinized) on the forced-choice task (p = .031). In confirmatory analyses, wGRS-based stratification (fast vs. slow metabolizers) produced similar findings. Additionally, wGRS-derived NMR, which correlated with actual NMR assessed in a subset of participants (n = 55), was positively associated with the proportion of puffs from nicotine-containing cigarettes controlling for race and sex (p = .015). None of the CYP2A6 indices were associated with tobacco cue-reactivity in minimally deprived smokers.

CONCLUSIONS

Findings suggest increased nicotine reinforcement is exhibited by smokers with high CYP2A6 activity, which may contribute to heavier smoking and poorer cessation outcomes previously reported in faster metabolizers.

IMPLICATIONS

CYP2A6 activity is a key determinant of smoking behavior and outcomes. Therefore, these findings support the targeting of CYP2A6 activity, either therapeutically or as a clinically relevant biomarker in a precision medicine approach, for tobacco use disorder treatment.

Significant association of nicotine reinforcement and cue reactivity: a translational study in humans and rats

Relapse is common amongst smokers attempting to quit and tobacco cue-induced craving is an important relapse mechanism. Preclinical studies commonly use cue-induced reinstatement of nicotine seeking to investigate relapse neurobiology. Previous research suggests dependence severity and nicotine intake history affect smoking resumption and cue-induced reinstatement of nicotine seeking. However, behavioural data may be interpreted in terms of nicotine reinforcement. This translational study investigated if individual differences in objectively assessed nicotine reinforcement strength were associated with cue-reactivity in both rats and human smokers, which to our knowledge has not been investigated before. Rats (n = 16) were trained to self-administer nicotine and were tested on a progressive ratio schedule of nicotine reinforcement, to assess reinforcer strength, and on a test of cue-induced reinstatement of nicotine seeking. Nicotine reinforcement strength was assessed in human smokers (n = 104) using a forced choice task (nicotine containing vs. denicotinised cigarettes) and self-reported cue-induced craving was assessed following exposure to smoking and neutral cues. Responding for nicotine under progressive ratio was strongly positively correlated with cue-induced reinstatement of nicotine seeking in rats. Nicotine choices in human smokers were significantly associated with cue-induced craving controlling for dependence severity, years of smoking, and urge to smoke following neutral cues. Findings suggest nicotine reinforcement strength is associated with both types of cue-induced behaviour, implying some translational commonality between cue-induced craving in human smokers and cue-induced reinstatement of nicotine seeking in rats. Findings are discussed in relation to clinical implications and whether these laboratory tasks assess drug 'wanting'.

Protocol for expansion of an existing national monthly survey of smoking behaviour and alcohol use in England to Scotland and Wales: The Smoking and Alcohol Toolkit Study

Background The Smoking and Alcohol Toolkit Study (STS/ATS) in England has delivered timely insights to inform and evaluate strategies aimed at reducing tobacco smoking- and alcohol-related harm. From the end of 2020 until at least 2024 the STS/ATS is expanding to Scotland and Wales to include all constituent nations in Great Britain. Expanding data collection to Scotland and Wales will permit the evaluation of how smoking and alcohol related behaviours respond to divergent policy scenarios across the devolved nations. Methods The STS/ATS consists of monthly cross-sectional household interviews (computer or telephone assisted) of representative samples of adults in Great Britain aged 16+ years. Commencing in October 2020 each month a new sample of approximately 1700 adults in England, 450 adults in Scotland and 300 adults in Wales complete the survey (~n = 29,400 per year). The expansion of the survey to Scotland and Wales has been funded for the collection of at least 48 waves of data across four years. The data collected cover a broad range of smoking and alcohol-related parameters (including but not limited to smoking status, cigarette/nicotine dependence, route to quit smoking, prevalence and frequency of hazardous drinking, attempts and motivation to reduce alcohol consumption, help sought and motives for attempts to reduce alcohol intake) and socio-demographic characteristics (including but not limited to age, gender, region, socio-economic position) and will be reviewed monthly and refined in response to evolving policy needs and public interests. All data analyses will be pre-specified and available on a free online platform. A dedicated website will publish descriptive data on important trends each month. Discussion The Smoking and Alcohol Toolkit Study will provide timely monitoring of smoking and alcohol related behaviours to inform and evaluate national policies across Great Britain.

