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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
A healthy nest is best (NEST): The effects of bedding, insulation and heating on infant respiratory health
Scientific title
A multi arm, parallel, randomised, active-controlled primary prevention study examining how improving home insulation and heating, and use of different types of bedding (feather, wool, synthetic), might prevent wheezing in the first 2 years of life.
Secondary ID [1] 287512 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Prevention of wheezing in the first 2 years of life 296271 0
Condition category
Condition code
Respiratory 296545 296545 0 0
Inflammatory and Immune System 296546 296546 0 0

Study type
Description of intervention(s) / exposure
Participants will be randomly assigned to one of three bedding intervention groups; receiving either feather, wool or synthetic sleepsacks for their infant to use to sleep in during their first 2 years of life. All participants will receive a heating voucher of $200 to their power accounts to use during their infants first winter. Parents will be given advice about what temperature to heat infant bedrooms to, based on WHO guidelines (18-22°C). Participants will be contacted every 6 months to remind them to use the sleepsacks.
Intervention code [1] 292902 0
Comparator / control treatment
The comparator group in this study is the synthetic bedding group, which is an active control for the wool and feather bedding groups.
Control group

Primary outcome [1] 296169 0
The primary outcome measure will be a parental reported history of wheezing in the first two years of life.
Timepoint [1] 296169 0
Parents will be interviewed about their child's wheezing history, using standard ISAAC questions, when their child is 2 years old.
Secondary outcome [1] 317683 0
General Practitioner (Doctor) prescribed oral steroids or inhaled medications for wheezing by aged 2 years.
Timepoint [1] 317683 0
General practitioner records will be searched when child is 2 years old.
Secondary outcome [2] 317684 0
A positive allergen response to one or more of a panel of 6 common environmental and food allergens by 2 years of age. A positive response will be defined as a mean wheal size >= 3 mm to any allergen after subtraction of the negative control.
Timepoint [2] 317684 0
Allergen testing will be conducted when the child is 2 years old.
Secondary outcome [3] 317716 0
General practitioner visits for upper and lower respiratory tract infections.
Timepoint [3] 317716 0
GP record search when child is 2 years old.
Secondary outcome [4] 317717 0
General practitioner visits for wheezing.
Timepoint [4] 317717 0
General practitioner record search when child is 2 years old.
Secondary outcome [5] 317718 0
General practitioner prescriptions for antibiotics.
Timepoint [5] 317718 0
GP record search when child is 2 years old.
Secondary outcome [6] 317719 0
Number of general practitioner diagnoses of Otitis media.
Timepoint [6] 317719 0
GP record search when child is 2 years old.
Secondary outcome [7] 317720 0
Number of general practitioner diagnoses with croup.
Timepoint [7] 317720 0
GP record search when child is 2 years old.

Key inclusion criteria
Pregnant mothers in their second or third trimester of pregnancy from the Wellington region. All infants will be included.
Minimum age
No limit
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Families who plan to move out of the Wellington region in the next 18 months. Pregnant mothers under 18 years of age.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Potential participants will be identified by the staff of Parents as First Teachers (Naku Enei Tamariki Boards), who see pregnant women as part of the services they provide. Mothers will be invited to take part in the study and will be provided with a detailed information sheet. Those that are willing and eligible will be enrolled into the study. Participants will be randomly assigned to a bedding group using a computer generated randomisation programme. Allocation concealment will be performed by sealed opaque envelopes. All sleep sacks will be assigned a random number matching that of the computer programme to be given to participants. The researchers do not know which group the participant will be assigned to, so allocation to the study groups is concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Sequence generation will occur by using a randomisation table created by computer software and applied at the time of enrollment.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Power, sampling and analysis: The primary outcome will be a parental reported history of wheezing during the first two years of life. The primary analysis will be will be a multivariate logistic regression with wheezing as defined above as the primary outcome and the sleepsack which was assigned as the independent variable, this model will be adjusted for significant confounders . Secondary outcomes will be similarly analysis by a multivariate logistic model

Power: Our previous population based birth cohort study found the prevalence of reported wheezing in the first 15 months of life was 35%. Each of the three groups will consist of 150 infants. Allowing for 12% loss to follow-up, the proposed study will have 88% power to show an absolute reduction in wheezing from 35% to 20% by any bedding type (alpha 0.05). The secondary outcome of atopy is equally well powered.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 7178 0
New Zealand
State/province [1] 7178 0

Funding & Sponsors
Funding source category [1] 292087 0
Government body
Name [1] 292087 0
Health Research Council (NZ)
Address [1] 292087 0
Level 3, Pro Care Building, Grafton Mews
110 Stanley Street
Auckland 1010
Country [1] 292087 0
New Zealand
Primary sponsor type
Julian Crane
School of Medicine and Health Sciences
University of Otago, Wellington
23a Mein Street
Wellington 6021
New Zealand
Secondary sponsor category [1] 290765 0
Name [1] 290765 0
Address [1] 290765 0
Country [1] 290765 0

Ethics approval
Ethics application status
Ethics committee name [1] 293571 0
Central Health and Disability Ethics Committee
Ethics committee address [1] 293571 0
Ministry of Health
No.1 The Terrace,
PO Box 5013
Wellington 6145
Ethics committee country [1] 293571 0
New Zealand
Date submitted for ethics approval [1] 293571 0
Approval date [1] 293571 0
Ethics approval number [1] 293571 0

Brief summary
Cold and damp housing have been shown in many studies to be linked to asthma in children. We have shown recently that dampness is also related to the onset of wheezing in New Zealand children. In this study we are looking at how improving insulation and heating, and how using different types of infant bedding, might help prevent wheezing and asthma in young children. This research is part of He Kainga Oranga Housing and Health Research Programme conducted by the University of Otago Wellington, funded by the Health Research Council of New Zealand.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 60498 0
Prof Julian Crane
Address 60498 0
Dept of Medicine
University of Otago, Wellington
23a Mein Street
Wellington 6021
Country 60498 0
New Zealand
Phone 60498 0
Fax 60498 0
Email 60498 0
Contact person for public queries
Name 60499 0
Dr Caroline Shorter
Address 60499 0
Dept of Medicine
University of Otago, Wellington
23a Mein Street
Wellington 6021
Country 60499 0
New Zealand
Phone 60499 0
Fax 60499 0
Email 60499 0
Contact person for scientific queries
Name 60500 0
Prof Julian Crane
Address 60500 0
Dept of Medicine
University of Otago, Wellington
23a Mein Street
Wellington 6021
Country 60500 0
New Zealand
Phone 60500 0
Fax 60500 0
Email 60500 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Consent wasn't sought from participants to do this.
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary