Trial Review

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Trial registered on ANZCTR


Registration number
Help: Registration number
ACTRN12626001107314
Ethics application status
Help: Ethics application status
Approved
Date submitted
Help: Date submitted
19/08/2026
Date registered
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8/09/2026
Date last updated
Help: Date last updated
8/09/2026
Date data sharing statement initially provided
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8/09/2026
Type of registration
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Prospectively registered

Titles & IDs
Public title
Let’s Grow+: A mHealth intervention to enhance nutrition and movement behaviours in toddlers.
Scientific title
A randomised controlled trial (RCT) assessing the efficacy and cost-effectiveness of a mobile health (mHealth) intervention targeting nutrition and movement behaviours (sedentary behaviour, physical activity and sleep) in toddlers and their parents.
Additional trial identifiers [1] 318234 0
MRFF Maternal Health and Healthy Lifestyles - 2031053
Universal Trial Number (UTN)
Trial acronym
Let's Grow+
Related trial records

Health condition
Health condition(s) studied:
Sedentary behaviour 337824 0
Poor nutrition 337826 0
Physical inactivity 337827 0
Sleep 337828 0
Condition category
Condition code
Public Health 334161 334161 0 0
Health promotion/education

Intervention/exposure
Study type
Interventional
Description of the intervention or exposure
Intervention content will be delivered via an app (named “Let’s Grow”) and push notifications. Participants in the intervention group will work through 8 behaviour change modules within the app at their own pace and in whatever order they choose. Each module contains content on parenting and a combination of nutrition and movement behaviours (physical activity, sedentary behaviour and sleep) provided via infographics and short videos. Each module also contains a range of behaviour change activities for families to undertake online (e.g. create a bedtime routine), offline (e.g. practice a fundamental movement skill daily for a week) and a combination of both (e.g. app helps set a goal around increasing vegetable intake, attaining the goal occurs offline with notifications prompting and supporting goal adherence). In addition, core content is contained within an "Explore" page e.g. parenting strategy videos, play ideas, recipes. Intervention content has been developed by a team of experts and incorporates practical advice, established behaviour change techniques (e.g., goal setting, self-monitoring), and tips and tools to assist parents/caregivers to improve their child’s nutrition, physical activity, sleep and sedentary behaviour. Module content takes approximately 10min to read/view; the behaviour change activities conducted offline with assistance from notifications are undertaken over a period of up to 3 weeks per module. The intervention phase will last 6 months.

Parents will also receive push notifications over the course of the intervention to assist with monitoring progress of ongoing activities (e.g. goal setting and self monitoring), to remind them of key messages, and to push them back to app content. Notifications will be personalised to include the parent and child names and their chosen goal/s (where appropriate).

Intervention adherence will be monitored by app usage data. An automated notification will be sent 1 week after first log in if no modules have been started, to encourage participants to engage and complete the program. If there is continued inactivity, research staff will contact participants to encourage continuation of the program.
Intervention code [1] 331282 0
Lifestyle
Intervention code [2] 331283 0
Behaviour
Description of the comparator or control
The control group will not have access to the app. Instead, they will receive monthly electronic newsletters on unrelated topics, such as common childhood illnesses, basic first aid, and typical parent concerns like hearing or speech development. These newsletters have been designed specifically by researchers for the study and will be distributed throughout the 6-month intervention period to support cohort retention.
Control group
Active

