ClinicalTrials.gg
RecruitingNCT06579950REFLECTUpdated Feb 27, 2026

Assessing the Effects of Cool Roofs on Indoor Environments and Health

An interventional study of Cool roof in Resting Heart Rate, Blood Glucose Control and Depression, sponsored by Aditi Bunker. Recruiting at 5 sites in 5 countries. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-02-27.

Sponsored by Aditi Bunker · Not applicable, Interventional, and Prevention

From the registry’s dates

  • Started Sep 2024; still recruiting 2 years 2 months later.
Phase
Not applicable
Study type
Interventional
Enrollment
3,200
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

Ambient air temperatures in Asian, Latin American, African, and Pacific climate hotspots have broken record highs in 2024, driven by man-made climate change. Solutions are needed to reduce heat exposure in communities. Sunlight-reflecting cool roof coatings passively reduce indoor temperatures and energy use to protect home occupants from extreme heat. Occupants living in poor housing conditions globally - for example in informal settlements, slums, and low-socioeconomic households - are especially vulnerable to increased indoor heat exposure.

Heat exposure can instigate and worsen numerous physical, mental and social health conditions. The worst adverse health effects are being experienced in communities least able to adapt to heat exposure. By reducing indoor temperatures, cool roof use can promote physical, mental and social wellbeing in occupants.

The long-term research goal is to identify viable passive housing adaptation technologies with proven health and environmental benefits to reduce the burden of heat stress in communities affected by heat globally. To meet this goal, the investigators will conduct a cluster-randomized controlled trial to establish the effects of cool roof use on health, indoor environment and economic outcomes in five urban climate hotspots: Ouagadougou, Burkina Faso; Colima, Mexico; Ahmedabad, India; Niue; and Tavua, Fiji.

Read the detailed description

Increasing heat exposure from climate change is causing and exacerbating heat-related illnesses in millions worldwide - particularly in low resource settings. June 2024 was the 13th consecutive hottest month on record globally - shattering previous records. Heat exposure can instigate and worsen health conditions including cardiovascular, metabolic, endocrine and respiratory disease, heat-related illnesses, pregnancy complications, and mental health conditions. Adaptation is essential for protecting people from increasing heat exposure. The built environment, especially our homes, are ideal for deploying interventions to reduce heat exposure and accelerate adaptation efforts. However, currently there is a lack of evidence on a global scale - generated through empirical studies - guiding the uptake of interventions to reduce heat stress in low resource settings.

Sunlight-reflecting cool roof coatings passively reduce indoor temperatures and lower energy use, offering protection to home occupants from extreme heat. The investigators aim to conduct a global multi-centre cluster-randomized controlled trial investigating the effects of cool-roof use on health, environmental and economic outcomes in five urban climate hotspots - Ouagadougou, Burkina Faso (sub-Saharan Africa), Ahmedabad, India (Asia), Tavua, Fiji and Niue (Oceania), and Colima, Mexico (Latin America). The sites represent hotspots where people experience a triple burden from heat exposure, chronic health issues and vulnerable housing conditions (slums, informal settlements and low socioeconomic housing). They also exhibit diversity in climate profiles, housing typology, level of socioeconomic development, population density and rates of urbanisation.

The trial will quantify whether cool roofs are an effective passive home cooling intervention with beneficial health effects for vulnerable populations in four locations. Findings will inform global policy responses on scaling cool roof implementation to protect people from increasing heat exposure driven by climate change.

