Interventions to prevent or cease electronic cigarette use in children and adolescents

Abstract

Background

The prevalence of e‐cigarette use has increased globally amongst children and adolescents in recent years. In response to the increasing prevalence and emerging evidence about the potential harms of e‐cigarettes in children and adolescents, leading public health organisations have called for approaches to address increasing e‐cigarette use. Whilst evaluations of approaches to reduce uptake and use regularly appear in the literature, the collective long‐term benefit of these is currently unclear.

Objectives

The co‐primary objectives of the review were to: (1) evaluate the effectiveness of interventions to prevent e‐cigarette use in children and adolescents (aged 19 years and younger) with no prior use, relative to no intervention, waitlist control, usual practice, or an alternative intervention; and (2) evaluate the effectiveness of interventions to cease e‐cigarette use in children and adolescents (aged 19 years and younger) reporting current use, relative to no intervention, waitlist control, usual practice, or an alternative intervention. Secondary objectives were to: (1) examine the effect of such interventions on child and adolescent use of other tobacco products (e.g. cigarettes, cigars types, and chewing tobacco); and (2) describe the unintended adverse effects of the intervention on individuals (e.g. physical or mental health of individuals), or on organisations (e.g. intervention displacement of key curricula or learning opportunities for school students) where such interventions are being implemented.

Search methods

We searched CENTRAL, Ovid MEDLINE, Ovid Embase, Ovid PsycINFO, EBSCO CINAHL, and Clarivate Web of Science Core Collection from inception to 1 May 2023. Additionally, we searched two trial registry platforms (WHO International Clinical Trials Registry Platform; US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov), Google Scholar, and the reference lists of relevant systematic reviews. We contacted corresponding authors of articles identified as ongoing studies.

Selection criteria

We included randomised controlled trials (RCTs), including cluster‐RCTs, factorial RCTs, and stepped‐wedge RCTs. To be eligible, the primary targets of the interventions must have been children and adolescents aged 19 years or younger. Interventions could have been conducted in any setting, including community, school, health services, or the home, and must have sought to influence children or adolescent (or both) e‐cigarette use directly. Studies with a comparator of no intervention (i.e. control), waitlist control, usual practice, or an alternative intervention not targeting e‐cigarette use were eligible. We included measures to assess the effectiveness of interventions to: prevent child and adolescent e‐cigarette use (including measures of e‐cigarette use amongst those who were never‐users); and cease e‐cigarette use (including measures of e‐cigarette use amongst children and adolescents who were e‐cigarette current‐users). Measures of e‐cigarette use included current‐use (defined as use in the past 30 days) and ever‐use (defined as any lifetime use).

Data collection and analysis

Two review authors independently screened the titles and abstracts of references, with any discrepancies resolved through consensus. Pairs of review authors independently assessed the full‐text articles for inclusion in the review. We planned for two review authors to independently extract information from the included studies and assess risk of bias using the Cochrane RoB 2 tool. We planned to conduct multiple meta‐analyses using a random‐effects model to align with the co‐primary objectives of the review. First, we planned to pool interventions to prevent child and adolescent e‐cigarette use and conduct two analyses using the outcome measures of 'ever‐use' and 'current‐use'. Second, we planned to pool interventions to cease child and adolescent e‐cigarette use and conduct one analysis using the outcome measure of 'current‐use'. Where data were unsuitable for pooling in meta‐analyses, we planned to conduct a narrative synthesis using vote‐counting approaches and to follow the Cochrane Handbook for Systematic Reviews of Interventions and the Synthesis Without Meta‐analysis (SWiM) guidelines.

Main results

The search of electronic databases identified 7141 citations, with a further 287 records identified from the search of trial registries and Google Scholar. Of the 110 studies (116 records) evaluated in full text, we considered 88 to be ineligible for inclusion for the following reasons: inappropriate outcome (27 studies); intervention (12 studies); study design (31 studies); and participants (18 studies). The remaining 22 studies (28 records) were identified as ongoing studies that may be eligible for inclusion in a future review update. We identified no studies with published data that were eligible for inclusion in the review.

Authors' conclusions

We identified no RCTs that met the inclusion criteria for the review, and as such, there is no evidence available from RCTs to assess the potential impact of interventions targeting children and adolescent e‐cigarette use, tobacco use, or any unintended adverse effects. Evidence from studies employing other trial designs (e.g. non‐randomised) may exist; however, such studies were not eligible for inclusion in the review. Evidence from studies using non‐randomised designs should be examined to guide actions to prevent or cease e‐cigarette use.

This is a living systematic review. We search for new evidence every month and update the review when we identify relevant new evidence. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

Plain language summary

Do interventions to stop children and adolescents from using electronic cigarettes work?

Key messages

There are currently no published randomised controlled trials assessing the impact of interventions to prevent or stop e‐cigarette use amongst children and adolescents. We did, however, find 22 of these types of studies underway that appear to be eligible for future updates to this review, which may provide more answers.

What did we want to find out?

We wanted to find out how effective interventions were in either preventing or ceasing (i.e. stopping) child and/or adolescent e‐cigarette use. We also wanted to know what the effect of these interventions was on child and/or adolescent use of tobacco, and if the interventions had any consequences related to the health of children and/or adolescents, or the organisations where the interventions were being delivered.

What did we do?

We searched for all available evidence from randomised controlled trials (a type of study where participants are randomly assigned to one of two or more treatment groups) to answer the review questions.

What did we find?

We searched for studies on 1 May 2023 and found no published studies. However, we did find 22 studies that were underway and will probably be included in future updates of the review. Given that we found no studies for inclusion, we do not know how effective interventions are in preventing or ceasing child and/or adolescent e‐cigarette use.

How up‐to‐date is this evidence?

This evidence is current to 1 May 2023.

This is a living systematic review. We search for new evidence every month and update the review when we identify relevant new evidence. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

Background

Description of the condition

Electronic nicotine delivery systems (ENDS) and electronic non‐nicotine delivery systems (ENNDS) heat a liquid to produce an aerosol to inhale (often known as ‘vaping’). The e‐liquids typically contain propylene glycol, vegetable glycerine/glycerol, flavour additives, known toxic chemicals and, commonly, nicotine (i.e. ENDS) (NHMRC 2022; WHO 2019). ENDS and ENNDS come in various forms including e‐cigarettes, e‐hookahs, e‐cigars, and e‐pipes, with e‐cigarettes being the most common (WHO 2020).

Initially marketed as a smoking cessation aid in the mid‐2000s, the use of e‐cigarettes has increased globally amongst adults, children, and adolescents (WHO 2020). A systematic review synthesising the prevalence of e‐cigarette use in children and adolescents (aged 8 to 20 years) from 69 countries and territories reported a pooled prevalence for ever‐use (defined as any lifetime use) of 17.2% and current‐use (defined as use in the past 30 days) of 7.8% (Yoong 2021a). Of growing concern is the high prevalence of e‐cigarette use amongst adolescents who are otherwise not current or ever‐users of tobacco. For example, in one Australian survey of adolescents aged 14 to 17 years, 14% of adolescents reported e‐cigarette ever‐use (32% of these in the past month), almost half (48%) of whom had never smoked tobacco (Guerin 2020). The increasing use of e‐cigarettes is likely influenced by a number of complex interpersonal (e.g. lower perceived risks and harms regarding e‐cigarette use) (Amrock 2015), societal (e.g. peer and sibling influences) (Durkin 2021; Fite 2019), and environmental (e.g. accessibility and exposure to e‐cigarette‐related marketing) factors (D'Angelo 2021). 

There remains debate as to whether the introduction of e‐cigarettes has facilitated the decline in tobacco smoking, and if their benefit as a smoking cessation aid for established adult smokers outweighs their potential risk of increasing e‐cigarette and tobacco use in children and adolescents (Greenhalgh 2021). Findings from one Cochrane living systematic review reported moderate‐certainty evidence that nicotine containing e‐cigarettes do increase quit rates compared to nicotine replacement therapy in adult smokers (Hartmann‐Boyce 2021). Further, in several countries, increases in e‐cigarette use amongst adolescents have been accompanied by declines in adolescent cigarette smoking  (WHO (Europe) 2020), suggesting that e‐cigarette use may have contributed to this reduction. However, meta‐analyses of prospective cohort studies report that e‐cigarette use is independently associated with increased risk of initiating cigarette smoking (Khouja 2021; Yoong 2021b), as well as increased inflammatory responses and harmful effects on respiratory outcomes (Fadus 2019). Additionally, one systematic review of global evidence concluded that the use of nicotine‐containing e‐cigarettes (i.e. ENDS) as well as e‐cigarettes marketed as nicotine‐free (i.e. ENNDS) poses serious adverse effects to users (Banks 2022). These potential harms include acute lung injury known as EVALI (e‐cigarette or vaping product use‐associated lung injury), poisoning, burns, immediate toxicity through inhalation, and seizures (Banks 2022). Less serious adverse effects include nausea and throat irritation (Banks 2022). Specifically for children and adolescents, systematic review evidence indicates the use of e‐cigarettes is significantly associated with respiratory conditions, including asthma (Li 2022). Further, the potential risk to brain development, attention, and learning in adolescents as a result of consuming nicotine, which is commonly found in e‐cigarettes, is of particular concern (Benowitz 2021; Bonner 2021)

Description of the intervention

In response to emerging evidence about the potential harmful health effects of e‐cigarettes on children and adolescents and the lack of benefits for non‐smoking youths, leading public health organisations including the World Health Organization (WHO) have developed recommendations to address this potential public health issue (WHO 2019). For example, the WHO Framework Convention on Tobacco Control (FCTC) developed core demand reduction provisions, including price, tax, and non‐price measures to reduce the demand for tobacco (WHO 2003), which have been applied to e‐cigarettes (WHO 2021). These provisions are part of the MPOWER measures, a set of six cost‐effective and high‐impact measures introduced by WHO to assist in the country‐level implementation of effective interventions to reduce the demand for tobacco (WHO 2022). The six measures include: monitoring tobacco use and prevention policies; protecting people from tobacco smoke; offering help to quit tobacco use; warning about the dangers of tobacco; enforcing bans on tobacco advertising, promotion, and sponsorship; and raising taxes on tobacco. Non‐price measures include the packaging and labelling of tobacco products, and education, communication, training, and public awareness (WHO 2003).

In response to the MPOWER measures introduced by WHO, several countries have implemented national and state‐level policy and legislative changes to restrict the supply of e‐cigarettes to children and adolescents (WHO 2019). For example, the United States passed federal legislation in 2019 which prohibits the sale of all tobacco products, including e‐cigarettes, to individuals under 21 years of age. In Australia, in addition to state‐level restrictions on underage sales of e‐cigarettes that were introduced over the past decade (NSW Legislation 2015), Australia recently passed national legislation requiring a prescription for all individuals over the age of 18 years wishing to access nicotine‐containing e‐cigarettes (TGA 2021). To address the MPOWER non‐price measures, national health agencies have recommended the development of education, communication, training, and health promotion programmes targeting children and adolescents to prevent or cease (or both) e‐cigarette use (CDC 2016; SAMHSA 2020). For example, the US Substance Abuse and Mental Health Services Administration has produced an evidence‐based resource guide to translate e‐cigarette research into recommendations for practice, and provide examples of how to implement these recommendations via individual, education, and community‐level interventions (SAMHSA 2020). In recent years, various health promotion programmes have been developed and delivered through different settings to prevent and/or cease e‐cigarette use in children and adolescents (Gaiha 2021; Graham 2021; Hieftje 2021; Huang 2017; Kelder 2020; Vallone 2017). Evaluation of public and community‐based interventions, delivered via social media, text messages, and online modalities, suggests that these approaches are potentially effective in reducing adolescent e‐cigarette use and increasing abstinence rates (Graham 2021; Hieftje 2021; Huang 2017; Vallone 2017). School‐based programmes targeting school policy and curriculum changes regarding the use of e‐cigarettes in schools, in combination with targeting students via social media and online programmes, have shown promise in increasing adolescent knowledge of the potential harms and reducing adolescent intent to try e‐cigarettes (Gaiha 2021; Kelder 2020). Although early non‐controlled evidence suggests such programmes may be beneficial, few rigorous evaluations have been conducted.

How the intervention might work

Several theories have been used to describe how the proposed interventions may work to influence child and adolescent health behaviours (Institute of Medicine 2001). However, given that child and adolescent e‐cigarette use is a relatively new public health issue, theories to describe how interventions may work to specifically influence child and adolescent e‐cigarette use are scarce. Nonetheless, multiple psychosocial theories, including the theory of planned behaviour (Topa 2010), socio‐ecological model (Aghdam 2021), and social cognitive theory (Thomas 2015), have been previously used to describe potential causal pathways to child and adolescent tobacco use, and may also be relevant for behaviour related to the initiation and use of e‐cigarettes.

Collectively, these theories suggest that an individual's behaviour is influenced by a combination of personal and environmental factors, and that an individual's behaviour is directly related to the context of social interactions and experiences (Aghdam 2021; Thomas 2015; Topa 2010). As such, strategies effective in influencing child and adolescent cigarette use are likely to target both the individual's personal influences (e.g. knowledge, self‐efficacy) as well as their parents and carers (as key social influences) and environmental characteristics (such as friendship groups and perceived social norms) (Aghdam 2021; Thomas 2015; Topa 2010). Nonetheless, the factors targeted by interventions to modify adolescent behaviour will depend on whether such interventions seek to prevent initiation of e‐cigarettes (primary prevention) or support their cessation (secondary prevention), as the motivators for use differ. For example, the motivations for initial experimentation with e‐cigarettes in adolescents are likely to differ from those who are seeking to quit (Amato 2021; Kong 2015; Smith 2020). Similarly, behaviours related to the cessation of e‐cigarettes may be more challenging amongst regular users of ENDS experiencing nicotine addiction, compared to regular users of ENNDS, where this may not be the case (Berg 2022). Whilst we anticipate that the majority of interventions aiming to prevent or cease child and adolescent e‐cigarette use will be multicomponent and universal, effective interventions will need to target the specific antecedents of these behaviours.

