ABSTRACT

Introduction Adolescent e-cigarette use, globally and within Australia, has increased in recent years. In response, public health agencies have called for the development of education and communication programmes targeting adolescents. Despite such recommendations, few rigorous evaluations of such interventions currently exist. The main objective of this study is to examine the potential effect of a text-message intervention targeting parents and adolescents on adolescent susceptibility to e-cigarette use (e.g. intentions towards using e-cigarettes). Secondary objectives are to: (1) examine the effect of the intervention on adolescent e-cigarette and combustible tobacco use; and (2) examine the acceptability of the intervention.

Methods and analysis A randomised controlled trial employing a 2x2 factorial design will be conducted with parent-adolescent dyads (aged 12-15 years). Dyads will be randomly allocated to one of four arms: Arm 1 - a text-message intervention delivered to adolescents only; Arm 2 – a text- message intervention delivered to the parents of adolescents only; Arm 3 – a text-message intervention delivered to both the parents and adolescents; and Arm 4 - an information only control, consisting of an e-cigarette factsheet provided to parents only. Participant recruitment commenced in April 2023 with the aim to recruit 120 parent-adolescent dyads. Data collection to assess study outcomes will occur at baseline, 6-, 12- and 24-months post the commencement of the intervention. The primary endpoint will be 6-month follow-up. The primary outcome will be adolescent susceptibility to e-cigarette use, assessed using validated items. Analyses of trial outcomes will be undertaken under an intention-to-treat framework, with all participants included in the analysis in the group they were allocated.

Ethics and dissemination Ethics approval has been obtained from the University of Newcastle Human Research Ethics Committee (H-2022-0340). Findings will be disseminated in peer-reviewed journals and at conferences.

Trial registration Prospectively registered with Australia New Zealand Clinical Trials Registry (ACTRN12623000079640).

STRENGTHS AND LIMITATIONS

This study will employ a rigorous factorial randomised controlled trial design to test the effectiveness of a text-message based intervention;

This study will contribute to the limited existing evidence base, with no randomised controlled trials aiming to prevent adolescent e-cigarette use currently published yet several underway;

Selection bias may occur if adolescents who are highly susceptible to e-cigarette use refuse to participate in the study.

Competing Interest Statement

The authors have declared no competing interest.

Clinical Trial

Prospectively registered with Australia New Zealand Clinical Trials Registry (ACTRN12623000079640)

Funding Statement

This project is supported by a Hunter Medical Research Institute (HMRI) Early Career Project Grant and University of Newcastle School of Medicine and Public Health Project Grant and the NHMRC Centre for Research Excellence (No. APP1153479), the National Centre of Implementation Science. The funders have played no role in the conduct of the trial. Hunter New England Local Health District, Population Health and the University of Newcastle provided infrastructure and in kind funding. Courtney Barnes receives salary support from a NSW Ministry of Health PRSP Research Fellowship. Luke Wolfenden receives salary support from an NHMRC Investigator (L1) Fellowship (APP11960419) and NSW Cardiovascular Research Capacity Program grant number H20/28248. David Meharg receives a salary for his employment at the University of Sydney through a NHMRC, Australia and Global Alliance for Chronic Diseases grant (NHMRC GACD 1116081) and is supported as a fellow of the Wingara Mura Leadership Program, University of Sydney and received a grant from The University of Sydney, Charles Perkins Centre Aboriginal and Torres Strait Islander Wingara Mura Leadership Academy Early to Mid Career Research Seeding Grant. Rebecca Kate Hodder receives salary support from a NHMRC Early Career Fellowship (APP1160419). The contents of this manuscript are the responsibility of authors and do not reflect the views of NSW Ministry of Health or NHMRC.

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethical approval has been provided by the University of Newcastle Human Research Ethics Committee (approval H 2022 0340).

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

Data Availability

No data is reported within the manuscript.

LIST OF ABBREVIATIONSEOIExpression of interest;EVALIe-cigarette or vaping product use associated lung injury;ITTIntention to treat;CONSORTConsolidated Standards of Reporting Trials;RCTRandomised controlled trial;SEIFASocio-Economic Indexes for Areas (SEIFA);SPIRITStatement and Standard ProtocolItemsRecommendations for Interventional Trials.