The efficacy and safety of varenicline alone versus in combination with nicotine lozenges for smoking cessation among hospitalised smokers (VANISH): study protocol for a randomised, placebo-controlled trial

INTRODUCTION

Smoking is a leading cause of premature deaths globally. The health benefits of smoking cessation are many. However, majority of quit attempts are unsuccessful. One way to potentially improve success rates is to evaluate new combinations of existing smoking cessation therapies that may work synergistically to decrease the intensity of withdrawal symptoms and cravings.

AIMS

To evaluate the feasibility, efficacy and safety of the combination of varenicline and nicotine replacement therapy (NRT) lozenges versus varenicline alone in assisting hospitalised smokers to quit.

METHODS AND ANALYSIS

This is a multicentre, randomised, placebo-controlled trial. Adults with a history of smoking ≥10 cigarettes per day on average in the 4 weeks prior to their hospitalisation will be recruited. Participants will be randomly assigned to either the intervention group and will receive varenicline and NRT lozenges, or the control group and will receive varenicline and placebo lozenges. All participants will be actively referred to behavioural support from telephone Quitline. Participants are followed up at 1 and 3 weeks and 3, 6 and 12 months from the start of treatment. The primary outcome is carbon monoxide validated prolonged abstinence from 2 weeks to 6 months after treatment initiation. Secondary outcomes include self-reported and biochemically validated prolonged and point prevalence abstinence at 3, 6 and 12 months, self-reported adverse events, withdrawal symptoms and cravings, adherence to treatment, Quitline sessions attended and others. According to the Russell Standard, all randomised participants will be accounted for in the primary intention-to-treat analysis.

ETHICS AND DISSEMINATION

The trial will be conducted in compliance with the protocol, the principles of Good Clinical Practice, the National Health and Medical Research Council National Statement on Ethical Conduct in Human Research (updated 2015) and the Australian Code for the Responsible Conduct of Research (2018). Approval will be sought from the Human Ethics Committees of all the participating hospitals and the university. Written informed consent will be obtained from each participant at the time of recruitment.

TRIAL REGISTRATION NUMBER

Australia New Zealand Clinical Trials Registry (ACTRN12618001792213).

Effectiveness of WhatsApp online group discussion for smoking relapse prevention: protocol for a pragmatic randomized controlled trial

BACKGROUND AND AIMS

Sustained psychosocial support via online social groups may help former tobacco users maintain abstinence. This study aims to examine the effectiveness of participating in a WhatsApp social group for long-term smoking cessation.

DESIGN

Two-arm, open-labelled, pragmatic, individually randomized controlled trial.

SETTING

All participants are service users of smoking cessation clinics, and all interventions are delivered via mobile phones.

PARTICIPANTS

Participants included 1008 adult quitters who self-report no tobacco use in the past 3-30 days.

INTERVENTIONS

The intervention group (n = 504) will join a WhatsApp social group to receive standardized and theory-based reminders of smoking relapse prevention and participate in discussion with other WhatsApp group members using their own mobile phones. All social groups will be led by counselors or specialist nurse practitioners. The control group (n = 504) will receive similar reminders via short messages to their own mobile phones but will not interact with other participants. The intervention duration for both groups is 8 weeks. Both groups will receive a booklet at baseline about how to prevent smoking relapse.

MEASUREMENTS

The primary outcome is biochemically validated tobacco abstinence at 12 months after consent.

COMMENTS

The findings will provide evidence concerning the utility of operating online social group discussion for prevention of smoking relapse and sustaining long-term abstinence.