Why it is important to do this review

Despite the rapidly increasing prevalence in youth, the strength of evidence supporting programmes to prevent or cease (or both) e‐cigarette use in children and adolescents is unknown (Liu 2020). Whilst new programmes and evaluations appear in the literature regularly (Liu 2020), the collective long‐term benefit of these will remain unclear unless synthesised utilising a rigorous systematic review and meta‐analysis framework, including a risk of bias assessment. Given that this is a public health priority and that current evidence on the effectiveness of interventions to prevent adolescent e‐cigarette use is uncertain but rapidly emerging, a living systematic review would be of substantial benefit to the evidence base and help to inform ongoing decision‐making. Living systematic reviews are underpinned by continual, active monitoring of the evidence and immediately incorporate any new relevant evidence that is identified (Living Evidence Network 2019). Findings from a living systematic review could provide policymakers, practitioners, and researchers with timely guidance on the types of programmes that should be funded and implemented in order to address this increasingly important public health issue. As such, a living systematic review employing rigorous methodology is required to provide insight into the effectiveness of current published interventions aiming to prevent or cease child and adolescent e‐cigarette use.

Objectives

The co‐primary objectives of the review were to:

• evaluate the effectiveness of interventions to prevent e‐cigarette use in children and adolescents (aged 19 years and younger) with no prior use, relative to no intervention, waitlist control, usual practice, or an alternative intervention;

• evaluate the effectiveness of interventions to cease e‐cigarette use in children and adolescents (aged 19 years and younger) reporting current use, relative to no intervention, waitlist control, usual practice, or an alternative intervention.

Secondary objectives were to:

• examine the effect of such interventions on child and adolescent use of other tobacco products (e.g. cigarettes, cigars types, and chewing tobacco);

• describe the unintended adverse effects of the intervention on individuals (e.g. physical or mental health of individuals), or on organisations (e.g. intervention displacement of key curricula or learning opportunities for school students) where such interventions are being implemented.

Methods

Criteria for considering studies for this review

Types of studies

We included randomised controlled trials (RCTs), including cluster‐RCTs, factorial RCTs, and stepped‐wedge RCTs, as these are considered to be the highest‐quality study designs to establish intervention effectiveness (McKenzie 2022). Cluster‐RCTs were only eligible for inclusion if the trial consisted of a minimum of two intervention sites and two control sites, as per Cochrane Effective Practice of Organisation of Care (EPOC) recommendations (Cochrane EPOC 2021).

Types of participants

The primary targets of the interventions were children and adolescents aged 19 years or younger. Participants may have included:

• children and adolescents aged 19 years or younger. Studies including participants older than 19 years were only included if the mean age of the study sample at baseline was 19 years or less; or data for children and adolescents aged 19 years or younger could be extracted separately;

• children and adolescents who were current‐users (defined as those that had used e‐cigarettes in the past 30 days), ever‐users (defined as those that had used e‐cigarettes in their lifetime), or never‐users (defined as those who had never tried an e‐cigarette) of e‐cigarettes;

• parents, guardians, and families responsible for the care of children and adolescents aged 19 years or younger;

• professionals within intervention settings (e.g. schools, community, social and welfare settings), including health professionals and teachers, or those in other agencies who may influence e‐cigarette use.

Types of interventions

Intervention

We anticipate that most e‐cigarette interventions evaluated in this review will align with the non‐price MPOWER measures introduced by WHO to reduce the demand for tobacco and recently applied to e‐cigarettes (WHO 2022). MPOWER is an abbreviation used to describe the following tobacco and e‐cigarette control measures: (M) monitor tobacco use and prevention policies; (P) protect people from tobacco smoke; (O) offer help to quit smoking; (W) warn about the dangers of tobacco; (E) enforce bans on tobacco advertising, promotion, and sponsorship; and (R) raise taxes on tobacco. These non‐price measures include education, communication, training, and public awareness provision (WHO 2003), including public media campaigns, and community‐ and school‐based education interventions. Nonetheless, we will consider any educational, experiential, health promotion, and/or psychological, family, behavioural therapy, counselling, management, structural, policy regulation, or legislative reform interventions amongst current, ever‐users, and never‐users of e‐cigarettes, designed to influence the e‐cigarette use of children and adolescents aged 19 years or younger.

Interventions could be conducted in any setting, including community, school, health services, hospitals, or the home. Included interventions must have sought to influence children and/or adolescent (i.e. individuals aged 19 years or younger) e‐cigarette use directly, but could have also sought to influence other risky behaviours such as tobacco use or alcohol consumption. Interventions that target other risk factors were eligible as long as there was a clear component that targets e‐cigarettes. Included interventions could be single‐component or multicomponent (i.e. interventions that include more than one strategy to influence e‐cigarette use), and there was no restriction on intervention duration, facilitator, or modality (i.e. the intervention could be delivered by teachers, self‐led and delivered face‐to‐face, online, or by another modality). We excluded interventions undertaken in laboratories or other simulated contexts.

Comparator

No intervention (i.e. control), waitlist control, usual practice, or an alternative intervention not targeting e‐cigarette use.

Types of outcome measures

The review question and outcomes were developed in consultation with stakeholders, including consumers, health professionals (e.g. community health service managers), and policymakers (e.g. New South Wales Ministry of Health), to ensure that the findings of the review will be used to guide decision‐making on the types of interventions that should be funded to address e‐cigarette use in children and adolescents. The author team consulted with consumers during the development of the review protocol to ensure the scope, aims, and methods of the review met the needs of end‐users in order to maximise impact.

Primary outcomes

• E‐cigarette (ENDS or ENNDS) use in children and adolescents aged 19 years or younger. To match the duality of the co‐primary review objectives, we included measures to assess the effectiveness of interventions to:

  • prevent child and adolescent e‐cigarette use (including measures of e‐cigarette use amongst those who were never‐users) (i.e. those who had never tried an e‐cigarette at baseline);

  • cease e‐cigarette use (including measures of e‐cigarette use amongst children and adolescents who were e‐cigarette  current‐users at baseline).

Measures of e‐cigarette use included:

• current‐use (most frequently defined as use in the past 30 days);

• ever‐use (most frequently defined as any lifetime use).

We only included studies with a follow‐up assessment of at least three months to account for the potential latency of the behaviour change (i.e. e‐cigarette use). E‐cigarette use is mostly evaluated using subjective methods (e.g. parent or child/adolescent report), including surveys and questionnaires. To date, there are no biomarkers specific to e‐cigarette use given that nicotine may or may not be present or may occur in varying concentrations (Benowitz 2020). If multiple measures of the same outcome (i.e. e‐cigarette use) were used, we would utilise the measure with the greatest evidence of reliability and validity; for example, we would include validated measures over those that have not been validated. If a study reported e‐cigarette use at multiple time points, we would select the longest follow‐up period.

Secondary outcomes

• Child and adolescent use of tobacco: we planned to extract data on the impact of the intervention on child and adolescent current‐ or ever‐use of tobacco. Tobacco use can be biochemically validated using carbon monoxide or cotinine, which we planned to use where available over self‐reported tobacco measures. However, since biochemical verification is often considered unnecessary or unfeasible for prevention trials, and as youth tobacco use is often intermittent and concordance has been demonstrated between verified and self‐reported measures, we would also include outcomes assessed using self‐report questionnaires or surveys (Dolcini 2003), if biochemically validated measures were not available. If multiple validated self‐reported measures of the same tobacco use outcome were available, we would utilise the longest measure (e.g. 30‐day point prevalence abstinence over 7‐day point prevalence abstinence). 

• Unintended adverse consequences of the intervention: we planned to extract data on any adverse outcomes where these were specified as such by the included studies. These could have been adverse physical or mental health effects of individuals (e.g. nicotine withdrawal symptoms such as nausea; social connectedness), or the organisations where such interventions are being implemented (e.g. intervention displacement of key curricula or learning opportunities for school students). Such outcomes could be assessed using questionnaires, surveys, or direct observations.

Search methods for identification of studies

We used a comprehensive search developed in consultation with an Information Specialist conducted for peer‐reviewed articles in electronic databases. Our search terms for each electronic database, trial register, and Google Scholar are reported in Appendix 1. 

Electronic searches

We searched the following electronic databases from inception to 1 May 2023: Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (from inception), Ovid MEDLINE (from 1946), Ovid Embase (from 1947), Ovid PsycINFO (from 1806), EBSCO Cumulative Index to Nursing and Allied Health Literature (CINAHL) (from 1947), and Clarivate Web of Science Core Collection (Science Citation Index Expanded and Social Sciences Citation Index) (from 1947). We adapted elements of the search strategy from a previous review (Yoong 2018), in combination with the sensitivity‐ and precision‐maximising version of the Cochrane RCT filter (Lefebvre 2022). This filter was applied to MEDLINE, with the other databases (apart from CENTRAL) using an adapted version. Our search terms included published search filters for "electronic nicotine delivery systems (ENDS) or electronic non‐nicotine delivery systems (ENNDS)" AND "study design" AND "children OR adolescents". 

We did not impose any restrictions on language of publication. Following the initial search of the electronic databases and other sources, an evaluation of the search strategy will be undertaken using a summary table as recommended by Bethel 2021. This will be used to refine the search strategy and sources included in subsequent updates.

Living systematic review considerations

The last major search was in May 2023. We have been running monthly searches since then. We will incorporate new evidence rapidly after it is identified. This review is based on the findings of a search conducted on 1 May 2023.

Searching other resources

In addition to the electronic database searches, we searched for relevant unpublished or grey literature publications in the WHO International Clinical Trials Registry Platform (apps.who.int/trialsearch); US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (www.clinicaltrials.gov); and Google Scholar (first 100 results) (scholar.google.com). In addition, we handsearched the reference lists of relevant systematic reviews, and contacted authors of relevant protocol papers identified by the electronic database searches.

Living systematic review considerations

We are conducting monthly searches of trial registries (WHO International Clinical Trials Registry Platform; US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov) and searches of other resources (Google Scholar; and reference lists of included studies and relevant systematic reviews) every six months. As additional steps to inform the living systematic review, we are contacting the corresponding authors of ongoing studies as they are identified and asking them to advise when results are available, or to share early or unpublished data.

We will review search strategies on a yearly basis to ensure that they address any changes in terminology, searched databases, or the topic area.

Data collection and analysis

Selection of studies

Pairs of review authors (CBa, RH, JM, HT) independently screened the titles and abstracts of all studies using Covidence software (Covidence). Prior to commencing screening, review authors independently piloted the abstract and full‐text review instruments with 100 citations and 20 full‐text articles to ensure consistency between review authors. Any discrepancies between review authors regarding title and abstract screening were resolved via consensus, or by consulting a third review author (CBi) when required. 

We obtained the full‐text articles of studies that could not clearly be excluded on the basis of title and abstract. Pairs of review authors (CBa, HT) independently assessed the full‐text articles in Covidence for inclusion in the review (Covidence). Any discrepancies between review authors regarding full‐text screening were resolved via consensus, or by consulting a third review author when required (CBi). We documented the reasons for excluding any full‐text manuscripts in the 'Characteristics of excluded studies' table. 

Living systematic review considerations

We will immediately screen any new citations retrieved by the monthly searches.

Data extraction and management

For included studies, we planned that two review authors (CBa, SMc) would independently extract information using a pre‐piloted data extraction form developed by the review team. Any discrepancies regarding data extraction between review authors would be resolved via consensus, or by consulting a third review author (HT) when required. We planned to extract the following data from each included study in sufficient detail to complete a 'Characteristics of included studies' table.

• General information: author name, title, publication date, country, funding source and potential conflicts of interest.

• Study methods: study design, setting, duration, sample size, number of experimental conditions, and number of participants.

• Participant and PROGRESS‐Plus characteristics: age, gender, religion, education, race and ethnicity, place of residence, social capital, socioeconomic status, baseline smoking and e‐cigarette status (e.g. current, ever).

• Intervention characteristics: intervention description, intensity and length of the intervention, theoretical underpinning, intervention components, and modality (e.g. online, face‐to‐face).

• Comparator characteristics: comparator description, intensity and length of the comparator, theoretical underpinning, comparator components, and modality (e.g. online, face‐to‐face).

• Study primary and secondary outcomes (aligned to the review outcomes): outcome definition, data collection method, validity of measures used, effect size and measures of outcome variability.

• Information regarding frequency of e‐cigarette use, device type, primary flavour preference, and presence of nicotine within the e‐cigarettes.

• Information to enable risk of bias assessment.

To ensure that specific information on health equity is provided, we planned to extract data on place of residence, race, occupation, gender, religion, education, socioeconomic status, and social capital (e.g. neighbourhood, community, or family support), which are known as the PROGRESS‐Plus characteristics (O'Neill 2014). We planned to list all treatment arms in the 'Characteristics of included studies' table, even if they are not used in the review.

For ongoing studies, two review authors (CBa, JM) independently extracted information using a pre‐piloted data extraction form developed by the review team. Any discrepancies regarding data extraction between the review authors were resolved via consensus, or by consulting a third review author (HT) when required. We extracted the following data from the ongoing studies which we detailed in the ‘Characteristics of ongoing studies’ tables.

• General information: author name, title, publication date, country.

• Study methods: study design, setting, duration, sample size, number of experimental conditions, and number of participants.

• Participant: age and place of residence.

• Intervention and comparator characteristics: intervention description, components, and modality.

• Study primary and secondary outcomes (aligned to the review outcomes): outcome definition and data collection method.

Assessment of risk of bias in included studies

For all included study designs, we planned to assess the risk of bias using the Cochrane RoB 2 tool (Higgins 2022a). We planned to apply the RoB 2 tool to both primary and secondary review outcomes from each included study to assess and rate each outcome as low, high, or some concerns for the following risk of bias domains: randomisation process, deviations from the intended intervention, missing outcome data, measurement of the outcome, and selection of the reported result. We planned to assess cluster‐RCTs for an additional risk of bias domain: timing of identification and recruitment of participants. We planned to assess stepped‐wedge trials using the RoB 2 tool for cluster‐randomised trials as suggested in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2022b). The effect of interest would be effect of assignment to the intervention at baseline (i.e. intention to treat). If included studies report results for multiple follow‐up periods, we would assess risk of bias on the most recent (i.e. longest) study follow‐up. 