02

Conditions studied

  • Resting Heart Rate
  • Blood Glucose Control
  • Depression
  • Heat-related Symptoms
  • Physician Diagnosed Heat-related Illnesses
  • Food Insecurity
  • Diet Quality
  • Health-related Quality of Life
  • Indoor Thermal Comfort
  • Coping Ability
  • Life Satisfaction
  • Healthcare Provider Utilization
  • Hospitalization
  • Systolic Blood Pressure
  • Diastolic Blood Pressure
  • Inner Ear Canal Temperature
  • Dehydration
  • Sleep Quality
  • Cognition
  • Productivity
  • Aggression
  • Indoor Air Temperature
  • Indoor Relative Humidity
  • Indoor Heat Index
  • Household Energy Expenditure

Keywords

  • Hot Temperature
  • Humidity
  • Housing
  • Heart rate
  • Cardiovascular
  • Depression
  • Mental health
  • Blood glucose
  • Diabetes
  • Cool roof
  • Heat Stress
03

In context

Depression

8,577 studies on the registry are indexed under Depression; 1,720 are open to participants now.

This study's planned enrollment of 3,200 is above the median of 81 across 7,063 interventional studies indexed under Depression.

Browse Depression studies →

Lead sponsor

Aditi Bunker is the lead sponsor of 7 studies on the registry; 3 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Permanent household resident.

Exclusion criteria

Exclusion Criteria:

  • Roof damage, inaccessible or instability of roof adversely affecting cool roof coating application.
  • Participant unable to provide written/verbal .
Terms in these criteria, in plain language(1)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

05

Study design

Phase
Not applicable
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Double (Investigator, Outcomes assessor)
Enrollment
3,200 participants (estimated)

Study arms

  • Experimental
    Cool roof

    Households will receive sunlight reflecting 'cool roof' coating on their roofs.

    Other: Cool roof

  • No intervention
    No cool roof

    No cool roof application. Households will keep their original roofing for the duration of the trial.

Interventions

  • OtherCool roof

    Cool roofs are a sunlight reflecting roof coating that can reduce indoor temperature. Cool roofs have high solar reflectance (reflecting the ultraviolet and visible wavelengths of sunlight, reducing heat transfer to the surface of a roof) and high thermal emittance (radiating absorbed solar energy).

06

What researchers measure

Primary outcomes

  1. Resting heart rate

    Resting heart rate in beats per minute measured as the average of three readings in the left arm over one hour using Blip portable automated sphygmomanometers.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  2. Blood glucose control

    Three month average of blood glucose in mmol/mol measured as glycosylated hemoglobin (HbA1c) using capillary blood and the HemoCue® HbA1c 501 System.

    Time frame: Two measurements will be taken: one at baseline and one in the last month of three consecutive hottest months.

  3. Depression

    Self-reported presence and frequency of symptoms of depression assessed using aggregate score of the Patient Health Questionnaire 9 (PHQ-9). Minimum score of 0 and a maximum score of 27 with a higher score meaning a worse outcome.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

Secondary outcomes

  1. Heat-related symptoms

    Self-reported heat-related symptoms in the past month, assessed using a recall questionnaire.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  2. Physician diagnosed heat-related illnesses

    Self-reported new diagnosis from a medical practitioner of a heat-related illness in the last month assessed using a recall questionnaire.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  3. Food insecurity

    Self-reported experience based measure of individual food security assessed using the Food Insecurity Experience Scale (FIES).

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  4. Diet quality

    Self-reported individual food group consumption in the previous 24 hours assessed using the Diet Quality Questionnaire (DQQ).

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  5. Health-related quality of life

    Current self-reported health-related quality of life assessed using the EuroQol EQ-5D-5L quality assessment tool. The minimum and maximum scores for the EuroQol EQ-5D-5L quality assessment tool are -0.59 and 1, respectively. A score of 1 represents the best possible health state, while scores below 0 indicate health states that are considered worse than death.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  6. Indoor thermal comfort

    Self-reported household heat, humidity and comfort experience over the last four weeks assessed using a recall questionnaire.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  7. Coping ability

    Self-reported coping strategies for high indoor temperatures assessed using a recall questionnaire.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  8. Life satisfaction

    Current self-reported life satisfaction assessed using the World Values Survey. Values can range from 1 to 10 with a higher score representing greater life satisfaction.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  9. Healthcare provider utilization

    Self-reported healthcare provider utilization in the past four weeks assessed using a recall questionnaire.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  10. Hospitalization

    Self-reported overnight hospital stay in the past four weeks assessed using a recall questionnaire.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  11. Systolic Blood Pressure

    Maximum blood pressure (mmHg) during systole measured as the average of three readings in the left arm over one hour using Blip portable automated sphygmomanometers.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.

