Trial Review

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Trial registered on ANZCTR


Registration number
Ethics application status
Yes
Date submitted
21/10/2013
Date registered
Date last updated

Titles & IDs
Public title
Weight loss using Implementation Intentions and Mental Imagery.
Scientific title
Weight loss using Implementation Intentions and Mental Imagery: A randomized controlled intervention
Secondary ID [1] 282574 0
Nil known
Universal Trial Number (UTN)
U1111-1143-5633
Trial acronym
WIIM trial
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obesity 289254 0
Condition category
Condition code
Diet and Nutrition 289576 289576 0 0
Obesity

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
12 week intervention using the strategies of implementation intentions and mental imagery to assist with behaviour change in the area of diet and physical activity. The use of text messages to augment the intervention effectiveness will also be explored.

Behavioural, psychological, and biomedical outcomes and measures will occur at baseline and at various time periods to monitor behaviour change.

Three conditions.
1. Psycho-education Control
2. Implementation intentions and mental imagery.
3. Implementation intentions and mental imagery with text messages.
Intervention code [1] 287235 0
Lifestyle
Intervention code [2] 287236 0
Behaviour
Comparator / control treatment
Active control - standard treatment. Psycho-education on diet and physical activity guidelines to assist with weight loss.
Control group
Active

Outcomes
Primary outcome [1] 289671 0
Biomedical: Body weight (kg), Body fat percentage, Skeletal muscle percentage, viseral fat level, resting metabolic rate, body mass index, waist-hip ratio.
Timepoint [1] 289671 0
Week 6 and 12.
Primary outcome [2] 289672 0
Psychological: Risk perception, intention, planning, motivation, self efficacy, goal setting, outcome expectancies.
Timepoint [2] 289672 0
Baseline compared to week 6.
Secondary outcome [1] 302982 0
Biomedical: bone mass, muscle mass. Blood lipoproteins (LDL, HDL, total cholesterol, TG) glucose, insulin.
Timepoint [1] 302982 0
Week 6 and 12.
Secondary outcome [2] 303213 0
Psychological: Quality of life, and depression, anxiety, stress symptoms.

Biomedical: systolic blood pressure and diastolic blood pressure.

Behavioural: Physical activity behaviour, Diet habits behaviour.
Timepoint [2] 303213 0
Week 6 and 12.

Eligibility
Key inclusion criteria
Community Sample of obese and overweight individuals
(BMI between 25 and 40).
Minimum age
18 Years
Maximum age
65 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Serious health conditions.
Inability to engage in any form of physical activity.
Pregnancy.
Depression.
Not willing to engage in blood samples and body composition scans.
No access to mobile phone with text message features.
Inability to commit to follow up clinic sessions

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Participants will be randomly allocated to one of three group conditions using a computer-generated schedule. Based on identification numbers participants will be assigned to their number condition (1, 2, or 3). Each participant will also be provided with a participant identified number. Each participant identification numbers will be assigned to watch one of two versions of a video presentation, which contains the intervention manipulations. The researcher will be unaware of which video presentation corresponds to which treatment condition.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computer generated schedule.
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
A series of 3 x 2 MANCOVAs with repeated measures on the time variable will be used to analyse the study data. Baseline measures will be covariates in the model. 3 x 2 MANCOVAs will be conducted for each set of outcome variables (biomedical, behavioural, psychological).

Pending significant multivariate effects, follow-up univariate ANCOVAs will be used to identify differences for individual variables within each outcome set.

Sample size is determined by a power analysis using the G*Power 3.1 Program, suitable to evaluate differences between the three condition levels greater than 10%, with statistical power > 0.80 and at < 0.05 probability level (Faul, Erdfelder, Buchner, & Lang 2009). Based on Andersson and Moss’ (2011) study that explored an intervention using imagery and implementation intentions, to increase exercise behaviour and found a large effect size, we anticipate a large effects size in the current study. Given the estimated effect size, the required sample size in each condition, with 80% power is 22 (thus 66 in total). To account for a 35% drop out rate and eliminations of cases due to missing data or spoilt questionnaires (Hagger et al., 2012), this study aims to acquire 34 participants per condition (total 102).