We planned to use the Cochrane RoB 2 guidance document and Excel spreadsheet to implement the tool, in addition to the supporting materials available on the risk of bias website (Risk of bias tools 2019). We would determine risk of bias assessments using algorithms in the RoB 2 tool, based on the answers to the signalling questions. When deciding the overall risk of bias for a study, we planned to use the recommended criteria below. However, if we considered there was sufficient reason to override the algorithm, we would do so and provide a justification.

• Low risk of bias: study is judged at low risk of bias if all domains are low risk of bias for a given result.

• Some concerns: study is judged as some concerns if at least one domain for that result is judged as some concerns, but no domains are classified as high risk of bias for that result.

• High risk of bias: study is judged at high risk of bias for a given result if at least one domain is judged at high risk of bias for that result, or the study is judged as having some concerns for multiple domains for that result.

We planned for two review authors (SLY, ES) to independently assess risk of bias on all studies. Any discrepancies between review authors regarding risk of bias assessments would be resolved via consensus, or by consulting a third review author when required (CBa). We planned to present risk of bias tables for the co‐primary outcomes from individual studies and list the risk of bias for the secondary outcomes in the 'Characteristics of included studies' tables.

Assessment of bias in conducting the systematic review

We planned to conduct the review according to the published protocol (Barnes 2022), and report any deviations from it in the 'Differences between protocol and review' section of the systematic review.

Measures of treatment effect

For the co‐primary outcomes, we planned to undertake multiple meta‐analyses using a random‐effects model. For prevention interventions, we planned to pool these interventions and conduct two analyses using the outcome measures of ‘ever‐use’ and ‘current‐use’. For cessation interventions, we planned to pool these interventions and conduct one analysis using the outcome measure of ‘current‐use’. We expected that measures of the primary outcomes would be reported as dichotomous variables. For dichotomous outcomes, we planned to calculate the odds ratio. For continuous outcomes (e.g. measures of the frequency of adverse effects), we planned to calculate a mean difference (MD) if the same measures were used across studies to assess the same outcome. If studies used different measures for the same outcome, we would report a standardised mean difference (SMD). To facilitate interpretation of SMD, in the summary of findings table, we planned to re‐express standardised effects as absolute MDs consistent with recommendations in Chapter 15 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2022a). Alternatively, we planned to calculate an SMD if different measures were used across studies to assess the same outcome. We planned to calculate 95% confidence intervals (CIs) for all estimated intervention effects. 

We planned to use other measures of variance (i.e. standard errors, CIs and P values) to calculate standard deviations if they were not provided by studies, applying the formulas outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2022). If adjusted and unadjusted estimates were reported within studies, we would use the unadjusted estimates due to only RCTs being included and to reduce potential heterogeneity from different adjustments. For cluster‐RCTs, if clustering has been appropriately accounted for, we would combine these trials with individual RCTs (Higgins 2022a).

Unit of analysis issues

We planned to examine cluster‐RCTs for unit of analysis errors and record these if they occurred in the risk of bias tables. We planned to combine data from cluster‐RCTs with other outcome data if clustering had been appropriately accounted for. If clustering was not accounted for, we would obtain the intraclass correlation coefficient (ICC) and mean cluster size and use this information to calculate the design effect and effective sample size to allow these cluster‐RCTs to be included in the meta‐analyses (Higgins 2022a). Where the ICC was not reported, we would use median ICC value from similar studies if available, or use and report an ICC from a well‐conducted cluster‐RCT if a median ICC from a similar study was not available. 

For studies with more than two experimental groups, we planned to address these in accordance with the guidance in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2022a). For multi‐arm trials where multiple interventions were relevant to the aims of the review, we planned to split the control group into two or more groups with a smaller sample to form independent comparisons. For stepped‐wedge RCTs, we planned to assess whether time trends had been accounted for in the analysis of the original trial.

Dealing with missing data

We planned to assess and report missing data and dropouts in the included studies within the review. We planned to contact the authors of the included studies to obtain missing data if required. If possible, we would calculate missing variance estimates using other available data following the formula recommended in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2022a). If missing data could not be calculated from other available data or obtained from study authors, values would have been left as missing and would not be imputed. We planned to document the evidence of potential reporting bias in the risk of bias tables.

Assessment of heterogeneity

If appropriate, we planned to conduct a meta‐analysis to quantify the overall effectiveness of the interventions for the primary review outcome. We planned to assess heterogeneity by examining forest plots for asymmetry, conducting Chi² tests, and quantifying statistical heterogeneity by calculating the I² statistic as well as reporting and considering study characteristics, including study participants, intervention, outcomes, and comparators (Higgins 2022a).

Assessment of reporting biases

We planned to assess reporting bias by comparing published reports with information provided in study protocols and registers. We also planned to explore reporting bias in any meta‐analyses conducted by plotting contour‐enhanced funnel plots and visually assessing them for asymmetry and outliers. 

Data synthesis

We planned that one review author (CBa) would enter data into Review Manager Web for analysis (RevMan Web 2022), and a second review author (HT) would check the data entry. For each primary and secondary outcome separately, we planned to pool measures of outcomes within a meta‐analysis using a random‐effects model. We planned to conduct multiple primary analyses to align with the co‐primary objectives of the review. First, we planned to pool interventions to prevent child and adolescent e‐cigarette use and conduct two analyses using the outcome measures of 'ever‐use' and 'current‐use'. Second, we planned to pool interventions to cease child and adolescent e‐cigarette use and conduct one analysis using the outcome measure of 'current‐use'.

As many recommended interventions to prevent e‐cigarette use are population based, we anticipated that there would be studies where measures of e‐cigarette use included mixed samples comprised of current‐, ever‐, and never‐users of e‐cigarettes at baseline. For example, studies may have expressed the effects of the intervention on changes in population prevalence of e‐cigarette use. Such outcomes are common in prevention trials of adolescent substance use. Where data regarding the effects of the intervention on those who were never‐users at baseline are not otherwise reported, we would seek this information from the study authors. Where this information is not forthcoming, we would include measures of this outcome that used a mixed sample (i.e. e‐cigarette current‐, ever‐, and never‐users) at baseline where most (i.e. ≥ 50%) of the baseline sample were never‐users. Where this occurred, we would note this in the text and 'Characteristics of included studies' tables, and explore in sensitivity analyses as described below.

For cessation studies that include a mixed group of e‐cigarette users (e.g. current‐ or ever‐users) in their baseline sample, we planned to utilise effect estimates reported for current‐users at baseline. Where this information is not available, we planned to seek data from study authors to enable assessment. Where these data are not forthcoming, we would use effect estimates calculated from a mixed baseline sample (e.g. current‐, ever‐, or never‐users), only if the majority (≥ 50%) of the baseline sample were current‐users. Where this occurs, we would note this in the text and 'Characteristics of included studies tables' and explore in sensitivity analyses.

Where the data are unsuitable for pooling in meta‐analyses due to missing or incomplete data, we planned to conduct synthesis using vote‐counting approaches based on direction of effect following the procedures outlined in the Cochrane Handbook for Systematic Reviews of Interventions and the Synthesis Without Meta‐analysis (SWiM) guidelines (Higgins 2022a; Thomson 2020). This would have included vote‐counting based on the direction of intervention effect. We would present an overview of these findings and summary of intervention effects in a table.

Living systematic review considerations

Whenever we find new evidence (i.e. studies, data or information) meeting the review inclusion criteria, we will immediately extract the data, assess risk of bias, and incorporate the evidence in the synthesis. We will incorporate any new study data into existing meta‐analyses using the standard approaches outlined in the Data synthesis section. We will not use formal sequential meta‐analysis approaches for updated meta‐analyses. We will wait until the accumulating evidence changes one or more of the following components of the review before republishing the review:

• primary outcome findings;

• credibility (e.g. GRADE rating) of the primary outcomes;

• new settings, populations, interventions, or comparisons studied.

Subgroup analysis and investigation of heterogeneity

We planned to undertake a subgroup analysis for each primary and secondary outcome based on the tobacco smoking status (current smoker versus past/never‐smoker) of participants at baseline. The interpretation of e‐cigarette prevention and cessation interventions effects will differ based on baseline smoking status. Initially, we were not intending to investigate any other subgroup analyses as we anticipate that the number of included studies will be small. However, as the evidence base grows and the number of included studies increases, we will conduct subgroup analyses on the primary outcomes to explore the potential causes of heterogeneity (where the I² statistic is more than 75%). We will conduct subgroup analyses by statistically comparing the between‐subgroup treatment effects, following the procedures recommended in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2022a). We will only conduct subgroup analyses if a minimum of two studies per subgroup are available. We will seek data from study authors to undertake subgroup analyses where this information is not reported. Where data were available, we planned to undertake the following subgroup analyses.

• Setting: interventions delivered in different settings, including schools, community, social and welfare settings.

• Population: interventions targeting vulnerable population groups (e.g. low socioeconomic status), age, users of ENDS or ENNDS, and device type.

• Intervention: delivery modes (e.g. telephone, the internet, or face‐to‐face), intervention dosage (e.g. number and duration of contacts or components), and intervention type (e.g. multi‐risk interventions targeting other risk factors, but still include an e‐cigarette component and outcome measures; and interventions solely targeting e‐cigarettes).

Sensitivity analysis

We planned to conduct a sensitivity analysis by removing studies classified at high risk of bias (defined above) and repeating the meta‐analysis for the primary outcomes to examine the impact of the study methodological risk of bias. We also planned to conduct sensitivity analyses for studies with mixed samples (e.g. current‐, ever‐, and never‐users of e‐cigarettes) at baseline, whereby we would remove studies with mixed samples at baseline from the analysis. 

Summary of findings and assessment of the certainty of the evidence

We planned to use GRADE to assess the overall certainty of the evidence for the primary and secondary review outcomes (Higgins 2022a; Schünemann 2022).

• E‐cigarette use (ENDS or ENNDS)

• Child and adolescent use of tobacco

• Unintended adverse consequences of the intervention

We planned to prioritise ever‐use and current‐use outcome measures as per our meta‐analysis. We also planned to summarise assessments related to child and adolescent use of tobacco, and unintended adverse effects of the intervention. The most recent (i.e. longest) follow‐up time point will be the time point of interest. We planned to present the GRADE findings within summary of findings tables developed using GRADEpro GDT software. These tables would also report for each outcome the treatment effect estimate, number of included studies and participants, and the assessment of the overall certainty of the evidence. Two review authors would independently assess the certainty of the evidence, with any disagreements resolved by consensus, or by consulting a third review author if required.

As per GRADE recommendations, we planned to assess the primary and secondary outcome measures against the relevant GRADE criteria to obtain an overall rating and overall level of certainty of the evidence. We would consider the following GRADE criteria for lowering the certainty of the evidence.

• Risk of bias (i.e. an outcome assessed as some concerns or high risk of bias)

• Inconsistency (i.e. wide variance of point estimates across studies, minimal overlap of CIs, or a combination)

• Indirectness 

• Imprecision (i.e. small study, defined as fewer than 400 participants)

• Publication bias

Based on the GRADE assessment, we would determine the level of certainty (high, moderate, low, or very low) that the estimates of the effect are correct. 

We planned to use the guidance outlined by Murad 2017 for outcomes that are synthesised by vote‐counting. If synthesis was not appropriate, we would apply GRADE to individual studies. For all outcomes, we planned to document our decisions to downgrade the certainty of the evidence for the above criteria using footnotes.

Methods for future updates

Living systematic review considerations

We will review the review scope and methods approximately yearly, or more frequently if appropriate, in light of potential changes in the topic area or the evidence being included in the review (e.g. new review methods available, or additional comparisons, interventions, subgroups, or outcomes). 

We will consider the necessity for the review to be living each year against the required criteria for living systematic reviews, including whether the uncertainty in the evidence is ongoing; whether further relevant research is likely; and by assessing the ongoing relevance of the question to decision‐makers.

Results

Description of studies

Results of the search

The search of electronic databases, conducted on 1 May 2023, yielded 7141 citations (Figure 1). We identified an additional 287 records from our search of trial registries and Google Scholar. We identified no additional records from our contact with the authors of ongoing studies, including those with published protocols, or from handsearching the reference lists of ongoing studies. Following screening of titles and abstracts, we obtained the full texts of 115 studies (121 records) for further review. None of these studies met the inclusion criteria for the review. We identified 22 studies (28 records) as ongoing studies that may be eligible for inclusion in a future review update.

1.

Study flow diagram.

Of the 22 ongoing studies, 11 studies are examining the effectiveness of interventions to prevent e‐cigarette use; seven studies are examining the effectiveness of cessation interventions; and four studies are examining interventions to both prevent and cease e‐cigarette use. Half of the studies are being conducted in the USA (n = 11), followed by Australia (n = 2), Canada (n = 2), Germany (n = 1), and Switzerland (n = 1) (country not reported in the remaining studies).

The ongoing studies are being conducted in a variety of settings. For example, 12 studies are examining interventions to prevent e‐cigarette use in schools; seven studies are examining the effect of text‐message or social media type interventions; and four studies are examining interventions conducted in health services to cease adolescent e‐cigarette use. These studies are summarised in the Characteristics of ongoing studies tables.

Included studies

No study met the inclusion criteria.

Excluded studies

Of the 110 studies (116 records) evaluated at the full‐text review stage, we considered 88 studies to be ineligible. The primary reasons for exclusion included: inappropriate outcome (27 studies: 18 studies did not include a measure of e‐cigarette use; 7 studies had a follow‐up of less than 3 months; and 2 studies included a combined measure of tobacco and e‐cigarette use); intervention (12 studies: all 12 studies did not include a specific intervention component targeting e‐cigarettes); study design (31 studies: 15 studies were observational; 8 studies were pre‐post; 2 studies were non‐RCTs; 1 study was a cluster‐RCT with only 1 control and intervention site; and 5 studies were other types of design); and participants (18 studies: all 18 studies included participants with a mean age of over 19 years at baseline). The reasons for exclusion of the excluded studies are reported in the Characteristics of excluded studies tables.

