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Trial registered on ANZCTR


Registration number
ACTRN12623000079640
Ethics application status
Approved
Date submitted
18/12/2022
Date registered
25/01/2023
Date last updated
2/06/2024
Date data sharing statement initially provided
25/01/2023
Type of registration
Prospectively registered

Titles & IDs
Public title
Efficacy of a text-message based intervention in preventing adolescent e-cigarette use
Scientific title
A randomised controlled trial to examine the potential effect of a text-message based intervention on preventing adolescent e-cigarette use
Secondary ID [1] 308606 0
n/a
Universal Trial Number (UTN)
Trial acronym
Linked study record
This trial combines and replaces the following trials: ACTRN12622000901707p and ACTRN12622000905763p, both of which have been withdrawn and will no longer occur.

Health condition
Health condition(s) or problem(s) studied:
E-cigarette use 328496 0
Condition category
Condition code
Public Health 325523 325523 0 0
Health promotion/education
Mental Health 325524 325524 0 0
Addiction

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
A randomised controlled trial employing a 2x2 factorial design will be conducted to test the effectiveness of a theory-based intervention to prevent e-cigarette use among adolescents aged 12 to 15 years. Parent-adolescent dyads will be randomly allocated to one of the following four groups:

Adolescent text-messages (group one): Adolescents from the parent-adolescent dyads allocated to Group one will receive a theory-based intervention to prevent adolescent e-cigarette use lasting up to two years. The intervention messages will be drawn from a library of text messages targeting adolescent e-cigarette use developed following extensive consultation with parents and adolescents via focus groups, semi-structured interviews and online surveys, in addition to consultation with researchers and experts from the field of e-cigarettes and tobacco. The messages target domains within the Theory of Triadic Influence (i.e. adolescent self-efficacy and behavioural control; social normative beliefs; and attitudes towards the behaviour), a theory frequently employed to guide the development of text-message based interventions to prevent and address adolescent tobacco use (Flay et al 2009). 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. Messages will be 320 characters or less (size of 2 standard text messages), and may include links to websites or youtube videos. Other messages will be plain text only. Adolescents will receive one message per week for 9-10 weeks across a school term. Following this, adolescents will receive one booster message per term, resulting in 12 messages total per year.
Parents from the parent-adolescent dyads allocated to Group one 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 (group two): Parents from the parent-adolescent dyads allocated to Group two will receive a theory-based intervention to prevent adolescent e-cigarette use lasting up to two years. The intervention will consist of a library of text messages targeting parents developed following the extensive process outlined above in Group one. The messages target constructs within the Theory of Triadic Influence (i.e. adolescent self-efficacy and behavioural control; social normative beliefs; and attitudes towards the behaviour), a theory frequently employed to guide the development of text-message based interventions to prevent and address adolescent tobacco use (Flay et al 2009). 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. Messages will be 320 characters or less (size of 2 standard text messages), and may include links to websites or youtube videos. Other messages will be plain text only. Parents will receive one message per week for 9-10 weeks across a school term. Following this, parents will receive one booster message per term, resulting in 12 messages total per year.
Adolescents from the parent-adolescent dyads allocated to Group two will not receive the adolescent text-messages during the intervention period.

Parent and adolescent text-messages (group three): Parent-adolescent dyads randomly allocated to Group three will receive both the parent and adolescent text-messages described above. Parents and adolescents will receive the text-messages concurrently. Parents will also receive the e-cigarette factsheet.

Read receipts will be automatically captured via the text message program to monitor adherence. Both adolescents and parents will be asked to report on their receipt and reading of text messages at 6 month followup. We will also collect web analytics to determine how frequently a link in any text message is clicked. Adherence to reading the factsheet will not be monitored.
Intervention code [1] 325055 0
Prevention
Intervention code [2] 325056 0
Behaviour
Comparator / control treatment
Control (group four): Parents in the parent-adolescent dyads allocated to the control group will receive the e-cigarette factsheet described above. Adolescents will not receive anything. Distribution of the text-messages will be controlled centrally by the research team, limiting the potential for contamination between groups.