Influence of the SARS-CoV-2 Outbreak on the Uptake of a Popular Smoking Cessation App in UK Smokers: Interrupted Time Series Analysis

BACKGROUND

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak may motivate smokers to attempt to stop in greater numbers. However, given the temporary closure of UK stop smoking services and vape shops, smokers attempting to quit may instead seek out mobile health support, such as smartphone apps.

OBJECTIVE

We examined, using an interrupted time series approach, whether the SARS-CoV-2 outbreak has been associated with a step change or increasing trend in UK downloads of an otherwise popular smoking cessation app, Smoke Free.

METHODS

Data were from daily and nondaily adult smokers in the United Kingdom who had downloaded the Smoke Free app between January 1, 2020, and March 31, 2020 (primary analysis), and January 1, 2019, and March 31, 2020 (secondary analysis). The outcome variable was the number of downloads aggregated at the 12-hourly (primary analysis) or daily level (secondary analysis). The explanatory variable was the start of the SARS-CoV-2 outbreak, operationalized as March 1, 2020 (primary analysis), and January 15, 2020 (secondary analysis). Generalized additive mixed models adjusted for relevant covariates were fitted.

RESULTS

Data were collected on 45,105 (primary analysis) and 119,881 (secondary analysis) users. In both analyses, there was no evidence for a step change or increasing trend in downloads attributable to the start of the SARS-CoV-2 outbreak. Calculation of Bayes factors (BFs) indicated that the data for the primary analysis favored the null hypothesis compared with large associations (for level, BF=0.25; for slope, BF=0.26) but were insensitive to the detection of small associations (for level, BF=0.78; for slope, BF=1.35).

CONCLUSIONS

In the United Kingdom, between January 1, 2020, and March 31, 2020, and between January 1, 2019, and March 31, 2020, there was no evidence that the SARS-CoV-2 outbreak has been associated with a large step change or increasing trend in downloads of a popular smoking cessation app. Findings on the association of the SARS-CoV-2 outbreak with a small step change or increasing trend were inconclusive.

Socioeconomic differences in the motivation to stop using e-cigarettes and attempts to do so

Introduction

In England, the use of electronic cigarettes as a smoking cessation aid has become more popular than any other aid. Previous research suggests that ex-smokers from lower social groups are more likely to use e-cigarettes compared to ex-smokers from more socially advantaged groups. The present study aimed to assess the association between baseline education, income and employment status and (1) baseline motivation to stop using e-cigarettes (2) attempts to stop using e-cigarettes during follow-up among current smokers, recent ex-smokers and long-term ex-smokers who use e-cigarettes.

Methods

UK online longitudinal survey of smokers, ex-smokers and e-cigarette users, May/June 2016 (baseline) and September 2017 (follow-up). In logistic regression models, motivation to stop using e-cigarettes at baseline (n = 994) and attempts to stop using e-cigarettes at follow-up (n = 416) among current smokers and ex-smokers were regressed onto baseline educational attainment, income, employment status while adjusting for baseline demographics, vaping status, smoking and e-cigarette dependence.

Results

(1) Respondents with higher education (OR = 1.36; 95% CI: 1.06-1.74) or higher income (OR = 1.52; 95% CI: 1.17-1.98) were more likely to be motivated to stop using e-cigarettes, but only in unadjusted analysis. (2) Again, in unadjusted analysis only, employment was associated with reduced odds of attempting to stop using e-cigarette (OR = 0.50; 95% CI: 0.32-0.79).

Conclusion

Higher socio-economic status may be associated with higher motivation to stop vaping but with lower likelihood of trying to do so.

Associations between vaping and relapse to smoking: preliminary findings from a longitudinal survey in the UK

BACKGROUND

Most smokers attempting to quit relapse. There is little evidence whether the use of e-cigarettes ('vaping') increases or decreases relapse. This study aimed to assess 1) whether vaping predicted relapse among ex-smokers, and 2) among ex-smokers who vaped, whether vaping characteristics predicted relapse.