Risk of bias in included studies

Allocation

We identified no studies that met the inclusion criteria and therefore assessed no studies for methodological quality.

Blinding

We identified no studies that met the inclusion criteria and therefore assessed no studies for methodological quality.

Incomplete outcome data

We identified no studies that met the inclusion criteria and therefore assessed no studies for methodological quality.

Selective reporting

We identified no studies that met the inclusion criteria and therefore assessed no studies for methodological quality.

Other potential sources of bias

We identified no studies that met the inclusion criteria and therefore assessed no studies for methodological quality.

Effects of interventions

We identified no studies that met the inclusion criteria and therefore carried out no analysis.

Discussion

Summary of main results

This review sought to assess the effectiveness of interventions to prevent or cease e‐cigarette use in children and adolescents (aged 19 years and younger). Despite employing a comprehensive search strategy, no studies were deemed eligible for inclusion in the review. However, we identified 22 ongoing studies. The findings suggest the conduct and publication of research trials testing prevention and cessation interventions should be a priority for the field to guide investments in effective e‐cigarette prevention initiatives for youth internationally.

A number of factors may have contributed to the absence of published trials meeting the review eligibility criteria. First, e‐cigarettes are considered an emerging health issue in youth, only entering the market since early 2004. As such, e‐cigarette research with this population is likely still in its infancy. For example, our search strategy found that more than 75% of citations included in title and abstract screening were published in the past five years.

Second, many of the initiatives to date have focused on policy and regulatory changes as a precautionary approach that may not be amenable to assessment using a randomised controlled trial design. For example, studies examining the potential impact of e‐cigarette policies, including restrictions on e‐cigarette sales and marketing, on adolescent e‐cigarette use are often evaluated as part of natural experiments. Further, several studies have used observational data from national youth surveys to examine the impact of the Tobacco 21 laws, which increased the minimal legal sales for tobacco products to 21 years of age, on daily smoking and e‐cigarette use amongst US adolescents (Dai 2021; Kessel Schneider 2016; Kim 2021). Whilst findings suggest that the laws have had a positive impact on reducing youth tobacco use, e‐cigarette usage continues to increase (Kim 2021). Additionally, non‐randomised trial designs are frequently employed to assess the potential impact of initiatives where random assignment may be impractical, such as mass media or digital campaigns on adolescent e‐cigarette behaviours. For example, Graham and colleagues employed a non‐RCT design to evaluate the effect of a digital e‐cigarette cessation programme on abstinence rates in youth, concluding that the programme showed promise in reducing or stopping youth e‐cigarette use (Graham 2020). It is likely that research employing other non‐randomised research designs or natural experiments have been undertaken but excluded from this review.

Third, staged approaches to the development of health innovations recommend formative research and piloting prior to investments in large‐scale randomised trials. Characteristics of excluded studies suggest that the evidence base is in this formative stage, employing formative designs, such as pre‐post or non‐randomised study designs, to assess the potential effect, acceptability, and feasibility of new interventions. For example, the CATCH My Breath study by Helder and colleagues conducted a pilot study employing a non‐randomised design to determine the feasibility and initial effectiveness of an e‐cigarette prevention programme in Texas middle schools (Kelder 2021). The pilot evaluation found the programme to be effective in reducing adolescent e‐cigarette initiation by 46%, as well as improving adolescent knowledge and outcome expectations related to e‐cigarettes (Kelder 2021) Additionally, Gaiha and colleagues conducted a pre‐test – post‐test study with Alabama middle and high school students to assess adolescent knowledge about e‐cigarettes and intentions to try before and after implementing the Stanford Tobacco Prevention Toolkit (Gaiha 2021). The findings indicated that the intervention was associated with significantly increased adolescent knowledge about e‐cigarettes and significantly lower intentions to try e‐cigarettes (Gaiha 2021). Whilst neither pilot was eligible for inclusion in the review, both interventions are currently being tested via RCTs and have been identified as ongoing studies that are likely to be included in future updates.

Finally, we excluded a number of studies because they did not examine the effects of intervention on child or adolescent ever or current e‐cigarette use (i.e. the review primary outcome). Instead, many studies measured child or adolescent susceptibility or intentions to use e‐cigarettes (Cartujano‐Barrera 2022; England 2021; Kowitt 2022). Other studies did include measures of child and adolescent ever or current use, but used a follow‐up period of less than three months. Such studies may reflect the challenges of undertaking trials of prevention interventions, which need to accommodate long follow‐up periods given the latency of the targeted behaviour change.

Overall completeness and applicability of evidence

We did not identify any randomised trials of e‐cigarette prevention or cessation interventions eligible for inclusion in the review. Nonetheless, we did identify 22 ongoing studies that are likely to be included in subsequent updates of this review. The number of ongoing studies suggest that trial evidence will soon rapidly emerge. Ongoing surveillance of this evidence has been recommended (Barnes 2023). Specifically, living systematic reviews are recommended in these instances where there is a high level of uncertainty in the existing evidence that will impact on the conclusions of the review (Cochrane 2019). The review will be undertaken as a living systematic review from publication of this first review given its strong alignment to required criteria for living systematic reviews.

Quality of the evidence

We did not identify any studies that met the inclusion criteria and thus were unable to assess the quality of the evidence.

Potential biases in the review process

We undertook a comprehensive search for studies, including searching electronic databases in addition to trial registries and Google Scholar, with no restrictions on publication date or language of publication. It is possible that the search strategy did not capture unregistered and/or unpublished trials in the grey literature.

Agreements and disagreements with other studies or reviews

The absence of evidence on the effect of interventions to prevent or cease adolescent e‐cigarette use is consistent with the findings of previous reviews. For example, Liu and colleagues conducted an overview of adolescent e‐cigarette prevention and cessation programmes and identified seven prevention or cessation programmes that had been empirically evaluated. Whilst these programmes were also identified in the search strategy for our review, they did not meet our inclusion criteria, mainly due to studies predominately examining the impact of the programmes on intentions and attitudes towards e‐cigarettes instead of ever‐ or current‐use (Liu 2020).

Authors' conclusions

Implications for practice.

Due to the paucity of empirical data on intervention effectiveness available in this review, evidence to support decisions of policymakers, practitioners, and researchers on the types of health promotion programmes or other activities that should be implemented to support the prevention or cessation of e‐cigarette use amongst adolescents is lacking. In the absence of such evidence, policymakers and practitioners are instead reliant on existing guidance frameworks and consensus statements, such as the WHO Framework Convention on Tobacco Control, to inform decision‐making and practice (WHO 2003). The framework, which has recently been applied to e‐cigarettes, provides guidance to assist with country‐level implementation of interventions to reduce the demand for tobacco and e‐cigarettes (WHO 2021).

Implications for research.

Given the lack of evidence of the effectiveness of interventions to prevent or cease child and adolescent e‐cigarette use, any research in this space would be of considerable value. Once published, the ongoing studies identified within this review will provide substantial insight into the potential effectiveness of interventions to prevent and/or cease child and adolescent e‐cigarette use within numerous settings across multiple countries. Studies are predominately being conducted in the USA (n = 11), followed by Australia (n = 2), Canada (n = 2), Germany (n = 1), and Switzerland (n = 1) (country not reported in the remaining studies), indicating that there is a need for trials conducted within a more diverse range of countries in order for findings to be generalisable. Additionally, the number of studies examining the effectiveness of prevention studies (n = 11) is higher than the number of cessation studies (n = 7) (the remaining four studies examine both), indicating that more studies are potentially required to identify the types of interventions that may be effective in ceasing child and adolescent e‐cigarette use.

What's new

Date	Event	Description
15 December 2023	Amended	Plain language summary title added

History

Protocol first published: Issue 11, 2022
Review first published: Issue 11, 2023

Appendices

Appendix 1. Search strategy

Database: Ovid MEDLINE(R) and Epub Ahead of Print, In‐Process & Other Non‐Indexed Citations and Daily

Date range: from inception ‐ 1^st May 2023

#	Searches
1	Electronic Nicotine Delivery Systems/
2	Vaping/
3	e‐cig*.mp.
4	(electr* adj2 cig*).mp.
5	(electr* adj2 nicotine).mp.
6	(nicotine adj2 delivery).mp.
7	((ENND* or END*) adj3 nicotine).mp.
8	(vape or vaping).tw,kw.
9	e‐liquid.mp.
10	e‐nicotine.mp.
11	electronic hookah*.mp.
12	e‐hookah*.mp.
13	e‐shisha*.mp.
14	e‐waterpipe*.mp.
15	e‐pipe*.mp.
16	or/1‐15
17	child/
18	adolescent/
19	adolescen*.mp.
20	child*.mp.
21	teen*.mp.
22	youth*.mp.
23	student/
24	high school*.mp.
25	middle school*.mp.
26	primary school*.mp
27	elementary school*.mp.
28	or/17‐27
29	exp Health Education/
30	exp Health Promotion/
31	exp Behavior Therapy/
32	exp Counseling/
33	organizational policy/
34	Public Policy/
35	exp Health Policy/
36	exp Inservice Training/
37	promot*.tw,kw.
38	educat*.tw,kw.
39	program*.tw,kw.
40	(policy or policies).tw,kw.
41	train*.tw,kw.
42	intervention*.tw,kw.
43	prevention.mp
44	cessation.mp
45	cease.mp
46	reduc*.mp.
47	Or/29‐46
48	16 and 28 and 47
49	randomized controlled trial.pt.
50	controlled clinical trial.pt.
51	randomized.ab.
52	placebo.ab.
53	drug therapy.fs.
54	randomly.ab.
55	trial.ab.
56	groups.ab.
57	or/49‐56
58	exp animals/ not humans.sh.
59	57 not 58
60	48 and 59

Database: Ovid APA PsycINFO 

Date range: from inception ‐ 1^st May 2023

#	Searches
1	Electronic Cigarettes/
2	e‐cig*.mp.
3	(electr* adj2 cig*).mp
4	(electr* adj2 nicotine).mp.
5	(nicotine adj2 delivery).mp.
6	((ENND* or END*) adj3 nicotine).mp.
7	(vape or vaping).mp.
8	e‐liquid.mp.
9	e‐nicotine.mp.
10	electronic hookah*.mp.
11	e‐hookah*.mp.
12	e‐shisha*.mp.
13	e‐waterpipe*.mp.
14	e‐pipe*.mp.
15	or/1‐14
16	child*.mp.
17	adolescen*.mp.
18	Teen*.mp.
19	youth.mp.
20	High school students/
21	Middle School Students/
22	Primary School Students/
23	Elementary School Students/
24	high school*.mp.
25	middle school*.mp.
26	primary school*.mp
27	elementary school*.mp.
28	or/16‐27
29	health education/
30	health promotion/
31	health literacy/
32	lifestyle changes/
33	exp behavior therapy
34	exp counseling/
35	organizational policy/
36	exp policy making/
37	exp inservice training/
38	promot*.tw.
39	educat*.tw.
40	program*.tw.
41	(policy or policies).tw.
42	train*.tw.
43	Intervention*.tw.
44	Prevention/
45	cessation.mp.
46	cease.mp.
47	reduc*.mp.
48	or/29‐47
49	15 and 28 and 48
50	Randomized Controlled Trials/
51	Clinical Trials/
52	randomized controlled trial.pt.
53	controlled clinical trial.pt.
54	randomized.ab.
55	placebo.ab.
56	randomly.ab.
57	Trial.ab.
58	groups.ab.
59	or/50‐58
60	exp animals/ not humans.sh.
61	59 not 60
62	49 and 61

Database: Ovid Embase

Date range: from inception ‐ 1^st May 2023

#	Searches
1	electronic cigarette/
2	Vaping/
3	e‐cig*.mp.
4	(electr* adj2 cig*).mp
5	(electr* adj2 nicotine).mp.
6	(nicotine adj2 delivery).mp.
7	((ENND* or END*) adj3 nicotine).mp.
8	(vape or vaping).mp.
9	e‐liquid.mp.
10	e‐nicotine.mp.
11	electronic hookah*.mp.
12	e‐hookah*.mp.
13	e‐shisha*.mp.
14	e‐waterpipe*.mp.
15	e‐pipe*.mp.
16	or/1‐15
17	child/
18	child*.mp.
19	adolescent/
20	adolescen*.mp.
21	juvenile/
22	teen*.mp.
23	exp middle school student/ or exp high school student/
24	exp primary school/
25	high school*.mp.
26	middle school*.mp.
27	primary school*.mp
28	elementary school*.mp.
29	or/17‐28
30	exp health education/
31	consumer health information/
32	behavior therapy/
33	exp counseling/
34	policy/
35	health care policy/
36	in service training/
37	promot*.tw
38	educat*.tw.
39	program*.tw.
40	(policy or policies).tw.
41	train*.tw.
42	Intervention*.tw
43	prevention/
44	cessation.mp.
45	cease.mp.
46	reduc*.mp.
47	or/30‐46
48	16 and 29 and 47
49	randomized controlled trial/
50	controlled clinical trial/
51	randomized controlled trial.pt.
52	controlled clinical trial.pt.
53	randomized.ab.
54	placebo.ab.
55	randomly.ab.
56	Trial.ab.
57	groups.ab.
58	or/49‐57
59	(animal/ or nonhuman/) not human/
60	58 not 59
61	48 and 60

