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Trial registered on ANZCTR


Registration number
ACTRN12622000581763
Ethics application status
Approved
Date submitted
6/04/2022
Date registered
20/04/2022
Date last updated
21/04/2023
Date data sharing statement initially provided
20/04/2022
Type of registration
Prospectively registered

Titles & IDs
Public title
Effects of tobacco health warnings and television advertisements to counter reassurance-based tobacco marketing among Australian smokers
Scientific title
Effects of systematically developed tobacco health warnings and television advertisements to counter reassurance-based tobacco marketing among Australian smokers: randomised controlled trial
Secondary ID [1] 306783 0
NHMRC#1142981
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Tobacco-related harm 325825 0
Condition category
Condition code
Public Health 323149 323149 0 0
Health promotion/education

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The study intervention involves exposing participants online to health warnings on tobacco packages. Participants will be randomly assigned to one of four conditions: (A) No Tobacco Health Warnings (control) consisting of exposure to warnings on over-the-counter medicines; (B) New Standard Health Warnings (control) to represent the usual situation; (C) Product Attribute Health Warnings; or (D) Product Attribute Health Warnings plus a TV advertisement.

The online study will be accessed individually by participants (via a web link in an email invitation or the panel's online dashboard) at a time and location of their convenience. After completing baseline survey questions, participants will be exposed to the warning label intervention in the form of images of seven warnings on tailor-made cigarette packs or roll-your-own tobacco pouches. Participants will be shown, in order (i) an image of the front of the product; (ii) an image of the back of the product; (iii) an image of the side of the product (for tailor-made cigarette packs) or under the flap (for roll-your-own pouches); and (iv) an image of the full health warning (all three components together). These four images will be displayed on four consecutive screen displays. Each image will be displayed for a minimum of ten seconds and a maximum of two minutes. Participants will click on a ‘Next’ button when they are ready to move to the next image, and they will not be able to proceed without viewing each image. Participants will complete a single rating of each warning immediately after viewing it. After this section is complete, participants randomised to the Product Attribute Health Warnings plus TV advertisement condition will also view a 30 second TV advertisement twice; these participants will not be able to proceed until after the TV advertisement has finished playing. They will then complete ratings of the TV advertisement.

Following the baseline survey and initial intervention exposure, for seven consecutive days consenting participants will be emailed a weblink which will take them to a single image of a warning containing all 3 warning components together that they were exposed to at baseline. (i.e., repeated exposure). After viewing the image, participants will be asked one or two simple questions (e.g. they will be asked to rate how believable or relevant they think the warning is). Participants randomised to the Product Attribute Health Warnings plus TV ad condition will also view a 15 second TV advertisement on days two and day four of the repeated warning exposure. Data collection will capture whether participants clicked on the weblink, and which image and TV advertisement they were served on each day of repeated exposure. Participants will then be invited to complete two follow-up surveys, one which will be sent eight days after completion of the initial exposure session, and another which will be sent approximately four weeks after completion of the initial exposure session. During the follow-up surveys, participants will be asked about their cigarette consumption, sensory experiences of different tobacco products, and quitting behaviours and intentions over the past week.

The content and format of the intervention warning stimuli were systematically developed and professionally designed for the study. The content of the TV advertisement was professionally produced for the study.
Intervention code [1] 323239 0
Behaviour
Intervention code [2] 323240 0
Lifestyle
Intervention code [3] 323241 0
Prevention
Comparator / control treatment
There are two comparator/control groups for this study.
Participants randomised to the (A) No Tobacco Health Warnings (control) condition will be exposed to health warnings on common over-the-counter medicines, while participants randomised to the (B) New Standard Health Warnings (control) condition will be exposed to tobacco warnings on tailor-made cigarette packs or roll-your-own tobacco pouches (depending on what they report smoking more of) that are representative of an updated set of the current set of health warnings (i.e. similar to what participants are used to seeing on their tailor-made cigarette packs or roll-your-own-tobacco pouches). Both control treatments will be provided using the same mode and frequency as the intervention treatments - with the exception of the TV advertisement, which is exclusive to the participants randomised to the Product Attribute and TV advertisement condition.

