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Trial registered on ANZCTR

Registration number

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]

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

Condition category

Condition code

Diet and Nutrition

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]

Lifestyle

Intervention code [2]

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]

Biomedical outcomes: Body weight (kg).

Measured using a digital body composition monitor scale

Timepoint [1]

Baseline, week 6 and 12.

Primary outcome [2]

Biomedical: Body fat percentage.

Measured using a total body scanner named Dual-energy X-ray absorptiometry (DEXA).

Timepoint [2]

Baseline, week 6 and 12.

Secondary outcome [1]

Biomedical: bone mass.

Measured using a total body scanner named Dual-energy X-ray absorptiometry (DEXA).

Timepoint [1]

Baseline, week 6 and 12.

Secondary outcome [2]

Psychological: Quality of life

Measured using the The Impact of Weight on Quality of Life Questionnaire (IWQOL - Lite).

Timepoint [2]

Baseline, week 6 and 12.

Secondary outcome [3]

Psychological: Risk perception.

Measured using items adapted from Barg and colleagues (2012) study questionnaire.

Timepoint [3]

Baseline, post-intervention, week 6 and 12.

Secondary outcome [4]

Psychological: intention.

Measured using items adapted from Barg and colleagues (2012) study questionnaire.

Timepoint [4]

Baseline, post-intervention, week 6 and 12.

Secondary outcome [5]

Psychological: motivation.

Measured using items adapted from Hagger and colleagues (2012) study questionnaire.

Timepoint [5]

Baseline, post-intervention, Week 6 and 12.

Secondary outcome [6]

Psychological: planning.

Measured using an items adapted from Barg and colleagues (2012) study questionnaire.

Timepoint [6]

Baseline, post-intervention, Week 6 and 12.

Secondary outcome [7]

Psychological: self efficacy.

Measured using items adapted from Barg and colleagues (2012) study questionnaire.

Timepoint [7]

Baseline, post-intervention, week 6 and 12.

Secondary outcome [8]

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]

Baseline, post-intervention, week 6 and 12.

Secondary outcome [9]

Psychological: outcome expectancies.

Measured using an items adapted from Barg and colleagues (2012) study questionnaire.

Timepoint [9]

Baseline, post-intervention, week 6 and 12.

Secondary outcome [10]

Psychological: Depression, anxiety, stress symptoms.

Measured using the Depression Anxiety Stress Scale (DASS -21) by Lovibond and Lovibond (1995).

Timepoint [10]

Baseline, week 6 and 12.

Secondary outcome [11]

Biomedical: systolic blood pressure and diastolic blood pressure.

Measured using a automated, calibrated sphygmomanometer.

Timepoint [11]

Baseline, week 6 and 12.

Secondary outcome [12]

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]

Baseline, week 6 and 12.

Secondary outcome [13]

Behavioural: Diet habits behaviour.

Measured using a three consecutive day food and exercise diary.

Timepoint [13]

Baseline, week 6 and 12.

Secondary outcome [14]

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]

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

Sex

Both males and females

Can healthy volunteers participate?

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

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)

Recruitment postcode(s) [1]

6102 - Bentley

Recruitment postcode(s) [2]

6982 - Bentley

Funding & Sponsors

Funding source category [1]

University

Name [1]

Curtin University of Technology, Bentley.

Address [1]

Postal Address:
GPO Box U1987 Perth,
Western Australia 6845

Country [1]

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]

None

Name [1]

Address [1]

Country [1]

Other collaborator category [1]

Individual

Name [1]

Dr Martin Hagger

Address [1]

School of Psychology

Curtin University of Technology, Bentley

GPO Box U1987 Perth,
Western Australia 6845

Country [1]

Australia

Other collaborator category [2]

Individual

Name [2]

Associate Professor Sebely Pal

Address [2]

School of Public Health

Curtin University of Technology, Bentley

GPO Box U1987 Perth,
Western Australia 6845

Country [2]

Australia

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Human Research Ethics

Ethics committee address [1]

Curtin University of Technology
The Secretary, HREC
Office of Research and Development
PO Box U1987
Perth WA 6845

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

03/09/2013

Approval date [1]

16/09/2013

Ethics approval number [1]

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

Ms Anne Hattar

Address

Anne Hattar / Martin Hagger

Curtin University of Technology
School of Psychology
GPO Box U1987
Perth Western Australia 6845

Country

Australia

Phone

+61 456 103 197

Fax

[email protected]

Contact person for public queries

Name

Anne Hattar

Address

Anne Hattar / Martin Hagger

Curtin University of Technology
School of Psychology
GPO Box U1987
Perth Western Australia 6845

Country

Australia

Phone

+61 456 103 197

Fax

[email protected]

Contact person for scientific queries

Name

Martin Hagger and Sebely Pal

Address

Curtin University of Technology
School of Psychology
GPO Box U1987
Perth Western Australia 6845

Country

Australia

Phone

+61 08 92662215

Fax

[email protected]; [email protected]

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

Type	Is Peer Reviewed?	DOI	Citations or Other Details	Attachment
Study results article	Yes		Hattar, A., Hagger, M. S., and Pal, S. (2016). Pre... [More Details]

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Weight-loss intervention using implementation intentions and mental imagery: a randomised control trial study protocol.	2015	https://dx.doi.org/10.1186/s12889-015-1578-8

N.B. These documents automatically identified may not have been verified by the study sponsor.

Trial Review

Documents added manually

Documents added automatically