Database: Cochrane CENTRAL in the Cochrane Library

Date range: from inception ‐ 1^st May 2023

#	Searches
1	MeSH descriptor: [Electronic Nicotine Delivery Systems] this term only
2	MeSH descriptor: [Vaping] this term only
3	e‐cig*
4	(electr* near/2 cig*)
5	(electr* near/2 nicotine)
6	(nicotine near/2 delivery)
7	((ENND* or END*) near/3 nicotine)
8	(vape or vaping)
9	e‐liquid
10	e‐nicotine
11	electronic hookah*
12	e‐hookah*
13	e‐shisha*
14	e‐waterpipe*
15	e‐pipe*
16	{OR #1‐#15}
17	child* or adolescen*
18	MeSH descriptor: [Schools] this term only
19	"secondary school*" OR "middle school*" OR "high school*"
20	"primary school*" OR "elementary school*"
21	{OR #17‐#20}
22	MeSH descriptor: [Health Education] explode all trees
23	MeSH descriptor: [Health Promotion] explode all trees
24	MeSH descriptor: [Behavior Therapy] explode all trees
25	MeSH descriptor: [Counseling] explode all trees
26	MeSH descriptor: [Organizational Policy] this term only
27	MeSH descriptor: [Public Policy] this term only
28	MeSH descriptor: [Health Policy] explode all trees
29	MeSH descriptor: [Inservice Training] explode all trees
30	promot*
31	educat*
32	program*
33	(policy or policies)
34	train*
35	Intervention*
36	prevent*
37	cessation
38	cease
39	reduc*
40	{OR #22‐#39}
41	{AND #16,#21,#40}

Database: EBSCO CINAHL

Date range: from inception ‐ 1^st May 2023

#	Searches
1	(MH "Electronic Cigarettes")
2	(MH "Vaping")
3	“e‐cig*”
4	(electr* n2 cig*)
5	(electr* n2 nicotine)
6	(nicotine n2 delivery)
7	((ENND* or END*) n3 nicotine)
8	(vape or vaping)
9	“e‐liquid”
10	“e‐nicotine”
11	“electronic hookah*”
12	“e‐hookah*”
13	“e‐shisha*”
14	“e‐waterpipe*”
15	“e‐pipe*”
16	S1 or S2 or S3 or S4 or S5 or S6 or S7 or S8 or S9 or S10 or S11 or S12 or S13 or S14 or S15
17	(MH “Child”)
18	(MH “adolescence”)
19	“adolescen*”
20	“teen*”
21	“youth*”
22	“child*”
23	(MH "Students, High School") OR (MH "Students, Middle School")
24	MH "Students, Elementary"
25	"high school*"
26	"middle school*"
27	"primary school*"
28	"elementary school*"
29	S17 or S18 or S19 or S20 or S21 or S22 or S23 or S24 or S25 or S26 or 27 or 28
30	(MH “Health Education+”)
31	(MH “Health Promotion+”)
32	(MH “Behavior Therapy+”)
33	(MH “Counseling+”)
34	(MH “Organizational Policies+”)
35	(MH “Public Policy+”)
36	TI promot* or AB promot*
37	TI educat* or AB educat*
38	TI program* or AB program*
39	TI (policy or policies) or AB (policy or policies)
40	TI train* or AB train*
41	"prevention"
42	"cessation"
43	cease
44	reduc*
45	S30 or S31 or S32 or S33 or S34 or S35 or S36 or S37 or S38 or S39 or S40 or S41 or S42 or S43 or S44
46	PT randomized controlled trial
47	PT clinical trial
48	AB randomized
49	AB placebo
50	AB randomly
51	AB Trial
52	AB groups
53	S46 or S47 or S48 or S49 or S50 or S51 or S52
54	S16 and S29 and S45 and S53
55	Limit 54 to (human)

Database: Clarivate Web of Science Core Collection (Science Citation Index Expanded and Social Sciences Citation Index)

Date range: from inception ‐ 1^st May 2023

#	Sets
1	(((((((((((((TS=(Electronic Nicotine Delivery Systems*)) OR TS=(Vaping )) OR TS=(e‐cig* )) OR TS=((electr* near/2 cig*) )) OR TS=((electr* near/2 nicotine) )) OR TS=((nicotine near/2 delivery) )) OR TS=(((ENND* or END*) near/3 nicotine) )) OR TS=((vape or vaping) )) OR TS=(e‐nicotine )) OR TS=(electronic hookah* )) OR TS=(e‐hookah* )) OR TS=(e‐shisha* )) OR TS=(e‐waterpipe* )) OR TS=(e‐pipe*)
2	(((((((TS=(child* )) OR TS=(adolescen* )) OR TS=(juvenile)) OR TS=(teen*)) OR TS=(high school*)) OR TS=(middle school*)) OR TS=(primary school*)) OR TS=(elementary school*)
3	((((((((((((((((((TS=(health educat*)) OR TS=(health promot*)) OR TS=( health literac* )) OR TS=(lifestyle change*)) OR TS=(behavior therapy* )) OR TS=(counsel*)) OR TS=( organizational polic*)) OR TS=(policy making*)) OR TS=(inservice training*)) OR TS=( promot* )) OR TS=(educat*)) OR TS=( program*)) OR TS=( (policy or policies))) OR TS=( train) OR TS=(prevention)) OR TS=(cessation)) OR TS=(cease)) OR TS=(reduc*))
4	((((((TS=(randomized controlled trial)) OR TS=(controlled clinical trial)) OR AB=(randomized)) OR AB=(placebo)) OR AB=(randomly)) OR AB=(Trial)) OR AB=(Groups)
5	#1 AND #2 AND #3 AND #4

Trial Register: US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (www.clinicaltrials.gov);

Condition or Disease: Electronic Nicotine Delivery Systems OR Vaping

Other Terms: adolescent OR child OR teen OR youth

Trial Register: WHO International Clinical Trials Registry Platform (apps.who.int/trialsearch);

Combinations of condition and population related terms:

ENDS terms

"electronic nicotine delivery systems"

"E Cig"

"E Cigarette"

"E Cigarettes"

"E Cigs"

"Electronic Cigarette"

"Electronic Cigarettes"

"E Cigarette Use"

"Ecigarette Use"

"E Cigarette Uses"

"Ecigarette Uses"

"E Cig Use"

"ECig Use"

"E Cig Uses"

"ECig Uses"

"Electronic Cigarette Use"

"Electronic Cigarette Uses"

Vape

Vapes

vaping

"e‐cig"

"e‐cigarette"

"e‐cigarettes"

ENDS

ENNDS

Population related terms:

adolescent

Adolescence

adolescents

Teen

Teenager

Teenagers

Teens

Youth

Youths

child

children

Web search: Google Scholar

(adolescent OR child OR teen OR youth) AND (Electronic Nicotine Delivery Systems OR Vaping)

Characteristics of studies

Characteristics of excluded studies [ordered by study ID]

Study	Reason for exclusion
Abdul Halim 2022	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Acosta 2020	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
ACTRN12618001509257	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
ACTRN12620000790943	Inappropriate intervention – did not specifically target e‐cigarettes
ACTRN12622001087741	Inappropriate intervention – did not specifically target e‐cigarettes
Bailey 2013	Inappropriate intervention – did not specifically target e‐cigarettes
Blitchtein‐Winicki 2017	Inappropriate intervention – did not specifically target e‐cigarettes
Bonell 2020	Inappropriate intervention – did not specifically target e‐cigarettes
Brown 2019	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Bteddini 2023	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Cartujano‐Barrera 2022a	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Cartujano‐Barrera 2022b	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Chaffee 2023	Inappropriate study design – not a randomised controlled trial
Chu 2021a	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Chu 2021b	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Conner 2020	Inappropriate intervention – did not specifically target e‐cigarettes
Coulter 2019	Inappropriate outcomes – follow‐up period was less than 3 months
De La Garza 2019	Inappropriate study design – not a randomised controlled trial
England 2021	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Farrelly 2015	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Graham 2021	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
Hamilton 2007	Inappropriate intervention – did not specifically target e‐cigarettes
Haug 2020	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Haug 2022	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
ISRCTN14023111	Inappropriate intervention – did not specifically target e‐cigarettes
ISRCTN14041907	Inappropriate study design – not a randomised controlled trial
ISRCTN85812512	Inappropriate intervention – did not specifically target e‐cigarettes
Kelder 2020	Inappropriate study design – not a randomised controlled trial
Kelder 2021	Inappropriate study design – not a randomised controlled trial
Kim 2019	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Kimber 2020	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
Kowitt 2022	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Liu 2021	Inappropriate study design – not a randomised controlled trial
Maloney 2016	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
Merrill 2022	Inappropriate study design – not a randomised controlled trial
Moulier 2019	Inappropriate study design – not a randomised controlled trial
Mungia 2021	Inappropriate study design – not a randomised controlled trial
NCT02500238	Inappropriate study design – not a randomised controlled trial
NCT02949648	Inappropriate study design – not a randomised controlled trial
NCT03168191	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
NCT03249428	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
NCT03480373	Inappropriate study design – not a randomised controlled trial
NCT03634839	Inappropriate intervention – did not target e‐cigarettes prevention or cessation
NCT03682900	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
NCT03690427	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
NCT03786042	Inappropriate outcomes – follow‐up period was less than 3 months
NCT03815591	Inappropriate study design – not a randomised controlled trial
NCT04083469	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
NCT04140617	Inappropriate study design – not a randomised controlled trial
NCT04249219	Inappropriate study design – not a randomised controlled trial
NCT04395274	Inappropriate study design – not a randomised controlled trial
NCT04416698	Inappropriate study design – not a randomised controlled trial
NCT04602494	Abstract or trial registration only – full text could not be identified
NCT04616313	Inappropriate study design – not a randomised controlled trial
NCT04661683	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
NCT04662658	Inappropriate study design – not a randomised controlled trial
NCT04772014	Inappropriate study design – not a randomised controlled trial
NCT04836455	Inappropriate outcomes – follow‐up period was less than 3 months
NCT04867668	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
NCT04879225	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
NCT04891939	Inappropriate intervention – did not specifically target e‐cigarettes
NCT04951193	Inappropriate outcomes – follow‐up period was less than 3 months
NCT04972513	Inappropriate study design – not a randomised controlled trial
NCT04982978	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
NCT05105555	Inappropriate study design – not a randomised controlled trial
NCT05120466	Inappropriate study design – not a randomised controlled trial
NCT05207033	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
NCT05240027	Inappropriate study design – not a randomised controlled trial
NCT05430334	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
NCT05458895	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
NCT05477888	Inappropriate study design – not a randomised controlled trial
NCT05482581	Inappropriate study design – not a randomised controlled trial
NCT05488743	Inappropriate study design – not a randomised controlled trial
NCT05604508	Inappropriate outcomes – follow‐up period was less than 3 months
NCT05669716	Inappropriate study design – not a randomised controlled trial
NCT05751369	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
Noar 2020	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Noar 2022	Inappropriate outcomes – follow‐up period was less than 3 months
Okamoto 2019	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Padon 2018	Inappropriate outcomes – did not include eligible measure of e‐cigarette use
Palmer 2022	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
Pentz 2016	Inappropriate study design – not a randomised controlled trial
Ramos 2022	Inappropriate study design – not a randomised controlled trial
Schwinn 2019	Inappropriate intervention – did not specifically target e‐cigarettes
Soria 2006	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
Taylor 2023	Inappropriate study design – not a randomised controlled trial
Walter 2019	Inappropriate participants – study did not include participants with a mean age of 19 years or younger
Zhao 2023	Inappropriate outcomes – follow‐up period was less than 3 months

Characteristics of ongoing studies [ordered by study ID]

ACTRN12623000079640.

Study name	Efficacy of a text‐message based intervention in preventing adolescent e‐cigarette use
Methods	Study aim: To examine the potential effect of a text‐message‐based intervention on preventing adolescent e‐cigarette use Study design: Randomised controlled trial
Participants	Setting: Home Type of participants: Parent‐adolescent dyads Age range of participants (if children or adolescents): Adolescents aged between 12 and 15 years Region: Australia
Interventions	Number of experimental conditions: 4 (3 intervention, control) Type of intervention: Prevention Description of intervention: Adolescent text‐messages: Adolescents from the parent‐adolescent dyads allocated to Group 1 will receive a theory‐based intervention to prevent adolescent e‐cigarette use lasting up to 2 years. Messages will be sent to adolescents to target factors (i.e. barriers and enablers) associated with adolescent e‐cigarette use, aligned to each of the Theory of Triadic Influence domains. Adolescents will receive 1 message per week for 9 to 10 weeks across a school term. Following this, adolescents will receive 1 booster message per term, resulting in 12 messages total per year. Parents from the parent‐adolescent dyads allocated to Group 1 will not receive the parent text‐messages; however, they will receive an evidence‐based e‐cigarette factsheet developed by NSW Health to educate parents on the risks associated with child and adolescent e‐cigarette use. Parent text‐messages: Parents from the parent‐adolescent dyads allocated to Group 2 will receive a theory‐based intervention to prevent adolescent e‐cigarette use lasting up to 2 years. Messages will be sent to parents to target factors associated with adolescent e‐cigarette use that could be influenced by parents, such as adolescent accessibility and exposure to e‐cigarettes, role of parents as a positive support mechanism, parent knowledge and perceptions of harms regarding adolescent e‐cigarette use. Parents will receive 1 message per week for 9 to 10 weeks across a school term. Following this, parents will receive 1 booster message per term, resulting in 12 messages total per year. Adolescents from the parent‐adolescent dyads allocated to Group 2 will not receive the adolescent text‐messages during the intervention period. Parent and adolescent text‐messages: Parent‐adolescent dyads randomly allocated to Group 3 will receive both the parent and adolescent text‐messages described above. Parents will also receive the e‐cigarette factsheet. Comparator: Parents in the parent‐adolescent dyads allocated to the control group will receive the e‐cigarette factsheet described above. Adolescents will not receive anything.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Adolescent ever‐use of e‐cigarettes, defined as any lifetime use of e‐cigarettes, will be assessed via an online or telephone survey conducted by a trained research assistant. Secondary: Outcomes relating to child and adolescent use of tobacco Adolescent tobacco use will be assessed via an online or telephone survey conducted by a trained research assistant. As recommended by the World Health Organization to measure youth tobacco use, survey items include ever‐use of cigarettes (defined as lifetime use, including 1 or 2 puffs) and the current use (defined as use in the past 30 days) of other forms of tobacco, including cigars, pipes, and smokeless tobacco. Adolescents that report ever‐use of cigarettes will be asked additional survey items including age of cigarette smoking initiation and current use of cigarettes (defined as use in the past 30 days). Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	Date registered: 25 January 2023 Anticipated date of first enrolment: 1 February 2023
Contact information	Dr Courtney Barnes; courtney.barnes@health.nsw.gov.au
Notes	Trial registration: ACTRN12623000079640. This trial replaced previously registered trials (ACTRN12622000901707p and ACTRN12622000905763p), which were initially identified in the trial registry search. Data availability: The review team contacted the principal investigator (PI) to obtain available data to include in the review. The PI indicated that no data were currently available.