Outcomes
Primary outcome [1] 341813 0
Child diet quality score.
Timepoint [1] 341813 0
Baseline (T0, Pre-randomisation); mid-intervention (T1, 3 months after randomisation), end of intervention (T2 – primary timepoint, 6-months after randomisation); 6-months post intervention follow-up (T3, 12 months after randomisation)
Primary outcome [2] 341814 0
Average daily proportion of time the child spent in physical activity, sedentary behaviour and sleep (composite outcome).
Timepoint [2] 341814 0
Baseline (T0, Pre-randomisation); mid-intervention (T1, 3 months after randomisation), end of intervention (T2 – primary timepoint, 6-months after randomisation); 6-months post intervention follow-up (T3, 12 months after randomisation)
Secondary outcome [1] 448760 0
Parental diet quality score
Timepoint [1] 448760 0
Baseline (T0, Pre-randomisation); mid-intervention (T1, 3 months after randomisation), end of intervention (T2 – primary timepoint, 6-months after randomisation); 6-months post intervention follow-up (T3, 12 months after randomisation)
Secondary outcome [2] 452070 0
Average daily proportion of time the parent/caregiver spent in physical activity, sedentary behaviour and sleep (composite outcome).
Timepoint [2] 452070 0
Baseline (T0, Pre-randomisation); mid-intervention (T1, 3 months after randomisation), end of intervention (T2 – primary timepoint, 6-months after randomisation); 6-months post intervention follow-up (T3, 12 months after randomisation)
Secondary outcome [3] 467043 0
Economic evaulation
Timepoint [3] 467043 0
All timepoints. Baseline (T0, Pre-randomisation); mid-intervention (T1, 3 months after randomisation), end of intervention (T2 – primary timepoint, 6-months after randomisation); 6-months post intervention follow-up (T3, 12 months after randomisation). Within-trial CEA and CUA; modelled evaluation.

Eligibility
Key inclusion criteria
Parent or primary caregiver of a child aged between 18-35 months, resides in Australia, has a web-enabled mobile phone, can complete assessments in English and child is walking.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Healthy volunteers
Yes
Key exclusion criteria
Children who are not yet walking independently.

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)
Automated concealed allocation by software.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computerised generation of 14 sequences to allow stratified allocation based on geographical location (state and city/regional city vs rural/remote)
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
We aim to recruit 800 families to ensure complete T2 survey data on approximately 600 children and parents/caregivers (75% retention) and valid accelerometery data (greater than or equal to 4 days) on around 480 participants (60% valid data). Retention estimates are conservative and informed by previous early childhood trials, which achieved 86–89% retention over 15 months to 2 years and 82% valid accelerometer data at baseline in Let’s Grow (ACTRN12620001280998). This sample size will provide at least 80% power to detect meaningful changes in our primary outcomes (child behaviours) and secondary outcomes (parent behaviours) at T2.

The co-primary outcomes in children are diet quality (DGI score) and movement behaviours (alpha=0.025 to account for two primary outcomes). For diet quality, 600 children (300 per group) will provide 80% power to detect an increase of 3.5 units in DGI score at T2 (SD=14, two-sided t-test), equivalent to just over one extra serve of vegetables per day in children. For movement behaviours, compositional analyses of accelerometery data will be undertaken. Log- ratio transformed time-use movement data at T2. Assuming in the control group the proportion of daily time spent in physical activity (PA), sedentary behaviour (SB) and sleep is 16.9%, 28.1% and 55.0% respectively, 480 children (240 per group) achieves 85% power to detect an increase of 15min/day in PA accompanied by a 15min/day decrease in SB (log-ratio scale: +0.060 PA, –0.038 SB; covariance matrix [var(1)=0.087, var(2)=0.028, covar(1,2)=0.007]; Hotelling's T-squared test statistic).

Secondary outcomes will be assessed in parents/caregivers (alpha=0.05). For diet quality, 600 parents/caregivers will provide 80% power to detect an increase of 3.6 units in DGI score (SD=14.540, two-sided t-test). A change of 2 units corresponds to one extra serve of vegetables per day in adults. Log-ratio transformed time-use movement data at T2. Assuming the proportion of time spent in PA, SB and sleep in the control group is 19%, 48% and 33% respectively; a sample of 480 parents achieves 85% power to detect a daily increase of 19min in any type of PA accompanied by a 19min decrease in SB (log-ratio scale: +0.063 PA, –0.026 SB; covariance matrix [var(1)=0.076, var(2)=0.047, covar(1,2)=0.0011]; Hotelling's T-squared test statistic).