Adherence to reading the factsheet will not be monitored.
Control group
Active

Outcomes
Primary outcome [1] 333366 0
Adolescent susceptibility to e-cigarette use will be assessed in an online or telephone survey conducted by a trained research assistant at baseline, 6-, 12- and 24-month follow-up. Validated survey items outlined by Carey et al. will be used to assess adolescent susceptibility to use e-cigarettes. Adolescents will be asked to respond on a 4-point scale, ranging from 1 (definitely not) to 4 (definitely yes).
Timepoint [1] 333366 0
Baseline, 6-(primary endpoint), 12- and 24-month follow-up post-intervention commencement
Secondary outcome [1] 416759 0
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. To aid comparisons of the effect of e-cigarette policies and interventions, Pearson et al. recommends for eight core constructs of e-cigarette use to be assessed. As such, adolescents that report e-cigarette ever-use at follow-up will be asked additional survey items (recommended by Pearson et al.) to assess the remaining constructs, including: frequency of e-cigarette use; former daily use; relative perceived harm; device type; primary flavour preference; presence of nicotine within the e-cigarettes; and primary reason for use.
Timepoint [1] 416759 0
Baseline, 6-, 12- and 24-month follow-up post-intervention commencement
Secondary outcome [2] 416760 0
Adolescent tobacco-use will be assessed via an online or telephone survey conducted by a trained research assistant. As recommended by the World Health Organisation to measure youth tobacco use, survey items include ever-use of cigarettes (defined as lifetime use, including one or two 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).
Timepoint [2] 416760 0
Baseline, 6-, 12- and 24-month follow-up post-intervention commencement
Secondary outcome [3] 416761 0
Acceptability of the text-message intervention: Acceptability (defined as the perception amongst adolescents and parents that the intervention is agreeable, palatable or satisfactory) will be assessed in an online or telephone survey at 6 months follow-up with adolescents (i.e. Group one and group three) and parents (i.e. Group two and group three) who received the text-messages. Survey items to assess acceptability will be based on validated items developed by Weiner et al. (20) and those previously used by the research team. Parents and adolescents will be asked to respond on a 5-point Likert scale, ranging from 1 (strongly disagree) to 5 (strongly agree).
Timepoint [3] 416761 0
6-month follow-up post-intervention commencement
Secondary outcome [4] 416762 0
Attitudes to the behaviour: Changes in the three Theory of Triadic Influence domains targeted by the intervention (i.e. adolescent self-efficacy and behavioural control; social normative beliefs; and attitudes towards the behaviour) that may work to drive changes in the primary and secondary outcomes as a result of the intervention will be assessed via an online or telephone survey with adolescents. Validated survey items developed by Barker et al. and modified items from a validated survey by Zourbanos et al. have been mapped to the three Theory of Triadic Influence domains targeted by the intervention to determine how the intervention may influence e-cigarette intentions and behaviour. Adolescents will be asked to respond to each item on a 5-point scale, ranging from 1 (definitely would not) to 5 (definitely would).
Timepoint [4] 416762 0
Baseline, and 6-months follow-up post-intervention commencement
Secondary outcome [5] 416763 0
Parent knowledge, behaviour and skills relating to e-cigarettes: will be assessed via an online or telephone survey conducted by a trained research assistant at with parents in all groups. Survey items will capture information on e-cigarette use and accessibility in the home environment, as well as parent knowledge of e-cigarettes and perceived confidence to discuss and provide support to adolescents regarding e-cigarettes. Parents will be asked to respond to each item on a 5-point scale, ranging from 1 (strongly disagree) to 5 (strongly agree)
Timepoint [5] 416763 0
Baseline, 6-, 12- and 24-month follow-up post-intervention commencement
Secondary outcome [6] 417735 0
Adolescent self-efficacy and behavioral control: Changes in the Theory of Triadic Influence domains targeted by the intervention (i.e. adolescent self-efficacy and behavioural control; social normative beliefs; and attitudes towards the behaviour) that may work to drive changes in the primary and secondary outcomes as a result of the intervention will be assessed via an online or telephone survey with adolescents. Validated survey items developed by Barker et al. and modified items from a validated survey by Zourbanos et al. have been mapped to the three Theory of Triadic Influence domains targeted by the intervention to determine how the intervention may influence e-cigarette intentions and behaviour. Adolescents will be asked to respond to each item on a 6 point scale (Very sure I would vape to very sure I would not vape)
Timepoint [6] 417735 0
Baseline and 6 months follow-up post-intervention commencement
Secondary outcome [7] 417736 0
Social normative beliefs: Changes in the three Theory of Triadic Influence domains targeted by the intervention (i.e. adolescent self-efficacy and behavioural control; social normative beliefs; and attitudes towards the behaviour) that may work to drive changes in the primary and secondary outcomes as a result of the intervention will be assessed via an online or telephone survey with adolescents. Validated survey items developed by Barker et al. and modified items from a validated survey by Zourbanos et al. have been mapped to the three Theory of Triadic Influence domains targeted by the intervention to determine how the intervention may influence e-cigarette intentions and behaviour. Adolescents will be asked to respond to each item on a 5-point scale, ranging from 1 (definitely would not) to 5 (definitely would).
Timepoint [7] 417736 0
Baseline and 6 months follow-up post-intervention commencement