Brinker 2016.

Study name	Photoaging smartphone app promoting poster campaign to reduce smoking prevalence in secondary schools: The Smokerface Randomized Trial: Design and baseline characteristics
Methods	Study aim: To evaluate its effectiveness regarding smoking prevalence and students’ attitudes towards smoking. Study design: Randomised controlled trial
Participants	Setting: School Type of participants: Secondary school students in grade 6 or 7 who are ever‐smokers and never‐smokers Age range of participants (if children or adolescents): Mean age of intervention group 12.01 years (SD 0.86); mean age of control group 11.98 years (SD 0.84) Region: Germany
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention and cessation Description of intervention: Intervention: Students allocated into the intervention condition were exposed to a posters campaign in their classrooms advertising the free selfie photoaging app “Smokeface” which shows the short‐term and long‐term effects of smoking. Comparator: Students in the control groups were not exposed to the poster campaign in their classrooms.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use The primary endpoint is defined as the difference of the change in smoking prevalence from baseline to 24‐month follow‐up between the 2 groups. Secondary: Outcomes relating to child and adolescent use of tobacco The primary endpoint is defined as the difference of the change in smoking prevalence from baseline to 24‐month follow‐up between the 2 groups. Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	2016
Contact information	Titus J Brinker; brinker@uk‐essen.de
Notes	Trial registration: NCT02544360 DOI: 10.18332/tid/83775 Data availability: The review team contacted the corresponding author to obtain available data to include in the review. No information was provided.

Gardner 2023.

Study name	Study protocol of the Our Futures Vaping Trial: a cluster randomised controlled trial of a school‐based eHealth intervention to prevent e‐cigarette use among adolescents
Methods	Study aim: To evaluate the efficacy of a school‐based eHealth intervention to prevent e‐cigarette use amongst adolescents Study design: Cluster‐randomised controlled trial
Participants	Setting: School Type of participants: Secondary school students Age range of participants (if children or adolescents): Adolescents aged between 11 and 15 years Region: Australia
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention Description of intervention: Intervention: The OurFutures Vaping Program is a universal school‐based eHealth prevention programme that aims to prevent the uptake, and reduce the use, of e‐cigarettes amongst adolescents. The program is built on the effective “OurFutures” (formerly “Climate Schools”) prevention model which is based on social influence and social competence principles. The OurFutures Vaping Program aligns with the Australian and state‐based Health and Physical Education Curriculums and is designed to be delivered during Year 7/8 health education classes. The programme consists of 4 x 40‐minute lessons (delivered 1 week apart over 4 weeks) consisting of a web‐based cartoon component completed individually by students (approx 20 min), followed by optional teacher‐facilitated activities (e.g. quizzes, class discussions, role plays). Comparator: Schools allocated to the control condition will implement health education as usual in their Health and Physical Education lessons. As drug education is mandatory within the Australian health education curriculum, these schools serve as an ‘active control’. A logbook will be completed by teachers at control schools to understand the amount and format of e‐cigarette or tobacco cigarette education delivered to their Year 7/8 students. Control schools will be offered access to the intervention at the end of the study.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Uptake of e‐cigarette use. Assessed using a single item: “Have you ever used a vape, even one or two puffs?” (Yes/No). Measured at baseline, post‐test (post‐completion of 4‐week intervention), 6‐, 12‐, 24‐, and 36‐month follow‐up. The primary time point is 12 months. Secondary: Outcomes relating to child and adolescent use of tobacco Uptake of tobacco cigarette use. Assessed using a single item: “Have you ever tried smoking a cigarette, even one or two puffs?” (Yes/No). Measured at baseline, post‐test (post‐completion of 4‐week intervention), 6‐, 12‐, 24‐, and 36‐month follow‐up. Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	Date registered: 10 January 2023 Anticipated date of first enrolment: 24 April 2023
Contact information	Lauren Gardner; Lauren.gardner@sydney.edu.au
Notes	DOI: 10.1186/s12889‐023‐15609‐8 Trial registration: ACTRN12623000022662 Data availability: The review team contacted the research team to obtain available data to include in the review. The research team indicated that recruitment of schools has commenced and is ongoing.

Little 2022.

Study name	Rationale, design, and methods for the development of a youth adapted Brief Tobacco Intervention plus automated text messaging for high school students
Methods	Study aim: To develop and pilot test a universal group‐based Youth Brief Tobacco Intervention (Y‐BTI) plus mobile phone automated text messaging (ATM) for 9th grade students to both prevent initiation amongst non‐users and promote cessation amongst current‐users Study design: Cluster‐randomised controlled trial
Participants	Setting: School Type of participants: 9th grade students Age range of participants (if children or adolescents): 14 to 15 years Region: Virginia, USA
Interventions	Number of experimental conditions: 4 (3 intervention, 1 control) Type of intervention: Prevention and cessation Description of intervention: Intervention: Youth Brief Tobacco Intervention. The universal prevention programme was designed as a group intervention to include components of effective tobacco control programmes for youth and young adults. The intervention lasts approximately 45 minutes and is delivered in a classroom setting, utilising a Socratic teaching style and evoking participation using the principles of motivational interviewing. The Y‐BTI targets all tobacco products with the goals to enhance motivation for youth to quit tobacco or remain tobacco‐free, reduce intentions to use tobacco, promote peer discussions around the impact of using tobacco, and correct cognitive misperceptions around tobacco use. Intervention: Automated Text Messaging. The ATM intervention is automated because all messages are pre‐written, and their timing is pre‐planned. Therefore, all students will receive the same content at the same time. The ATM intervention will last 4 weeks, with 3 to 5 messages sent per week. The automated programme will include a mix of static and responsive messages. Specifically, some messages will be designed to maintain or enhance knowledge about tobacco use by providing facts to the student, for example listing the negative health effects of tobacco use. Other messages will promote engagement and reflection from the student. Intervention: Youth Brief Tobacco Intervention + Automated Text Messaging Comparator: No‐treatment control
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Past 30‐day point prevalence abstinence at 28‐week follow‐up. The primary outcome measure in this study is self‐reported past 30‐day abstinence from e‐cigarettes. Secondary: Outcomes relating to child and adolescent use of tobacco Past 30‐day point prevalence abstinence at 28‐week follow‐up. The primary outcome measure in this study is self‐reported past 30‐day abstinence from cigarettes, e‐cigarettes, smokeless tobacco, hookah, cigars, little cigars, cigarillos, and pipe tobacco. Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 31 May 2022 Estimated study completion date: 30 June 2024
Contact information	Melissa A Little; mal7uj@virginia.edu
Notes	DOI: 10.1016/j.cct.2022.106840 Data availability: The review team contacted the corresponding author to obtain available data to include in the review. The author indicated that no data were currently available.

Lyu 2022.

Study name	Delivering vaping cessation interventions to adolescents and young adults on Instagram: protocol for a randomized controlled trial
Methods	Study aim: To test the efficacy of an Instagram‐based vaping cessation intervention for adolescents and young adults Study design: Randomised controlled trial
Participants	Setting: Home Type of participants: Adolescents and young adults who have vaped at least once in the past 30 days, and are considering quitting or are interested in quitting Age range of participants (if children or adolescents): 13 to 21 years Region: California, USA
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Cessation Description of intervention: Intervention: The vaping intervention will be implemented on Instagram. Participants in the treatment condition will be assigned to groups on Instagram, where they will receive up to 3 posts per day for 30 days. Groups are facilitated by a trained Guide, working with the Principal Investigator, Co‐Investigators, and a Paediatrician on demand if additional expertise or clinical advice is needed. Participants will be educated about signs of nicotine dependence, and if they express interest in pharmacotherapy will be encouraged to access this through their personal healthcare providers. The Instagram groups will provide educational and social support, troubleshooting, and advice about nicotine replacement therapy (NRT) or other forms of treatment. Comparator: Participants in the control condition will be directed to the Truth Initiative e‐cigarette texting quit programme.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Point Prevalent Abstinence (PPA) from vaping [Time Frame: 1, 3, and 6 months]. 7‐day point prevalence abstinence (PPA) from all tobacco products will be assessed over the course of the study. Participants reporting no vaping in the past 7 days will be coded as abstinent. Those reporting 7‐day abstinence and not using nicotine replacement therapy will be mailed saliva cotinine test kit and saliva tetrahydrocannabinol (THC) test kit for biochemical verification of abstinence. Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	10 December 2022
Contact information	Pamela M Ling; Pamela.ling@ucsf.edu.au or Sarah Rosen; quitthehit@ucsf.edu
Notes	DOI: 10.1186/s12889‐022‐14606‐7 Trial registration: NCT04707911 Data availability: The review team contacted the corresponding author to obtain available data to include in the review. The author indicated that no data were currently available.

NCT04040153.

Study name	Guiding Good Choices for Health
Methods	Study aim: To test Guiding Good Choices effectiveness with respect to improving adolescent behavioural health outcomes when implemented at scale in paediatric primary care within a pragmatic trial Study design: Cluster‐randomised controlled trial
Participants	Setting: Health service Type of participants: Parents of adolescents assigned to a paediatrician in a participating clinic in 1 of the 3 healthcare systems Age range of participants (if children or adolescents): Parents of adolescents aged 11 to 12 years Region: USA
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention Description of intervention: Intervention: Guiding Good Choices is a 5‐session group‐based prevention programme for parents of early adolescents. Weekly 2.5‐hour sessions will be held at participants' primary care clinics and led by 2 trained interventionists. Through didactic material, video segments, interactive activities, and home practice, the curriculum teaches parents to understand the progression from individual and environmental risk and protective factors to substance use and problem behaviour, enhances parenting behaviours and skills, teaches effective family management skills, strengthens parent‐adolescent interactions and bonding, broadens opportunities for family involvement, teaches conflict reduction and anger management skills, and teaches adolescents skills to resist peer influences to engage in risky behaviour. Comparator: Parents of adolescents will not be offered Guiding Good Choices.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Incidence of adolescent e‐cigarette use initiation through last follow‐up [Time Frame: Final follow‐up in year 5 of study] Prevalence of any past‐year and past 30‐day e‐cigarette use by adolescents at final follow‐up [Time Frame: 3‐year follow‐up (cohort 1), 2‐year follow‐up (cohort 2) assessments] Secondary: Outcomes relating to child and adolescent use of tobacco Incidence of adolescent cigarette use initiation through last follow‐up [Time Frame: Final follow‐up in year 5 of study] Prevalence of any past‐year and past 30‐day cigarette use by adolescents at final follow‐up [Time Frame: 3‐year follow‐up (cohort 1), 2‐year follow‐up (cohort 2) assessments] Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 31 July 2019 Estimated study completion date: 31 May 2023
Contact information	Diane Christiansen; dianech@uw.edu
Notes	Trial registration: NCT04040153 Data availability: The review team contacted the PI to obtain available data to include in the review. No information was provided.

NCT04054765.

Study name	A Virtual Reality Videogame for E‐cigarette Prevention in Teens
Methods	Study aim: To determine the preliminary impact of the intervention on e‐cigarette use behaviours, knowledge, nicotine addiction knowledge, perceived addictiveness of e‐cigarettes, perceived likelihood of using e‐cigarettes, perceptions of harm, self‐efficacy to refuse, social approval of e‐cigarettes, and e‐cigarette social perceptions Study design: Randomised controlled trial
Participants	Setting: School Type of participants: Adolescents Age range of participants (if children or adolescents): 11 to 15 years Region: USA
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention Description of intervention: Intervention: Participants will accumulate between 1.5 and 2 hours of game play over 2 sessions. Participants will play the Invite Only VR game on a VR headset for 45 min to 1 hour, 1 to 2 times per week for 2 weeks (to accumulate up to 1.5 to 2 hours of gameplay). This total duration and number of sessions is consistent with those found in effective smoking prevention interventions amongst adolescents and with the amount of time adolescents play video games. Comparator: Standard care
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Proportion of participants who report e‐cigarette use at 6 months [Time Frame: 6 months] Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	January 2020
Contact information	Kimberly Hieftje, no email provided
Notes	Trial registration: NCT04054765 Data availability: The review team contacted the PI to obtain available data to include in the review. No information was provided.

NCT04146714.

Study name	Substance Use Screening to Encourage Behavior Change Among Young People in Primary Care (YP‐HEALTH)
Methods	Study aim: To evaluate whether completing a short screening questionnaire about health behaviours in the waiting room before a primary care consultation decreases excessive substance use in young people aged 14 to 24 years Study design: Randomised controlled trial
Participants	Setting: Health service Type of participants: Adolescents and adults consulting at the participating primary care practice for any motive Age range of participants (if children or adolescents): 14 to 24 years Region: Switzerland
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention and cessation Description of intervention: Intervention: Young people consulting a primary care physician will receive a questionnaire about substance use. Comparator: Young people consulting a primary care physician will receive a questionnaire about physical activity.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Proportion of participants reporting electronic cigarette use at least once per day in the last 30 days. [Time Frame: 3, 6, and 12 months]. Patient self‐report on follow‐up telephone questionnaire Secondary: Outcomes relating to child and adolescent use of tobacco Proportion of participants reporting smoking at least once per day in the last 30 days. [Time Frame: 3, 6, and 12 months]. Patient self‐report on follow‐up telephone questionnaire Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 31 October 2019 Estimated study completion date: December 2026
Contact information	Dagmar M Haller; dagmar.haller‐hester@unige.ch
Notes	Trial registration: NCT04146714 Source: https://clinicaltrials.gov/show/NCT04146714 Data availability: The review team contacted the PI to obtain available data to include in the review. The author indicated that no data were currently available.

