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Trial registered on ANZCTR


Registration number
ACTRN12621000906853p
Ethics application status
Not yet submitted
Date submitted
4/05/2021
Date registered
13/07/2021
Date last updated
13/07/2021
Date data sharing statement initially provided
13/07/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
Short-term exposure to biodiversity and health in children with asthma
Scientific title
Does short-term exposure to biodiversity affect gut microbiota, immunity, and asthma and allergy symptoms in children with asthma?
Secondary ID [1] 304126 0
None
Universal Trial Number (UTN)
Trial acronym
STEALTH (Short Term Exposure to biodiversity and heALTH in children with asthma)
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Allergic asthma 321812 0
Asthma 321813 0
Allergy 321814 0
Condition category
Condition code
Respiratory 319542 319542 0 0
Asthma
Inflammatory and Immune System 319543 319543 0 0
Allergies

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants will be randomly assigned to two groups of the same size, with one (intervention group) asked to visit a high vegetation diverse area (described below) at least twice, and for a minimum of 2 hours a week, for a 3-month period. For these periods they will be asked to walk/spend time in close proximity to vegetation. The other group (control) will conduct themselves as normal, but whenever possible, avoid pre-identified areas of high biodiversity for the same 3-month period. During this period participants will be asked to keep a diary of their visits and we will collect admission data from Zealandia to determine adherence. At the end of the 3-month period, all participants will be assessed. Participants will then be asked to return to normal behaviour (with associated exposures) for the following nine-month period (“washout”). At the same time the following year (to control for environmental variation/pollen exposure), participants will be asked to “crossover”, and undergo the corresponding exposure (i.e. children previously asked to visit biodiverse areas would now be requested to avoid them and vice versa). Local areas of high native vegetation diversity around Wellington, New Zealand (including Zealandia ecosanctuary) will be used as the site of high biodiverse exposure. Vegetation diversity will be quantified using normalised difference vegetation index (NDVI) and the Land-Cover Database (Landcare Research NZ),
Intervention code [1] 320460 0
Treatment: Other
Comparator / control treatment
As this is a crossover trial, both groups will undergo a period of intervention and control. The control arm will be provided with details of areas of high vegetation diversity which they should avoid, and asked to stay at least 100m from these areas, They will be asked to keep a diary to record any instances in which they had to be in high vegetation diverse areas.
Control group
Active

Outcomes
Primary outcome [1] 327401 0
Change in asthma control questionnaire (ACQ-7) score
Timepoint [1] 327401 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period
Primary outcome [2] 328018 0
Change in asthma and allergy symptoms (as assessed by International Study on Allergies and Asthma in Childhood (ISAAC) Phase II survey)
Timepoint [2] 328018 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period
Primary outcome [3] 328019 0
Change in Fractional Exhaled Nitric Oxide (FENO) levels- assessed using a FENO analyser
Timepoint [3] 328019 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period
Secondary outcome [1] 394971 0
Change in lung function (FEV1, FVC, FEV1/FVC) as assessed by spirometry
Timepoint [1] 394971 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period
Secondary outcome [2] 397234 0
Change in peak expiratory flow (PEF) variability as assessed by spirometry and PEF meters
Timepoint [2] 397234 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period
Secondary outcome [3] 397235 0
Change in blood markers (serum cytokines (IL-5, IL-6, IL-10, IL-13, IL-17, IFN-g, TNF-a) assessed by cytokine bead array, and complete blood count-assessed using a haematology analyser)
Timepoint [3] 397235 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period
Secondary outcome [4] 397236 0
Change in gut microbiome characteristics, as assessed by 16s sequencing
Timepoint [4] 397236 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period
Secondary outcome [5] 397237 0
Change in wellbeing (based on World Health Organisation (WHO)-5 questionnaire)
Timepoint [5] 397237 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period
Secondary outcome [6] 397238 0
Change in Nature Connection Index (NCI) score-assessed using the NCI questionnaire
Timepoint [6] 397238 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period
Secondary outcome [7] 398134 0
Change in wellbeing (based on Kessler-6 questionnaire)
Timepoint [7] 398134 0
Baseline; 3 months after initiation of intervention period; 3 months after initiation of control period

Eligibility
Key inclusion criteria
Doctor's diagnosis of asthma and reported wheeze in the last 12 months
Minimum age
11 Years
Maximum age
16 Years
Gender
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Other significant cardiac or pulmonary diseases.
Regular use of oral corticosteroid medication.