The 'No tobacco health warning' stimuli of common over-the-counter medicines were sourced from the website of a major pharmacy chain.

The content for Standard Health Warnings were developed by a team of researchers in the Centre for Behavioural Research in Cancer, under a program of work contracted in 2020 by the Australian Government Department of Health.
Control group
Active

Outcomes
Primary outcome [1] 330916 0
Enjoyment when smoking measured by assessing:
1) enjoyment of 10 smoking related sensory experiences using a 100-point Visual Analogue Scale (VAS).
2) if inhaling smoke from cigarettes in the past week was less enjoyable than before, using a 5-point Likert scale.
Timepoint [1] 330916 0
Component 1 is measured at baseline (immediately pre-intervention), and at 8 days (primary timepoint) and 4 weeks (exploratory timepoint) after intervention commencement.
Component 2 is measured 8 days after intervention commencement (primary timepoint).
Primary outcome [2] 330917 0
Concern when smoking measured by assessing:
1) concern associated with 10 smoking related sensory experiences using a 100-point Visual Analogue Scale (VAS).
2) if participants thought about harms caused by smoking more than usual, using a 5-point Likert scale.
Timepoint [2] 330917 0
Component 1 is measured at baseline (pre-intervention), and at 8 days (primary timepoint) and 4 weeks (exploratory timepoint) after intervention commencement.
Component 2 is measured 8 days after intervention commencement (primary timepoint).
Primary outcome [3] 330920 0
Smoke limiting behaviours assessed using three items (e.g. limiting number of cigarettes, stubbing out a cigarette before finishing and forgoing cigarettes) measured on a 5-point scale.
Timepoint [3] 330920 0
8 days (primary timepoint) and 4 weeks (exploratory timepoint) after intervention commencement.
Secondary outcome [1] 408062 0
Reflection on own tobacco product assessed using two items; 1) on the feel and taste of smoke and 2) what is in the smoke. Answer options are 'Yes', 'No', and 'Don't Know/Can't Say'.
Timepoint [1] 408062 0
Approximately 3 days after the intervention commencement (at the third repeated exposure task).
Secondary outcome [2] 408098 0
Feelings of discord or discomfort (e.g. put off, uneasy) when smoking assessed using three items measured on a 5-point Likert scale.
Timepoint [2] 408098 0
8 days after intervention commencement.
Secondary outcome [3] 408101 0
Negative emotional responses to warnings (e.g. feeling uncomfortable or embarrassed) assessed using five items measured on a 5-point Likert scale.
Timepoint [3] 408101 0
Baseline (immediately post-intervention) and at 8 days after intervention commencement.
Secondary outcome [4] 408104 0
Knowledge gain assessed by using (1) 6 items for product attribute meta-message knowledge (e.g. level of agreement with the statement 'No matter how it feels, all cigarette smoke is just as damaging') measured on a 5-point Likert scale and (2) 12 items for health effects knowledge (e.g. whether participants think smoking causes lung cancer or a heart attack) with answer options 'yes', 'no' and 'don't know/can't say'.
Timepoint [4] 408104 0
Component 1 is measured at baseline (immediately post-intervention) and 8 days after intervention commencement.
Component 2 is measured 8 days after intervention commencement.
Secondary outcome [5] 408105 0
Ongoing engagement with the intervention warnings and television advertisement assessed using: two items on rumination (e.g. how often the messages/images from the warnings came back into their mind, measured on a 5-point Likert scale), one item on information seeking behaviour (with yes/no response options) and one item on discussing the warnings with others (with yes/no response options).
Timepoint [5] 408105 0
8 days after intervention commencement.
Secondary outcome [6] 408107 0
Product misperceptions assessed using three items on the perceived harmfulness of different tobacco products (e.g. do participants think menthol cigarettes are more or less harmful than non-menthol cigarettes), measured on 5-point Likert scales.
Timepoint [6] 408107 0
4 weeks after intervention commencement (this is an exploratory outcome only given expected drop-out between intervention commencement and 4-week follow-up. The study was not powered to detect differences at 4-week follow-up).
Secondary outcome [7] 408108 0
Behaviour change assessed by measuring: i) tobacco product frequency and use for each of tailor-made cigarettes, roll-your-own tobacco and menthol cigarettes; ii) vaping frequency and use; and iii) number and length of quit attempts and quit-related help-seeking behaviours.
Timepoint [7] 408108 0
Change from baseline (immediately pre-intervention) to 8 days and 4 weeks after intervention commencement.
Secondary outcome [8] 408109 0
Quitting thoughts and intentions to change behaviour assessed using four items measuring 1) how often in the past week they have thought about quitting; 2) how often they have thought about the health risks of smoking; 3) how likely it is that they will try and quit smoking in the next month; and 4) how likely is it they will reduce the number of cigarettes they smoke per day or per week in the next month, Each item is measured on a 5-point Likert scale.
Timepoint [8] 408109 0
Components 1 and 2 are measured at 8 days and 4 weeks after intervention commencement.
Components 3 and 4 are measured at 4 weeks after intervention commencement.