NCT04678245.

Study name	Network Intervention to Prevent Vaping
Methods	Study aim: The primary aim of this study is to determine ‘Above the Influence of Vaping’ (ATI‐V) impact in preventing vaping use. 20 schools will be assigned to (a) immediate ATI‐V, or (b) waitlist for ATI‐V training after 24 months. Study design: Randomised controlled trial
Participants	Setting: School Type of participants: 8th and 9th grade students Age range of participants (if children or adolescents): 12 to 18 years Region: Not explicitly reported
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention Description of intervention: Intervention: Above the Influence of Vaping (ATI‐V) trains peer‐nominated 8th‐9th grade Peer Leader, and adult advisors. Peer Leaders learn skills and implement school‐wide prevention campaigns informed by communication science. Comparator: Waitlist for ATI‐V training after 24 months
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Number of participants with any past 30‐day vaping [Time Frame: 28 months]. Self‐report of e‐cigarette use of any kind in the past 30 days Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 21 December 2020 Estimated study completion date: 28 February 2024
Contact information	Not available
Notes	Trial registration: NCT04678245 Data availability: Contact information was not available for PI to obtain data to include in the review.

NCT04843501.

Study name	Middle School Cluster Randomized Controlled Trial (RCT) to Evaluate E‐Cigarette Prevention Program: CATCH My Breath
Methods	Study aim: to evaluate the effectiveness of an e‐cigarette curriculum (called the CATCH My Breath (CMB) programme) in delaying the onset of e‐cigarette use in middle schoolers Study design: Randomised controlled trial
Participants	Setting: School Type of participants: Students in the 6th, 7th, and 8th grades Age range of participants (if children or adolescents): 10 to 15 years Region: Texas, USA
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention and cessation Description of intervention: Intervention: Schools will be assigned to the CMB programme. The CMB curriculum is divided into 4 developmentally appropriate e‐cigarette lessons (approximately 20 to 30 minutes each) for middle school‐aged youth (6th to 8th grade). A variety of educational strategies are used and include co‐operative learning groups, large group discussions, interviews, role‐play, media, reports, and goal‐setting. Comparator: Schools will be assigned to usual care, which is Texas Education Agency (TEA) required tobacco prevention programme. The TEA tobacco prevention programme is a state‐supported programme that meets the mandates of the state. It includes online lessons and support materials. Both programmes will be administered to participating students over 3 years.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Number of students who currently use e‐cigarettes [Time Frame: baseline, 3 years]. Current use is defined as e‐cigarette use in the last 30 days. Number of students who have ever used e‐cigarettes in their lifetime [Time Frame: baseline, 3 years] Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 13 April 2021 Estimated study completion date: 1 March 2024
Contact information	Steven H Kelder; Steven.H.Kelder@uth.tmc.edu
Notes	Trial registration: NCT04843501 Data availability: The review team contacted the PI to obtain available data to include in the review. The author indicated that no data were currently available.

NCT04898075.

Study name	Quit Nicotine: e‐Cig Cessation Intervention
Methods	Study aim: To examine the feasibility, acceptability, and efficacy of web‐based, remote Contingency Management (CM) for nicotine abstinence plus individualised Cognitive Behavioural Therapy (CBT) amongst youth e‐cigarette users Study design: Randomised controlled trial
Participants	Setting: Home Type of participants: Adolescent high school students who are regular users of e‐cigarettes containing nicotine Age range of participants (if children or adolescents): 13 to 19 years Region: Not explicitly reported
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Cessation Description of intervention: Intervention: Participants will take part in a 4‐week‐long Remote Contingency Management (Remote CM) intervention that involves the delivery of CM procedures using tablets, weekly vaping cessation CBT sessions, and follow‐up appointments at 1, 3, 6, and 12 months. Participants will be paid increasing amounts of payment for each negative saliva cotinine test. Comparator: Participants will be paid for providing saliva nicotine test, regardless of whether the test is positive or negative.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Change in 7‐day point prevalence abstinence [Time Frame: 1, 3, 6, and 12 months]. Self‐reported of no e‐cigarette usage during the 7 days prior and confirmed negativity with cotinine levels of 30 ng/mL (Alere iScreen OFD Cotinine Saliva Test; Countrywide Testing) Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 24 May 2021 Estimated study completion date: June 2024
Contact information	Suchitra Krishnan‐Sarin; suchitra.krishnan‐sarin@yale.edu
Notes	Trial registration: NCT04898075 Data availability: The review team contacted the PI to obtain available data to include in the review. The author indicated that no data were currently available.

NCT04919590.

Study name	Text Message Quit Vaping Intervention for Adolescents
Methods	Study aim: To evaluate the effectiveness of a quit‐vaping text‐message programme in promoting abstinence from e‐cigarettes amongst young users aged 13 to 17 Study design: Randomised controlled trial
Participants	Setting: Home Type of participants: Adolescents who used e‐cigarettes containing nicotine in the past 30 days and have an interest in quitting e‐cigarette use in the next 30 days Age range of participants (if children or adolescents): 13 to 17 years Region: USA
Interventions	Number of experimental conditions: 3 (intervention, 2 control) Type of intervention: Cessation Description of intervention: Intervention: Participants will be enrolled to receive messages from This is Quitting. Users receive 1 age‐appropriate message per day tailored to their enrolment date or quit date, which can be set and reset via text‐message. Those not ready to quit receive 4 weeks of messages focused on building skills and confidence. Users who set a quit date receive messages for a week preceding it and 8 weeks afterward that include encouragement and support, skill‐ and self‐efficacy building exercises, coping strategies, and information about the risks of vaping, benefits of quitting, and cutting down to quit. Keywords COPE, STRESS, SLIP, and MORE provide on‐demand support. Assessment‐only control: After an initial enrolment message, participants will be contacted monthly to assess e‐cigarette use. At the end of the study data collection period, they will receive information on how to sign up for This is Quitting if they are interested in the programme. Waitlist control: After an initial enrolment message, participants will receive no contact from study staff except for 1‐ and 7‐month follow‐up assessments. At the end of the study data collection period, they will receive information on how to sign up for This is Quitting if they are interested in the programme.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Self‐reported 30‐day Point Prevalence Abstinence [Time Frame: 7 months postenrolment]. Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 9 June 2021 Estimated study completion date: 15 October 2023
Contact information	Director of Research, Innovations; vapestudy@truthinitiative.org
Notes	Trial registration: NCT04919590 Data availability: The review team contacted the PI to obtain available data to include in the review. The author indicated that no data were currently available.

NCT05037656.

Study name	Testing a School‐Based E‐cigarette, Tobacco, and Betel (Areca) Nut Use Prevention Curriculum for Guam Youths
Methods	Study aim: To develop a school‐based curriculum for e‐cigarette, tobacco product (i.e. cigarette, smokeless tobacco), and betel nut use prevention amongst middle school students in Guam; and to test the efficacy of the school‐based curriculum in a randomised controlled trial Study design: Randomised controlled trial Testing a School‐Based E‐cigarette, Tobacco, and Betel (Areca) Nut Use Prevention Curriculum for Guam Youths
Participants	Setting: School Type of participants: Adolescents enrolled in public middle schools Age range of participants (if children or adolescents): 11 to 15 years Region: Guam, USA
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention Description of intervention: Intervention: Students in the treatment group will receive the school‐based classroom curriculum. The curriculum will be implemented using 5 intensive in‐class lessons over the span of 6 weeks. All sessions of the curriculum follow the same basic format: a) an introduction and/or review of the past lesson, b) a cultural wall activity, c) a video, d) 1 to 2 interactive activities, and e) a wrap‐up activity. Lessons are designed to help improve knowledge about drugs and correct cognitive misperceptions and to train skills to resist normative social influence. Comparator: Students in the control group will receive the standard health education curriculum.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Changes in Youth Risk Behavior Surveillance (YRBS) Survey‐based self‐reported past‐30‐day tobacco, e‐cigarette, and areca nut use [Time Frame: Outcomes will be assessed at baseline (pre‐test), 5 weeks after baseline, immediately following curriculum/standard of care delivery (i.e. post‐test), and 6 months after baseline (follow‐up)]. E‐cigarette use behaviour will be assessed using a standardised self‐report measure of recent use that is used in the national YRBS survey. Secondary: Outcomes relating to child and adolescent use of tobacco Changes in Youth Risk Behavior Surveillance (YRBS) Survey‐based self‐reported past‐30‐day tobacco, e‐cigarette, and areca nut use [Time Frame: Outcomes will be assessed at baseline (pre‐test), 5 weeks after baseline, immediately following curriculum/standard of care delivery (i.e. post‐test), and 6 months after baseline (follow‐up)]. Tobacco use behaviour will be assessed using a standardised self‐report measure of recent use that is used in the national YRBS survey. Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 8 September 2021 Estimated study completion date: August 2023
Contact information	Francis Dalisay; fdalisay@triton.uog.edu
Notes	Trial registration: NCT05037656 Data availability: The review team contacted the PI to obtain available data to include in the review. No information was provided.

NCT05081843.

Study name	Pittsburgh and Rural Area High School Tobacco Prevention
Methods	Study aim: To explore the feasibility and acceptability of a web‐based media literacy tobacco prevention programme Study design: Randomised controlled trial
Participants	Setting: School Type of participants: 9th grade students enrolled at participating Pittsburgh‐area school Age range of participants (if children or adolescents): Adolescents aged 13 to 17 years Region: Pittsburgh, USA
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention Description of intervention: Intervention: AD IT UP media literacy intervention and usual health education curriculum. AD IT UP was originally developed in 2006 as a classroom‐based cigarette prevention programme focused on traditional media influences and was converted to a web‐based programme in 2011. In 2019, the AD IT UP programme was updated substantially to include other forms of tobacco, such as e‐cigarettes, and other forms of media, such as social media. Comparator: Usual health education curriculum. The schools' regular health education curriculum includes classroom lectures, hands‐on activities, and group work.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Unclear if e‐cigarette use as an outcome has been included Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 18 October 2021 Estimated study completion date: June 2023
Contact information	Not available
Notes	Trial registration: NCT05081843 Data availability: The review team contacted the PI to obtain available data to include in the review. No information was provided.

NCT05140915.

Study name	Vaper to Vaper: a Multimodal Mobile Peer Driven Intervention to Support Adolescents in Quitting Vaping
Methods	Study aim: To develop Vaper‐to‐Vaper (V2V), a suite of mobile peer‐driven tools including peer texting and coaching based on lessons learnt in the investigators' prior tobacco intervention work, to engage and help adolescents use strategies to manage cravings and successfully quit Study design: Randomised controlled trial
Participants	Setting: School Type of participants: Adolescents enrolled in grades 9 to 12 at participating high school Age range of participants (if children or adolescents): 13 to 19 years Region: Not explicitly reported
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Cessation Description of intervention: Intervention: Students in school randomised to the intervention will receive: (1) peer messages, written by current and former adolescent e‐cigarette users and tailored by age and readiness‐to‐quit; (2) peer coaching, facilitated by texting; and (3) gamification, designed to motivate participation. Comparator: Students in schools randomised to the control condition will be provided written e‐cigarette cessation materials by the Research Coordinator at the time of study enrolment. The written materials will consist of 2 pamphlets from Journeyworks, selected based on: (1) their clear and attractive layout designed for a low‐literacy audience, and (2) their providing both information regarding e‐cigarette use with a strong message about nicotine and nicotine addiction, E‐Cigarettes: 8 Things Everyone Should Know, and support in quitting, How to Quit Vaping.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Abstinence from vaping as measured by saliva samples [cotinine‐validated 7‐day point prevalence] [Time Frame: 6 months]. Cotinine‐validated 7‐day point prevalence abstinence, as measured by saliva samples collected from all; analysed for those reporting 7‐day abstinence; cut‐off 11.4 ng/mL, cotinine‐imputed abstinence when cotinine is missing Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 2 December 2021 Estimated study completion date: 30 April 2023
Contact information	Dante Simone; dante.simone@umassmed.edu
Notes	Trial registration: NCT05140915 Data availability: The review team contacted the PI to obtain available data to include in the review. No information was provided.

NCT05219422.

Study name	Testing ALERT With GTO in Middle Schools (GTO‐ALERT)
Methods	Study aim: To test the efficacy of Project ALERT with the support enhancement tool, Getting To Outcomes Study design: Randomised controlled trial
Participants	Setting: School Type of participants: Students in 7th grade, primarily aged 12 to 14 years Age range of participants (if children or adolescents): 11 to 16 years Region: USA
Interventions	Number of experimental conditions: 3 (2 intervention, control) Type of intervention: Prevention Description of intervention: Intervention: Schools will receive Project ALERT only for 3 years starting fall 2022. Project ALERT includes a 14‐session drug prevention programme for 7th and 8th grade youth. Intervention: Schools will receive Project ALERT plus Getting To Outcomes for 3 years starting fall 2022. The Getting To Outcomes (GTO) implementation support intervention provides technical assistance, training, guides, and tools to improve community‐based practitioners' capacity to complete tasks associated with implementing an evidence‐based programme, which in turn leads to improved implementation fidelity. Comparator: Schools will receive neither Project ALERT nor Project ALERT plus GTO until year 3 of the study.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Changes in student alcohol and drug behaviour [Time Frame: Changes assessed for past year use at each follow‐up point from baseline] Secondary: Outcomes relating to child and adolescent use of tobacco Changes in student alcohol and drug behaviour [Time Frame: Changes assessed for past year use at each follow‐up point from baseline] Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 2 February 2022 Estimated study completion date: October 2026
Contact information	Matthew Chinman; chinman@rand.org
Notes	Trial registration: NCT05219422 Data availability: The review team contacted the PI to obtain available data to include in the review. No information was provided.

