Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12624000101583p
Ethics application status
Submitted, not yet approved
Date submitted
15/12/2023
Date registered
6/02/2024
Date last updated
6/02/2024
Date data sharing statement initially provided
6/02/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
Evaluation of the effectiveness of air purification in reducing indoor air pollution and asthma deterioration in households with a member who has asthma: a randomized control trial.
Scientific title
Evaluation of the effectiveness of air purification in reducing indoor air pollution and asthma deterioration: a randomized, double-blind, placebo-controlled crossover trial
Secondary ID [1] 310347 0
Nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Asthma 331090 0
Air quality 331091 0
Condition category
Condition code
Respiratory 327877 327877 0 0
Asthma

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The proposed study is a randomised placebo-controlled crossover trial
Twenty households including at least one member with asthma will be recruited so that half of the households have actively used wood heaters and the other half have an electrical form of heating (e.g., reverse cycle/split system air conditioning). The households will be initially randomised into two groups
(A- air purifiers with filters-intervention) & (B-air purifiers without filters-placebo) at a 1 (wood heater):1 (non-wood heater) ratio.

After two weeks, the groups will be switched: Group A will have their active filter changed for a dummy filter, and Group B will have their dummy filter changed for an active filter. This will occur two more times so that each of the two groups experience two intervention periods (2 x 2 weeks) and two placebo periods (2 x 2 weeks). The study team will change the filter on the air cleaner in each participating household each fortnight, at the same time as the fortnightly visits.

All households will have air quality measurements collected in the main living room or the room containing the wood heater. Both the participants and investigators will be blinded to the intervention assignment in each of the study-groups. To ensure that the study is double blind (and the air purifiers are indistinguishable from each other) someone unrelated to the study will install either a HEPA filter or blank cartridge in each purifier. The date and time the filter is changed will be recorded by the study team.

The air quality monitoring will run continuously over the intervention period. Each household member will record in a daily diary the time spent at home. There is no minimum requirement for exposure to air purification to reflect the fact that this is a real-world intervention and as such the study team aims to replicate real world exposures.
Intervention code [1] 327082 0
Prevention
Comparator / control treatment
air purifiers without filters-placebo for 2 weeks at 2 different timepoints.
Control group
Placebo

Outcomes
Primary outcome [1] 336190 0
levels of PM2.5 air pollution in homes with hepa filtration and activated carbon air purification compared to homes without hepa filtration and active carbon filtration will be assessed using air quality monitors.
Timepoint [1] 336190 0
Baseline, and post-intervention at 2 weeks 4 weeks (primary timepoint), 6 weeks and 8 weeks
Primary outcome [2] 336895 0
Differences in levels of indoor pollution Indoor air pollution (PM2.5) between houses with wood heaters and houses with electrical heating. This will be measured indoor and outdoor air quality monitors, which will transmit data every 10 minutes to a secure cloud based data repositiry.
Timepoint [2] 336895 0
Baseline. post intervention at 2 weeks, 4 weeks (primary timepoint) , 6 weeks and 8 weeks
Primary outcome [3] 336897 0
respiratory symptom control (asthma symptom control) based on self report using Asthma Control Questionnaire and Asthma Quality of Life Questionnaire
Timepoint [3] 336897 0
baseline and post intervention at 2 weeks, 4 weeks, 6 weeks and 8 weeks
Secondary outcome [1] 430050 0
Nil
Timepoint [1] 430050 0
Nil

Eligibility
Key inclusion criteria
1. 10 homes with wood heaters
2. 10 homes electrical heating
3. at least one member diagnosed with asthma with symptoms
4. age range 11-80 years
5. willing to participate in daily spirometry and questionairres for 8 week period between June and August 2024,
Minimum age
11 Years
Maximum age
80 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
1. Households which use gas heating or gas cooking'
2. Homes with a main living room of less than 100m2
3. Households which have a tobacco smoker who smokes indoors

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)
sealed in opaque envelope
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
simple randomisation using computer generated sequence
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis
The statistical analyses will involve linear and generalised linear mixed models to estimate differences in PM2.5 levels and asthma outcomes between the intervention groups, and by wood heater/non-wood heater groups, accounting for the repeated measurements across participants and households.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
15/03/2024
Actual
Date of last participant enrolment
Anticipated
17/06/2024
Actual
Date of last data collection
Anticipated
16/09/2024
Actual
Sample size
Target
20
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 314554 0
Government body
Name [1] 314554 0
Department of Planning an Environment
Country [1] 314554 0
Australia
Funding source category [2] 315453 0
Government body
Name [2] 315453 0
National Health and Medical Research Council
Country [2] 315453 0
Australia
Primary sponsor type
University
Name
Australian National University
Address
Canberra ACT 2600
Country
Australia
Secondary sponsor category [1] 316511 0
None
Name [1] 316511 0
Address [1] 316511 0
Country [1] 316511 0

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 313591 0
Australian National University Human Research Ethic Committee
Ethics committee address [1] 313591 0
Canberra, ACT 2600
Ethics committee country [1] 313591 0
Australia
Date submitted for ethics approval [1] 313591 0
14/12/2023
Approval date [1] 313591 0
Ethics approval number [1] 313591 0

Summary
Brief summary
The aim of this pilot study (n=20) is to better understand the impact of wood heaters on residential air quality as well as the effectiveness of portable air cleaners in improving indoor air quality and asthma and health symptoms. Indoor and outdoor air quality monitors will be placed in homes to measure fine particles in air (particulate matter (PM2.5) - this is a component of woodsmoke that results in poor air quality. We will also place small metal sampling tubes inside and outside your home to measure concentrations of volatile chemicals (volatile organic compounds (VOCs), which also contribute to poor air quality. Monitoring will be conducted for two months during winter. The air quality monitors transmit their data every 10 minutes to a secure cloud-based data repository.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 128670 0
Prof Sotiris Vardoulakis
Address 128670 0
Australian National University 62 Mills Rd Canberra ACT 2601.
Country 128670 0
Australia
Phone 128670 0
+61 490 711 964
Fax 128670 0
Email 128670 0
[email protected]
Contact person for public queries
Name 128671 0
Nigel Goodman
Address 128671 0
AUstralian National University, 62 Mills Rd Canberra ACT 2601
Country 128671 0
Australia
Phone 128671 0
+61 424 587 121
Fax 128671 0
Email 128671 0
[email protected]
Contact person for scientific queries
Name 128672 0
Nigel Goodman
Address 128672 0
Australian National University, 62 Mills Rd Canberra ACT 2601
Country 128672 0
Australia
Phone 128672 0
+61 424 587 121
Fax 128672 0
Email 128672 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
All de-identified line item data
When will data be available (start and end dates)?
immediately following publication, no end date yet determined.
Available to whom?
Researchers who submit a sound research proposal to the principal investigator
Available for what types of analyses?
IPD meta analyses
How or where can data be obtained?
Contact [email protected]


What supporting documents are/will be available?

Doc. No.TypeCitationLinkEmailOther DetailsAttachment
21221Study protocol  [email protected]
21222Informed consent form  [email protected]
21223Ethical approval  [email protected]



Results publications and other study-related documents

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