METHODS

Longitudinal web-based survey of smokers, recent ex-smokers and vapers in the UK, baseline in May/June 2016 (n = 3334), follow-up in September 2017 (n = 1720). Those abstinent from smoking ≥ 2 months at baseline and followed up were included. Aim 1: Relapse during follow-up was regressed onto baseline vaping status, age, gender, income, nicotine replacement therapy use and time quit smoking (n = 374). Aim 2: Relapse was regressed onto baseline vaping frequency, device type, nicotine strength and time quit smoking (n = 159).

RESULTS

Overall, 39.6% relapsed. Compared with never use (35.9%), past/ever (45.9%; adjOR = 1.13; 95% CI, 0.61-2.07) and daily vaping (34.5%; adjOR = 0.61; 95% CI, 0.61-1.89) had similar odds of relapse, for non-daily vaping evidence of increased relapse was inconclusive (65.0%; adjOR = 2.45; 95% CI, 0.85-7.08). Among vapers, non-daily vaping was associated with higher relapse than daily vaping (adjOR = 3.88; 95% CI, 1.10-13.62). Compared with modular devices (18.9% relapse), tank models (45.6%; adjOR = 3.63; 95% CI, 1.33-9.95) were associated with increased relapse; evidence was unclear for disposable/cartridge refillable devices (41.9%; adjOR = 2.83; 95% CI, 0.90-8.95). Nicotine strength had no clear association with relapse.

CONCLUSION

Relapse to smoking is likely to be more common among ex-smokers vaping infrequently or using less advanced devices. Research into the effects of vaping on relapse needs to consider vaping characteristics.

Modelling continuous abstinence rates over time from clinical trials of pharmacological interventions for smoking cessation

BACKGROUND AND AIM

It is useful, for theoretical and practical reasons, to be able to specify functions for continuous abstinence over time in smoking cessation attempts. This study aimed to find the best-fitting models of mean proportion abstinent with different smoking cessation pharmacotherapies up to 52 weeks from the quit date.

METHODS

We searched the Cochrane Database of Systematic Reviews to identify randomized controlled trials (RCTs) of pharmacological treatments to aid smoking cessation. For comparability, we selected trials that provided 12 weeks of treatment. Continuous abstinence rates for each treatment at each follow-up point in trials were extracted along with methodological details of the trial. Data points for each pharmacotherapy at each follow-up point were aggregated where the total across contributing studies included at least 1000 participants per data point. Continuous abstinence curves were modelled using a range of different functions from the quit date to 52-week follow-up. Models were compared for fit using R2 and Bayesian information criterion (BIC).

RESULTS

Studies meeting our selection criteria covered three pharmacotherapies [varenicline, nicotine replacement therapy (NRT) and bupropion] and placebo. Power functions provided the best fit (R2  > 0.99, BIC < 17.0) to continuous abstinence curves from the target quit date in all cases except for varenicline, where a logarithmic function described the curve best (R2  = 0.99, BIC = 21.2). At 52 weeks, abstinence rates were 22.5% (23.0% modelled) for varenicline, 16.7% (16.0% modelled) for bupropion, 13.0% (12.4% modelled) for NRT and 8.3% (8.9% modelled) for placebo. For varenicline, bupropion, NRT and placebo, respectively, 55.9, 65.0, 62.3 and 56.5% of participants who were abstinent at the end of treatment were still abstinent at 52 weeks.

CONCLUSIONS

Mean continuous abstinence rates up to 52 weeks from initiation of smoking cessation attempts in clinical trials can be modelled using simple power functions for placebo, nicotine replacement therapy and bupropion and a logarithmic function for varenicline. This allows accurate prediction of abstinence rates from any time point to any other time point up to 52 weeks.