Eligibility
Key inclusion criteria
Parent-adolescent dyads, consisting of adolescents aged between 12 to 15 years, located within Australia will be recruited. To be eligible: (1) parents and adolescents must have sufficient English to engage with the intervention; and (2) adolescents must own or have exclusive access to a mobile phone. For the purpose of this research, ‘parents’ will be defined as a parent or legal guardian that has the authority to consent to the participation of a minor in a human research project, and will be hereafter referred to as ‘parents’ within this protocol and supporting documents.
Minimum age
12 Years
Maximum age
99 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
None

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation will be concealed through central randomisation occuring via computer, following baseline data collection.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Following baseline data collection, an independent statistician will randomise parent-adolescent dyads, using a computerised random number function in Microsoft Excel, stratified by the geographic and socio-economic location in a 1:1:1:1 ratio to one of the four trial groups (described below). Dyads are unable to change groups following randomisation and allocation.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Factorial
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Statistical analyses will be conducted using STATA v14. Descriptive statistics, including proportions, means and standard deviations, will be used to describe adolescent and parent characteristics, and acceptability of the text-message intervention.

Analyses of trial outcomes will be undertaken under an intention to treat (ITT) framework, with all adolescents with baseline data to be included in the analysis. For the primary analyses, which will include never-users of e-cigarettes at baseline, to assess the effects of the parent and adolescent text-message interventions separately, mixed effects regression models will be used to assess between group differences in interventions (adolescent text-messages vs no adolescent text-messages; and parent text-messages vs no parent messages) in adolescent outcomes at follow-up. For the dichotomised outcomes (i.e. adolescent susceptibility to e-cigarette use), a generalized linear mixed model will be used. Each model will include a fixed effect for each experimental group. For the secondary analyses, the synergistic effects between the two interventions will be explored by including a parent by adolescent interaction term in all models. We will examine the potential interaction between interventions graphically by displaying outcome measures by group.

We will employ multiple imputation following ITT principles for any missing data in the event that participants withdraw from the study and request that their data is not used. If for any reason participants do not receive the intervention they are assigned to (I.e. contamination occurs), they will be excluded from analysis. All statistical tests will be 2 tailed with alpha of 0.05.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
27/02/2023
Actual
27/02/2023
Date of last participant enrolment
Anticipated
31/12/2024
Actual
Date of last data collection
Anticipated
30/04/2025
Actual
Sample size
Target
255
Accrual to date
120
Final
Recruitment in Australia
Recruitment state(s)
ACT,NSW,NT,QLD,SA,TAS,WA,VIC

Funding & Sponsors
Funding source category [1] 312851 0
Charities/Societies/Foundations
Name [1] 312851 0
Hunter Medical Research Foundation
Country [1] 312851 0
Australia
Primary sponsor type
University
Name
University of Newcastle
Address
University Drive
Callaghan NSW 2308

Country
Australia
Secondary sponsor category [1] 314500 0
Government body
Name [1] 314500 0
Hunter New England Population Health
Address [1] 314500 0
Locked Bag 10
Wallsend NSW 2287
Country [1] 314500 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 312128 0
University of Newcastle HREC
Ethics committee address [1] 312128 0
Ethics committee country [1] 312128 0
Australia
Date submitted for ethics approval [1] 312128 0
12/08/2022
Approval date [1] 312128 0
16/12/2022
Ethics approval number [1] 312128 0
H-2022-0340

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 123578 0
Prof Luke Wolfenden
Address 123578 0
Hunter New England Population Health
Locked Bag 10
Wallsend, NSW 2287
Country 123578 0
Australia
Phone 123578 0
+61 2 4924 6567
Fax 123578 0
Email 123578 0
Luke.Wolfenden@health.nsw.gov.au
Contact person for public queries
Name 123579 0
Courtney Barnes
Address 123579 0
Hunter New England Population Health
Locked Bag 10
Wallsend, NSW 2287
Country 123579 0
Australia
Phone 123579 0
+61249246678
Fax 123579 0
Email 123579 0
Courtney.Barnes@health.nsw.gov.au
Contact person for scientific queries
Name 123580 0
Courtney Barnes
Address 123580 0
Hunter New England Population Health
Locked Bag 10
Wallsend, NSW 2287
Country 123580 0
Australia
Phone 123580 0
+61249246678
Fax 123580 0
Email 123580 0
Courtney.Barnes@health.nsw.gov.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
No individual participant data for this trial will be available as ethics approval does not cover this. If a request for individual participant data is made and appropriate ethics approvals obtained, such data may be made available in the future.


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.