Eligibility
Key inclusion criteria
Australian adults aged 18-69 years
At least weekly smokers of tailor-made cigarettes or roll-your-own tobacco
Provide informed consent.
Minimum age
18 Years
Maximum age
69 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Demographic quotas based on age and sex will be used. Quotas will also be applied to tobacco product type (e.g. tailor-made cigarettes, roll-your-own tobacco and menthol cigarettes) smoked at least weekly.
Participants will be excluded if the quota bracket they belong in has been filled.

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 is concealed. At the commencement of the baseline survey, following confirmation of participants' study eligibility, participants will be randomised to one of four warning conditions using a least-filled quota pre-programmed procedure.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Participants will be randomly assigned to condition using a dynamic (adaptive) random allocation method called quota least-fill randomisation. For each condition we have set quotas for three types of smokers based on the tobacco product types they smoke at least weekly: 1) menthol tailor-made cigarettes/menthol roll-your-own tobacco, 2) predominantly roll-your-own tobacco and 3) predominantly tailor-made cigarettes.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
We hypothesise exposure to the systematically developed Product Attribute Health Warning labels and Television advertisement will be associated with (i) decreased enjoyment when inhaling smoke with favourable sensory experiences; (ii) increased concern when inhaling smoke with favourable sensory experiences; and (iii) greater smoke-limiting behaviours in the week following intervention commencement (at 8 days after intervention commencement). To detect similar magnitudes of difference to what was observed when measuring smoke limiting behaviours such as forgoing of cigarettes in Thrasher et al. (2016) after exposure to graphic health warnings and in Vittiglia et al. (unpublished data) after exposure to a motivational anti-smoking campaign, at 90% power, two-tailed, p<.05 we require n=383 per group at 8-day follow-up. We estimate that 8% of participants will decline participation in any future phases of the project after completion of the Initial Exposure Session, and that an additional 34.6% of participants will drop out between the Initial Exposure Session and the 8-Day Follow-Up. Therefore, to ensure n=383 per group at 8-day follow-up, we need to recruit N=2,552 for the Initial Exposure Session (n=638 per condition; assuming 8% decline to participate in further phases of the project and an additional 34.6% drop out between the Initial Exposure Session and the 8-Day Follow-Up, N=1,535 will be retained at 8-Day Follow-Up (n=384 per condition)).

Preliminary analyses will assess if the distribution of the baseline demographic, past year quit attempts and future quitting intention variables vary across conditions. Binary primary and secondary outcomes will be analysed using logistic regression, while continuous primary and secondary outcomes will be analysed using linear regression.
We will estimate one model for each outcome. In this model, the No Tobacco Health Warning control condition will be the referent condition against which each other condition will be compared; we will obtain an effect size for how each condition compares to this control condition. To assess the effectiveness of the Product Attribute Health Warnings and Product Attribute Health Warnings plus TV ad, scores in each of these conditions will each be compared to that in the No Tobacco Health Warning control condition. To examine how Product Attribute Health Warnings compare to New Standard Health Warnings, responses from participants in the Product Attribute Health Warnings condition and in the Product Attribute Health Warnings + TV Ad condition will each be compared to those in the control condition (i.e., Effect Sizes A and B) and responses from participants in the New Standard Health Warnings condition will also be compared to those in the control condition (i.e., Effect Size C). The effect size from each comparison will be compared to determine if there is a difference in effectiveness of PAHWs and SHWs (i.e., Effect Size A vs. Effect Size C; Effect Size B vs. Effect Size C). To examine whether exposure to the complementary TV Ad increases effects of the Product Attribute Health Warnings, responses from participants in the Product Attribute Health Warning condition will be compared to those in the control condition (i.e., Effect Size A) and responses from participants in the Product Attribute Health Warning + TV Ad condition will also be compared to those in the control condition (i.e., Effect Size B). The effect size from each comparison will be used to determine if there is a difference in effectiveness when PAHWs are accompanied by a complementary TV Ad (i.e., Effect Size A vs. Effect Size B). The model will include the full sample. A p-value of 0.01 or less will be deemed to indicate a significant finding due to the large number of comparisons.