Relative effectiveness of a full versus reduced version of the 'Smoke Free' mobile application for smoking cessation: an exploratory randomised controlled trial

Background: Smartphone applications (apps) are popular aids for smoking cessation. Smoke Free is an app that delivers behaviour change techniques used in effective face-to-face behavioural support programmes. The aim of this study was to assess whether the full version of Smoke Free is more effective than the reduced version. Methods:  This was a two-arm exploratory randomised controlled trial. Smokers who downloaded Smoke Free were randomly offered the full or reduced version; 28,112 smokers aged 18+ years who set a quit date were included. The full version provided updates on benefits of abstinence, progress (days smoke free), virtual 'badges' and daily 'missions' with push notifications aimed at preventing and managing cravings. The reduced version did not include the missions. At baseline the app recorded users': device type (iPhone or Android), age, sex, daily cigarette consumption, time to first cigarette of the day, and educational level. The primary outcome was self-reported complete abstinence from the quit date in a 3-month follow-up questionnaire delivered via the app. Analyses conducted included logistic regressions of outcome on to app version (full versus reduced) with adjustment for baseline variables using both intention-to-treat/missing-equals smoking (MES) and follow-up-only (FUO) analyses. Results: The 3-month follow-up rate was 8.5% (n=1,213) for the intervention and 6.5% (n=901) for the control. A total of 234 participants reported not smoking in the intervention versus 124 in the control, representing 1.6% versus 0.9% in the MES analysis and 19.3% versus 13.8% in the FUO analysis. Adjusted odds ratios were 1.90, 95%CI=1.53-2.37 (p<0.001) and 1.50, 95%CI=1.18-1.91 (p<0.001) in the MES and FUO analyses respectively. Conclusions: Despite very low follow-up rates using in-app follow up, both intention-to-treat/missing equals smoking and follow-up only analyses showed the full version of the Smoke Free app to result in higher self-reported 3-month continuous smoking abstinence rates than the reduced version.

Relative effectiveness of a full versus reduced version of the 'Smoke Free' mobile application for smoking cessation: a randomised controlled trial

Background: Smartphone applications (apps) are popular aids for smoking cessation. Smoke Free is an app that delivers behaviour change techniques used in effective face-to-face behavioural support programmes. The aim of this study was to assess whether the full version of Smoke Free is more effective than the reduced version. Methods:  This was a two-arm randomised controlled trial. Smokers who downloaded Smoke Free were randomly offered the full or reduced version; 28,112 smokers aged 18+ years who set a quit date were included. The full version provided updates on benefits of abstinence, progress (days smoke free), virtual 'badges' and daily 'missions' with push notifications aimed at preventing and managing cravings. The reduced version did not include the missions. At baseline the app recorded users': device type (iPhone or Android), age, sex, daily cigarette consumption, time to first cigarette of the day, and educational level. The primary outcome was self-reported complete abstinence from the quit date in a 3-month follow-up questionnaire delivered via the app. Analyses conducted included logistic regressions of outcome on to app version (full versus reduced) with adjustment for baseline variables using both intention-to-treat/missing-equals smoking (MES) and follow-up-only (FUO) analyses. Results: The 3-month follow-up rate was 8.5% (n=1,213) for the intervention and 6.5% (n=901) for the control. A total of 234 participants reported not smoking in the intervention versus 124 in the control, representing 1.6% versus 0.9% in the MES analysis and 19.3% versus 13.8% in the FUO analysis. Adjusted odds ratios were 1.90, 95%CI=1.53-2.37 (p<0.001) and 1.50, 95%CI=1.18-1.91 (p<0.001) in the MES and FUO analyses respectively. Conclusions: Despite very low follow-up rates using in-app follow up, both intention-to-treat/missing equals smoking and follow-up only analyses showed the full version of the Smoke Free app to result in higher self-reported 3-month continuous smoking abstinence rates than the reduced version.