NCT05366790.

Study name	A Brief Digital Screening Tool to Address Tobacco and E‐cigarette Use in Paediatric Medical Care
Methods	Study aim: To perform a pilot randomised controlled trial of the Clinical Effort Against Second‐hand Smoke (CEASE) intervention in Canada Study design: Randomised controlled trial
Participants	Setting: Health service Type of participants: Parents with a child of 0 to 17 years and adolescents in Canada Age range of participants (if children or adolescents): Adolescents aged 14 to 17 years Region: Canada
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Cessation Description of intervention: Intervention: The CEASE and CEASE‐A interventions are tobacco and vaping cessation interventions delivered in paediatric practices, leveraging existing healthcare and community resources. They integrate evidence‐based tobacco use screening and cessation assistance into routine visits to paediatric clinics. CEASE and CEASE‐A are based on the 5A's model of smoking cessation: Ask about smoking, Advise to quit, Assess readiness to quit, Assist with a quit plan, and Arrange follow‐up. Given that CEASE and CEASE‐A are one‐time interventions, "Arrange" is removed, and the fourth step, "Assist", is divided into 2 parts: a) providing phone/text/app quit support; and b) providing nicotine replacement therapy. CEASE‐A follows the same format as CEASE, but is modified slightly to address smoking and vaping in the adolescent target population. Comparator: The control condition will be care as is usually delivered in participating clinics with the possibility of receiving direct linkage with cessation services delivered via CEASE/CEASE‐A at the end of the 6‐month study period. Current practice does not include routine provision of assistance for parental/adolescent smoking or e‐cigarette cessation.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Abstinence at 6 months [Time Frame: 6 months of participant follow‐up]. % of adolescent users who report 7‐day abstinence at 6‐month follow‐up. They will collect self‐reported vaping status using the validated single item "Have you used a nicotine vaping product, even a puff, in the past 7 days?". Cotinine‐confirmed quit [Time Frame: 6 months of participant follow‐up]. Participants who self‐report 7‐day abstinence at 1, 3, and/or 6 months will receive a sampling kit by mail along with instructions on how to collect the urine for biochemical confirmation of smoking/vaping cessation. Secondary: Outcomes relating to child and adolescent use of tobacco Participant self‐reported smoking cessation at 6‐month follow‐up. They will collect self‐reported smoking status using the validated single item "Have you smoked a single cigarette, even a puff, in the past 7 days?". Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 9 May 2022 Estimated study completion date: December 2025
Contact information	Tamara Perez; tamara.perez.hsj@ssss.gouv.qc.ca
Notes	Trial registration: NCT05366790 Data availability: The review team contacted the PI to obtain available data to include in the review. No information was provided.

NCT05367492.

Study name	Varenicline for Nicotine Vaping Cessation in Adolescents
Methods	Study aim: To test the hypothesis that varenicline, when added to group behavioural and texting support for vaping cessation, will improve vaping abstinence rates in adolescents dependent on vaped nicotine over placebo plus group behavioural and texting support for vaping cessation Study design: Randomised controlled trial
Participants	Setting: Health service Type of participants: Adolescents and adults who self‐report daily or near‐daily nicotine vaping for the prior ≥ 3 months and saliva screening for cotinine positive for recent nicotine use Age range of participants (if children or adolescents): 16 to 25 years Region: Not explicitly reported
Interventions	Number of experimental conditions: 3 (intervention, 2 control) Type of intervention: Cessation Description of intervention: Intervention: Double‐blind varenicline. Participants will receive the drug varenicline, in tablet form, up to 1 mg twice daily for 12 weeks; attend QuitVaping behavioural support sessions, completed in‐person or via video‐conferencing, once per week for 12 weeks; be encouraged to sign up for This Is Quitting (TIQ), a text‐message vaping cessation programme for adolescents. Comparator: Double‐blind placebo. Participants will receive placebo tablets, identical in appearance to varenicline, up to 1 mg twice daily for 12 weeks; attend QuitVaping behavioural support sessions, completed in‐person or via video‐conferencing, once per week for 12 weeks; be encouraged to sign up for This Is Quitting (TIQ), a text‐message vaping cessation programme for adolescents. Comparator: Single‐blind monitoring only. Participants will receive NO drug intervention; attend NO behavioural support sessions; will not be encouraged to sign up for text‐message vaping cessation support.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Continuous nicotine vaping abstinence over study weeks 9 to 24 [Time Frame: Study weeks 9, 10, 11, 12, 16, 20, 24]. Per cent of participants who self‐report nicotine vaping abstinence since the last visit and have cotinine < 10 ng/mL, assessed at each visit during study weeks 9 to 24 Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 10 May 2022 Estimated study completion date: December 2025
Contact information	Gladys N Pachas; gpachas1@mgh.harvard.edu
Notes	Trial registration: NCT05367492 Data availability: The review team contacted the PI to obtain available data to include in the review. No information was provided.

NCT05493982.

Study name	Evaluation of the Be Vape Free Curriculum of the Tobacco Prevention Toolkit
Methods	Study aim: To determine whether the Be Vape Free curriculum is effective in increasing middle and high school students' resistance to using tobacco and in decreasing positive attitudes towards and intentions to use e‐cigarettes Study design: Randomised controlled trial
Participants	Setting: School Type of participants: Middle and high school students Age range of participants (if children or adolescents): 10 to 20 years Region: Not explicitly reported
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention Description of intervention: Intervention: Schools receive the Stanford vaping prevention curriculum. The Stanford Tobacco Prevention Toolkit is a free online curriculum developed for use by educators and health professionals in providing tobacco‐specific prevention education to middle and high school students. The Be Vape Free curriculum is a set of lessons focused on e‐cigarette/vaping prevention education specifically. Comparator: Receives another curriculum or no vaping prevention education
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Change in e‐cigarette use [Time Frame: Change from baseline to follow‐up at approximately 156 weeks]. Investigator‐originated survey measures (questions) assess ever e‐cigarette use and past 30‐day tobacco use. Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	First posted: 9 August 2022 Estimated study completion date: 31 August 2025
Contact information	David C Cash; dcash2@stanford.edu
Notes	Trial registration: NCT05493982 Data availability: The review team contacted the PI to obtain available data to include in the review. No information was provided.

Sanchez 2023.

Study name	Supporting Youth Vaping Cessation With the Crush the Crave Smartphone App: Protocol for a Randomized Controlled Trial
Methods	Study aim: To determine the effectiveness of the Crush the Crave app in supporting vaping cessation amongst youth recruited to the intervention arm via comparison with an assessment‐only control group Study design: Randomised controlled trial
Participants	Setting: Home Type of participants: Adolescents living in Canada who have used nicotine cigarettes in the previous 30 days Age range of participants (if children or adolescents): 16 to 29 years Region: Canada
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Cessation Description of intervention: Intervention: Using Crush the Crave application. Crush the Crave for vaping cessation enables users to customise a quit plan. As a tracker app, Crush the Crave monitors the amount of money saved and the number of vape‐free days since the user’s quit date. This savings calculator is one of the most significant changes in this version of Crush the Crave, which involved the conversion of the money saved based on the number of cigarettes smoked in a day to the money saved based on the number vape pods used in a week. The app also tracks cravings and vaping habits through a diary of vaping triggers that records when, where, and why vaping occurs. The app displays supportive messages and graphic images of encouragement in response to cravings and relapse, as well as direct links to evidence‐based resources, such as quitlines. Comparator: Assessment‐only control. At the end of the intervention period and following the last follow‐up assessment, participants will be invited to try the Crush the Crave app if interested.
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use 30‐day point prevalence at 3 months, operationalised as not having vapes (even a puff) in the last 30 days Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	27 January 2023
Contact information	Michael Chaiton; Michael.chaiton@camh.ca
Notes	DOI: 10.17605/OSF.IO/HMD87 Data availability: The review team contacted the corresponding author to obtain available data to include in the review. No information was provided.

Shin 2021.

Study name	Preventing e‐cigarette use among high‐risk adolescents: a trauma‐informed prevention approach
Methods	Study aim: To review current evidence with respect to how childhood trauma could increase risk for nicotine dependence and e‐cigarette use in adolescent populations. Furthermore, to describe the development, design, and implementation of Rise Above (RA), a randomised controlled trial of a trauma‐informed, e‐cigarette preventive intervention Study design: Cluster‐randomised controlled trial
Participants	Setting: Community Type of participants: Students attending urban middle school in the Mid‐Atlantic Region Age range of participants (if children or adolescents): 11 to 14 years Region: USA
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention Description of intervention: Intervention: RA invites 6 to 8 youth per group (ages 11 to 14) to participate in 14, 50‐minute sessions that are facilitated by trained instructors. The preventive intervention utilises evidence‐based substance use prevention strategies, including normative education and skill building on the topics of awareness, coping, and resistance. Comparator: Not explicitly reported
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use E‐cigarette use (time point and data collection method not reported) Secondary: Outcomes relating to child and adolescent use of tobacco Not reported Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	24 December 2020
Contact information	Sunny H Shin; sshin@vcu.edu
Notes	DOI: 10.1016/j.addbeh.2020.106795 Data availability: The review team contacted the corresponding author to obtain available data to include in the review. No information was provided.

Steeger 2023.

Study name	Substance use prevention during adolescence: study protocol for a large‐scale cluster randomized trial of Botvin High School LifeSkills Training
Methods	Study aim: To test whether the programme High School LifeSkills Training (HS‐LST) is effective at preventing or reducing tobacco use and related problems Study design: Cluster‐randomised controlled trial
Participants	Setting: School Type of participants: 9th grade students from Colorado and Ohio schools Age range of participants (if children or adolescents): Not explicitly reported Region: Colorado and Ohio, USA
Interventions	Number of experimental conditions: 2 (intervention, control) Type of intervention: Prevention Description of intervention: Intervention: Teacher‐led intervention group running the HS‐LST, which strengthens students’ skills to avoid substances and other risk behaviours by providing prevention‐related information Comparator: Business‐as‐usual control group
Outcomes	Primary: Outcomes relating to the prevention or cessation of child and adolescent e‐cigarette use Self‐reported current‐use (past 30 days) of any nicotine products at 1‐year and 21‐month follow‐up Secondary: Outcomes relating to child and adolescent use of tobacco Self‐reported current‐use (past 30 days) of any nicotine products at 1‐year and 21‐month follow‐up Secondary: Outcomes relating to unintended adverse consequences of the intervention Not reported
Starting date	8 December 2022
Contact information	Christine M Steeger; christine.steeger@colorado.edu
Notes	DOI: 10.1016/j.cct.2022.107049 Data availability: The review team contacted the corresponding author to obtain available data to include in the review. No information was provided.

PI: Principal Investigator
SD: standard deviation

Differences between protocol and review

No differences to report.

Contributions of authors

CBa, LW, and SLY conceived the idea for this review. CBa, LW, SLY, RH, AH, and ES contributed to the methods for the protocol. CBa and CBi developed the search strategy for the review. CBa, RH, HT, SMc, and JM screened titles and abstracts and determined study eligibility. CBa and LW led the drafting of the manuscript. All authors provided support for manuscript drafting and provided critical comments and final approval for the manuscript.

Sources of support

Internal sources

• Deakin University, Australia

  Salary support for review authors

• University of Newcastle, Australia

  Salary support for review authors

• Hunter New England Population Health, Australia

  Salary support for review authors

• University of Sydney, Australia

  Salary support for review authors

External sources

• National Health and Medical Research Council (NHMRC), Australia

  This review was supported by funding from an NHMRC Centre for Research Excellence (No. APP1153479) – ‘the National Centre of Implementation Science’.
NHMRC also provides support for the editorial and author support function of Cochrane Public Health.

Declarations of interest

If a review author is also a contributor to a study that may be of interest to the review, that review author will not be involved in the determination of eligibility, data extraction, risk of bias assessment, and GRADE assessment. In such instances, these roles will be carried out by review authors who were not directly involved in these studies, in line with the Cochrane Conflict of Interests policy.

CBa: no interests declared.

HT: no interest declared.

SMc: SMc is Assistant Managing Editor and Method Editor for Cochrane Public Health, but has not been involved in the editorial process or assessment of this review. She has no interest to declare.

RH: no interests declared.

SLY: reports that she has published opinions in medical journals relevant to the interventions in the work. No other declarations of interest to report.

ES: reports that she has previously been contracted (paid to her institution) by the Australian Department of Health to provide a report on e‐cigarette use and trends in Australia to advise government policy, as well as contracted (paid to her institution) by the New South Wales Department of Health to assist in developing educational resources for young people regarding the risks of e‐cigarette use. ES has also published opinions in medical journals relevant to the interventions in the work.

AH: reports that she has undertaken relevant work for the World Health Organization (WHO). Activities included undertaking two systematic reviews: 1) prevalence of electronic nicotine delivery systems (ENDS)/electronic non‐nicotine delivery systems (ENNDS) use of youth; and 2) association between ENDS/ENNDS use and later tobacco uptake by youth. This work was administered to the University of Newcastle of which she is an employee. AH reports that she has published results from the work, which was conducted for the commissioned project by the WHO, in medical journals, and this work has been promoted via several channels (e.g. social media, public press, presentations) and is contributing to a report. AH reports that she is an unpaid member of two Data Monitoring and Safety Boards for National Health and Medical Research Council‐funded trials that are testing vaporised nicotine products in adults. She is an independent personnel on this board and has no connection to the study or funding, and is not compensated for this work, and the outcomes of this trial have no impact (positive or negative) on her. Her role is to act as an independent expert in public health to ensure that the studies are being conducted appropriately and safely. AH is also a Methods Editor for Cochrane Public Health, but has not been involved in the editorial process or assessment of this review.

CBi: no interests declared.

JM: no interests declared.

LW: declares that his institution has received research grants to undertake trials likely to be included in this review. LW also reports that he is the Co‐ordinating Editor of Cochrane Public Health, but has not been involved in the editorial process or assessment of this review.

Edited (no change to conclusions)