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
6/01/2014
Actual
Date of last participant enrolment
Anticipated
12/01/2015
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
102
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
WA
Recruitment postcode(s) [1] 6920 0
6102 - Bentley
Recruitment postcode(s) [2] 6921 0
6982 - Bentley

Funding & Sponsors
Funding source category [1] 287354 0
University
Name [1] 287354 0
Curtin University of Technology, Bentley.
Country [1] 287354 0
Australia
Primary sponsor type
University
Name
Curtin University of Technology
Address
Postal Address:
Curtin University of Technology
GPO Box U1987 Perth,
Western Australia 6845
Country
Australia
Secondary sponsor category [1] 286101 0
None
Name [1] 286101 0
Address [1] 286101 0
Country [1] 286101 0
Other collaborator category [1] 277435 0
University
Name [1] 277435 0
Dr Martin Hagger
Address [1] 277435 0
School of Psychology

Curtin University of Technology, Bentley

GPO Box U1987 Perth,
Western Australia 6845
Country [1] 277435 0
Australia
Other collaborator category [2] 277436 0
University
Name [2] 277436 0
Associate Professor Sebely Pal
Address [2] 277436 0
School of Public Health

Curtin University of Technology, Bentley

GPO Box U1987 Perth,
Western Australia 6845
Country [2] 277436 0
Australia

Ethics approval
Ethics application status
Yes
Ethics committee name [1] 289329 0
Human Research Ethics
Ethics committee address [1] 289329 0
Curtin University of Technology
The Secretary, HREC
Office of Research and Development
PO Box U1987
Perth WA 6845
Ph: +61 8 9266 9223
hrec@curtin.edu.au
Ethics committee country [1] 289329 0
Australia
Date submitted for ethics approval [1] 289329 0
03/09/2013
Approval date [1] 289329 0
16/09/2013
Ethics approval number [1] 289329 0
HR137/2013
Ethics committee name [2] 289330 0
Ethics committee address [2] 289330 0
Ethics committee country [2] 289330 0
Date submitted for ethics approval [2] 289330 0
Approval date [2] 289330 0
Ethics approval number [2] 289330 0

Summary
Brief summary
The current research will investigate the efficacy of a brief, minimal contact, cost effective theory-based intervention using implementation intentions and mental imagery techniques to target diet and physical activity behaviour to promote weight loss. In addition, the present study will evaluate whether mobile phone text messaging will be effective in augmenting the effectiveness of the intervention.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 40330 0
Ms Anne Hattar
Address 40330 0
Anne Hattar / Martin Hagger

Curtin University of Technology
School of Psychology
GPO Box U1987
Perth Western Australia 6845
Country 40330 0
Australia
Phone 40330 0
+61 456 103 197
Fax 40330 0
Email 40330 0
weightloss@curtin.edu.au
Contact person for public queries
Name 40331 0
Ms Anne Hattar
Address 40331 0
Anne Hattar / Martin Hagger

Curtin University of Technology
School of Psychology
GPO Box U1987
Perth Western Australia 6845
Country 40331 0
Australia
Phone 40331 0
+61 498 093 324
Fax 40331 0
Email 40331 0
weightloss@curtin.edu.au
Contact person for scientific queries
Name 40332 0
Prof Martin Hagger and Sebely Pal
Address 40332 0
Curtin University of Technology
School of Psychology
GPO Box U1987
Perth Western Australia 6845
Country 40332 0
Australia
Phone 40332 0
+61 08 92662215
Fax 40332 0
Email 40332 0
Martin.hagger@curtin.edu.au; s.pal@curtin.edu.au

No information has been provided regarding IPD availability


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.