All analyses will be conducted on an intention-to-treat basis. Intervention effects on parental and child DGI scores will be estimated using linear mixed models with participant as a random effect. Movement behaviour data will be analysed using compositional approaches, Proportion of time-use data will be transformed into log-ratios; the fraction of daily time spent in physical activity (x1), sedentary behaviour (x2) and sleep (x3) will be transformed to new variables y1=log(x1/x3) and y2=log(x1/x3) using the proportion of time spent sleeping as a reference. This transformation converts the vector of proportions (x1, x2, x3), which sum to 1, into a bi-dimensional vector (y1, y2) whose components are no longer constrained and can be analysed using standard multivariate data analysis. The intervention effect on the log-ratio transformed time-use data will be estimated using a multivariate linear mixed-effect model with trial arm as fixed effect and a 2×2 unstructured variance-covariance matrix to account for the correlation between components’ proportions. To facilitate interpretation, estimated mean log-ratios will be back transformed into proportion of time (minutes/day) in each behaviour. We will further estimate the longitudinal effect of the intervention on the log-ratio transformed proportions using a multivariate linear mixed-effect model with trial arm, time (T0, T1, T2, T3) and interaction arm × time as fixed effects, child as a random effect to account for the repeated measures, and a 2×2 unstructured variance-covariance matrix.

Mediation analyses will be conducted within a counterfactual framework, with indirect effects estimated using G-estimation while adjusting for confounders of the mediator–outcome association.

An incremental cost-effectiveness analysis will also be undertaken to determine whether the intervention represents value for money compared to control. This will involve assessing both net cost and net health benefit, and will identify key design features and cost drivers of the intervention through a trial-based economic evaluation.

Process data collected from the intervention group, including app usage information and parent/caregiver reported engagement with the program, will be analysed descriptively.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
19/10/2026
Actual
Date of last participant enrolment
Anticipated
19/10/2027
Actual
Date of last data collection
Anticipated
31/12/2028
Actual
Sample size
Target
800
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
ACT,NSW,NT,QLD,SA,TAS,WA,VIC

Funding & Sponsors
Funding source category [1] 319207 0
Government body
Name [1] 319207 0
Australian Department of Health, Disability and Ageing, Medical Research Future Fund (MRFF)
Country [1] 319207 0
Australia
Primary sponsor type
University
Name
Deakin University
Address
Country
Australia
Secondary sponsor category [1] 322369 0
None
Name [1] 322369 0
None
Address [1] 322369 0
Country [1] 322369 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 317785 0
Deakin University Human Research Ethics Committee (DUHREC)
Ethics committee address [1] 317785 0
Ethics committee country [1] 317785 0
Australia
Date submitted for ethics approval [1] 317785 0
26/03/2025
Approval date [1] 317785 0
12/06/2025
Ethics approval number [1] 317785 0
2024/HE000771

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

Contacts
Principal investigator
Name 142146 0
Prof Kylie Hesketh
Address 142146 0
Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences. Deakin University, 221 Burwood Highway, Burwood VIC 3125
Country 142146 0
Australia
Phone 142146 0
+61392446812
Fax 142146 0
Email 142146 0
[email protected]
Contact person for public queries
Name 142147 0
Savannah Simmons
Address 142147 0
Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences. Deakin University, 221 Burwood Highway, Burwood VIC 3125
Country 142147 0
Australia
Phone 142147 0
+61392445629
Fax 142147 0
Email 142147 0
[email protected]
Contact person for scientific queries
Name 142148 0
Kylie Hesketh
Address 142148 0
Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences. Deakin University, 221 Burwood Highway, Burwood VIC 3125
Country 142148 0
Australia
Phone 142148 0
+61392446812
Fax 142148 0
Email 142148 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
Yes
Will there be any conditions when requesting access to individual participant data?
Persons/groups eligible to request access:
• Researchers
Conditions for requesting access:
• Researchers who provide a methodologically sound proposal, and on a case-by-case basis at the discretion of lead investigator and pending approval from Ethics Committee.

What individual participant data might be shared?
• All de-identified individual participant data
What types of analyses could be done with individual participant data?
• For analysis related to the aims of this study, in line with ethics requirements.

When can requests for individual participant data be made (start and end dates)?
From:
After publication of main results
To:
No end date
Where can requests to access individual participant data be made, or data be obtained directly?
• From lead study investigator: Professor Kylie Hesketh at: [email protected].

Are there extra considerations when requesting access to individual participant data?
No


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.