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)
Allocation is not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation will be done using a randomisation table created by computer software (i.e. computerised sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Based on studies in which subjects completed the asthma control questionnaire (ACQ7) repeatedly over time, we assume a within-subject variance of the ACQ score to be 0.18 with a mean ACQ score of 1.49. With a total of 50 asthma subjects (25 in each arm; we will oversample by 20% to compensate for loss-to-follow up) we will have 80% power to detect a 6% difference and 90% power to detect a 12% difference in ACQ score. For other outcomes, study power is likely to be less, but sufficient to demonstrate general trends.

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 outside Australia
Country [1] 23672 0
New Zealand
State/province [1] 23672 0
Wellington

Funding & Sponsors
Funding source category [1] 308504 0
Government body
Name [1] 308504 0
NZ Health Research Council - Sir Charles Hercus Fellowship
Address [1] 308504 0
Health Research Council
PO Box 5541
Victoria Street West
Auckland
1142
Country [1] 308504 0
New Zealand
Primary sponsor type
University
Name
Research Centre for Hauora and Health (Formerly Centre for Public Health Research), Massey University
Address
Research Centre for Haurora and Health
Massey University Wellington Campus
PO Box 756
Wellington 6140
Country
New Zealand
Secondary sponsor category [1] 309358 0
None
Name [1] 309358 0
Address [1] 309358 0
Country [1] 309358 0

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 308465 0
Health and Disability Ethics Committee (specific committee to be confirmed), Ministry of Health.
Ethics committee address [1] 308465 0
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140
Ethics committee country [1] 308465 0
New Zealand
Date submitted for ethics approval [1] 308465 0
01/09/2021
Approval date [1] 308465 0
Ethics approval number [1] 308465 0

Summary
Brief summary
The purpose of the study is to determine if short-term exposure to biodiverse environments modulates or affects gut microbiota, immune responses, FENO, lung function and asthma and allergy symptoms in a group of children with asthma. We hypothesise that exposure to biodiversity may improve asthma symptoms and control, and that this effect may be driven by the more abundant and numerous bacteria present in biodiverse environments.
Trial website
Trial related presentations / publications
Public notes
As this is a crossover trial, all participants will undergo intervention and control periods; they will simply be randomly assigned to the two crossover groups.

Contacts
Principal investigator
Name 110782 0
Dr Collin Brooks
Address 110782 0
Research Centre for Hauora and Health
Massey University Wellington Campus
Private Bag 756
Wellington
6140
Country 110782 0
New Zealand
Phone 110782 0
+64 4 9793093
Fax 110782 0
Email 110782 0
c.r.brooks@massey.ac.nz
Contact person for public queries
Name 110783 0
Dr Collin Brooks
Address 110783 0
Research Centre for Hauora and Health
Massey University Wellington Campus
Private Bag 756
Wellington
6140
Country 110783 0
New Zealand
Phone 110783 0
+64 4 9793093
Fax 110783 0
Email 110783 0
c.r.brooks@massey.ac.nz
Contact person for scientific queries
Name 110784 0
Dr Collin Brooks
Address 110784 0
Research Centre for Hauora and Health
Massey University Wellington Campus
Private Bag 756
Wellington
6140
Country 110784 0
New Zealand
Phone 110784 0
+64 4 9793093
Fax 110784 0
Email 110784 0
c.r.brooks@massey.ac.nz

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
No IPD will be shared for ethical reasons.
What supporting documents are/will be available?
No other documents available
Summary results
No Results