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Trial registered on ANZCTR


Trial ID
ACTRN12613001274763
Ethics application status
Approved
Date submitted
21/10/2013
Date registered
19/11/2013
Date last updated
19/11/2013
Type of registration
Prospectively registered

Titles & IDs
Public title
Weight loss using Implementation Intentions and Mental Imagery.
Scientific title
The effect of Implementation Intentions and Mental Imagery on weight loss in a community sample of obese and overweight individuals: 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.

Following baseline measures, all participants will be required to watch a one hour weight loss video program. This video will contain the intervention manipulations.

Two versions of the program will exist.

Version 1, provided to control participants, will include general information including study details, and psycho-education regarding the diet and physical activity guidelines as per the weight loss intervention (consume recommended daily calorie intake; and participate in 30 minutes of daily exercise). Participants will also receive further information during the video presentation such as: the definition of a calorie, how to calorie count, which exercises are more intensive, tools to assist them with monitoring their physical activity and calorie intake (e.g., a provided calorie counting book), and how to record consumed calories and physical activity via a provided food and exercise log book. Participants will be asked to list some goals to help them met the diet and physical activity guidelines.

Version 2, will be provided to participants in the two conditions with the mental imagery and implementation intentions components. Version 2 will include the exact information from version 1; however will also include instructions for goal setting, mental imagery and implementation intentions techniques. Specifically, participants will be provided with instructions to guide them to mentally imagine the steps needed to reach their goals. Participants are then asked to create implementation intentions plans using an If/then format. Participants viewing the Version 2 video intervention will be directed to record their Goals, If/then plans, and mental imagery steps to provide to the researcher.

Participants within the implementation intention and mental imagery with text messages condition (condition 3), will receive weekly text message reminders during the 12 week intervention period. One text message per week will be sent to the participants mobile with a total of 11 text messages. The texts will contain goal reminders that relate to the participants diet and physical activity goals, implementation intentions and mental imagery. For example: “Hello, I would like to ask you to take the time to remember your goals and the steps you need to take to reach them. Remember when you visualised these steps for your diet and exercise goals when watching the video?"
Intervention code [1] 287235 0
Lifestyle
Intervention code [2] 287236 0
Behaviour
Comparator / control treatment
Active control. Psycho-education on diet and physical activity guidelines to assist with weight loss.
Control group
Active

Outcomes
Primary outcome [1] 289671 0
Biomedical outcomes: Body weight (kg).

Measured using a digital body composition monitor scale
Timepoint [1] 289671 0
Baseline, week 6 and 12.
Primary outcome [2] 290764 0
Biomedical: Body fat percentage.

Measured using a total body scanner named Dual-energy X-ray absorptiometry (DEXA).
Timepoint [2] 290764 0
Baseline, week 6 and 12.
Secondary outcome [1] 302982 0
Biomedical: bone mass.

Measured using a total body scanner named Dual-energy X-ray absorptiometry (DEXA).
Timepoint [1] 302982 0
Baseline, week 6 and 12.
Secondary outcome [2] 303213 0
Psychological: Quality of life

Measured using the The Impact of Weight on Quality of Life Questionnaire (IWQOL - Lite).
Timepoint [2] 303213 0
Baseline, week 6 and 12.
Secondary outcome [3] 305222 0
Psychological: Risk perception.

Measured using items adapted from Barg and colleagues (2012) study questionnaire.
Timepoint [3] 305222 0
Baseline, post-intervention, week 6 and 12.
Secondary outcome [4] 305223 0
Psychological: intention.

Measured using items adapted from Barg and colleagues (2012) study questionnaire.
Timepoint [4] 305223 0
Baseline, post-intervention, week 6 and 12.
Secondary outcome [5] 305224 0
Psychological: motivation.


Measured using items adapted from Hagger and colleagues (2012) study questionnaire.
Timepoint [5] 305224 0
Baseline, post-intervention, Week 6 and 12.
Secondary outcome [6] 305225 0
Psychological: planning.

Measured using an items adapted from Barg and colleagues (2012) study questionnaire.
Timepoint [6] 305225 0
Baseline, post-intervention, Week 6 and 12.
Secondary outcome [7] 305226 0
Psychological: self efficacy.

Measured using items adapted from Barg and colleagues (2012) study questionnaire.
Timepoint [7] 305226 0
Baseline, post-intervention, week 6 and 12.
Secondary outcome [8] 305227 0
Psychological: goal setting.

Items will be developed for the current study. Six open ended questions will be used. The answers to these items will be "coded" appropriately based on whether they are appropriate and realistic.
Timepoint [8] 305227 0
Baseline, post-intervention, week 6 and 12.
Secondary outcome [9] 305228 0
Psychological: outcome expectancies.

Measured using an items adapted from Barg and colleagues (2012) study questionnaire.
Timepoint [9] 305228 0
Baseline, post-intervention, week 6 and 12.
Secondary outcome [10] 305229 0
Psychological: Depression, anxiety, stress symptoms.

Measured using the Depression Anxiety Stress Scale (DASS -21) by Lovibond and Lovibond (1995).
Timepoint [10] 305229 0
Baseline, week 6 and 12.
Secondary outcome [11] 305230 0
Biomedical: systolic blood pressure and diastolic blood pressure.

Measured using a automated, calibrated sphygmomanometer.
Timepoint [11] 305230 0
Baseline, week 6 and 12.
Secondary outcome [12] 305231 0
Behavioural: Physical activity behaviour.

Measured using the International Physical Activity Questionnaire (IPAQ).

Also, measured using a three consecutive day food and exercise diary.
Timepoint [12] 305231 0
Baseline, week 6 and 12.
Secondary outcome [13] 305232 0
Behavioural: Diet habits behaviour.

Measured using a three consecutive day food and exercise diary.
Timepoint [13] 305232 0
Baseline, week 6 and 12.
Secondary outcome [14] 305235 0
Biomedical: Blood lipoproteins (LDL, HDL, total cholesterol, TG) glucose, insulin.

Blood samples will be collected by a trained phlebotomist via venepuncture from patients in the fasting state.
Timepoint [14] 305235 0
Baseline, 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
Gender
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)
The principal researcher will be involved in the participant recruitment process and ensure whether participants met the study inclusion criteria. A list of the names and contact details of the participants who met the study inclusion criteria will be provided to a research assistant.

The research assistant will randomly allocate participants to one of three group conditions using a computer-generated schedule. This process will be conducted by an research assistant to ensure participant allocation is concealed. Based on identification numbers participants will be assigned to their number condition (1, 2, or 3) by the research assistant. 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 principle 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
Parallel
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
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
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.
Address [1] 287354 0
Postal Address:
GPO Box U1987 Perth,
Western Australia 6845
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
Individual
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
Individual
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
Approved
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
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

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
+61 456 103 197
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