References
James F. Thrasher, Kamala Swayampakala, Ron Borland, Gera Nagelhout, Hua-Hie Yong, David Hammond, Maansi Bansal-Travers, Mary Thompson & James Hardin (2016) Influences of Self-Efficacy, Response Efficacy, and Reactance on Responses to Cigarette Health Warnings: A Longitudinal Study of Adult Smokers in Australia and Canada, Health Communication, 31:12, 1517-1526, DOI: 10.1080/10410236.2015.1089456

Vittiglia A, Mitsopoulos E, and Durkin S. Evaluation of the Sticky Blood campaign (2021): Findings from the VSMTS (Wave 1). Melbourne, Australia: Centre for Behavioural Research in Cancer, Cancer Council Victoria, 2021.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
30/05/2022
Actual
3/08/2022
Date of last participant enrolment
Anticipated
22/07/2022
Actual
15/09/2022
Date of last data collection
Anticipated
26/08/2022
Actual
1/11/2022
Sample size
Target
2552
Accrual to date
Final
2591
Recruitment in Australia
Recruitment state(s)
ACT,NSW,NT,QLD,SA,TAS,WA,VIC

Funding & Sponsors
Funding source category [1] 311120 0
Government body
Name [1] 311120 0
National Health and Medical Research Council (NHMRC)
Country [1] 311120 0
Australia
Primary sponsor type
Individual
Name
Professor Melanie Wakefield
Address
Centre for Behavioural Research in Cancer
Cancer Council Victoria
615 St Kilda Road
Melbourne VIC 3004
Country
Australia
Secondary sponsor category [1] 312456 0
None
Name [1] 312456 0
Address [1] 312456 0
Country [1] 312456 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 310650 0
Cancer Council Victoria Institutional Research Review Committee
Ethics committee address [1] 310650 0
Ethics committee country [1] 310650 0
Australia
Date submitted for ethics approval [1] 310650 0
10/03/2022
Approval date [1] 310650 0
30/03/2022
Ethics approval number [1] 310650 0
IER 1706

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

Contacts
Principal investigator
Name 118394 0
Prof Melanie Wakefield
Address 118394 0
Centre for Behavioural Research in Cancer
Cancer Council Victoria
615 St Kilda Road
Melbourne VIC 3004
Country 118394 0
Australia
Phone 118394 0
+61 3 9514 3651
Fax 118394 0
Email 118394 0
melanie.wakefield@cancervic.org.au
Contact person for public queries
Name 118395 0
Emily Brennan
Address 118395 0
Centre for Behavioural Research in Cancer
Cancer Council Victoria
615 St Kilda Road
Melbourne VIC 3004
Country 118395 0
Australia
Phone 118395 0
+61 3 9514 6355
Fax 118395 0
Email 118395 0
Emily.Brennan@cancervic.org.au
Contact person for scientific queries
Name 118396 0
Emily Brennan
Address 118396 0
Centre for Behavioural Research in Cancer
Cancer Council Victoria
615 St Kilda Road
Melbourne VIC 3004
Country 118396 0
Australia
Phone 118396 0
+61 3 9514 6355
Fax 118396 0
Email 118396 0
Emily.Brennan@cancervic.org.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 will not be available. Output will be disseminated in peer reviewed publications by the research team.


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.