  12. Diastolic Blood Pressure

    Minimum blood pressure (mmHg) during diastole measured as the average of three readings in the left arm over one hour using Blip portable automated sphygmomanometers.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.

  13. Cognition

    Accuracy and response time to the four-choice Deary-Liewald Test measured using the CogniFit app-based assessment tool.

    Time frame: Eight measurements: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  14. Inner Ear Canal Temperature

    Internal body temperature (℃) measured once using Braun digital ear thermometer.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.

  15. Dehydration

    Dehydration as indicated by urine specific gravity ≥1.020 measured as urine specific gravity using Siemens Multistix SG dipstick.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  16. Sleep quality

    Self-reported sleep distrubance assessed using the Athens Insomnia Scale (AIS). Values range from 0 to 24 with a higher score indicating a worse outcome.

    Time frame: Eight measurements: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  17. Aggression

    Self-reported personal aggresion assessed using the Buss-Perry Aggression Questionnaire-Ultra Short Form (BPAQ-ML).

    Time frame: Eight measurements: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.

  18. Productivity

    Self-reported job absenteeism and presenteeism assessed using the Health and Work Performance Questionnaire Short Form (HPQ-SF).

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.

  19. Indoor air temperature

    Indoor air temperature (℃) measured using Hobo MX1101 heat and humidity measurement device.

    Time frame: Measurements at 15 minute intervals for 12 months.

  20. Indoor relative humidity

    Ratio of the amount of water vapor present in the air to the greatest amount possible at the same temperature (%) measured using Hobo MX1101 heat and humidity measurement device.

    Time frame: Measurements at 15 minute intervals for 12 months.

  21. Indoor heat index

    Index that combines air temperature and relative humidity (℃) based on temperature and humidity measurements from the Hobo MX1101 heat and humidity measurement device calculated using the formulae endorsed by the US National Oceanic and Atmospheric Administration.

    Time frame: Measurements at 15 minute intervals for 12 months.

  22. Household energy expenditure

    Self-reported household energy expenditure assessed using a recall questionnaire from the head of the household.

    Time frame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.

07

Study locations

1 of 5 sites recruiting
  • University Joseph Ki-Zerbo
    Ouagadougou, Burkina Faso
    Active, not recruiting

    Not enrolling at this site.

  • Fiji National University
    Suva, Fiji
    Recruiting
  • Indian Institute of Public Health Gandhinagar
    Ahmedabad, Gandhinagar, India
    Active, not recruiting

    Not enrolling at this site.

  • Instituto Tecnológico de Hermosillo
    Hermosillo, Sanora, Mexico
    Not yet recruiting
  • Niue
    Alofi, Niue
    Active, not recruiting

    Not enrolling at this site.

08

References and documents

Individual participant data

Plan to share: Yes — Data that can be shared unconditionally underpinning the published research articles will be made available to other researchers at the time of publication, and data will be linked via the article DOI. Data that cannot be unconditionally shared upon publication owing to confidentiality or data protection requirements will be identified as such and a contact email will be provided in relevant publications for data access enquiries by other researchers. Individual names of study participants and identifying factors will be removed prior to data sharing. It is expected that demographic data of people at the study sites (family size and composition, basic socioeconomic indicators) may contain personally identifiable information and location data. All such data will be removed prior to storage on online data repositories and therefore will be available to be publicly shared at the time of publication of manuscripts.

Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report

Time frame: At the time of publication.

Data sharing details ↗ · reflect.org.nz

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Feb 27, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT06579950
Lead sponsor
Aditi Bunker
Collaborators
Sika Services AG, SOPREMA, Engineered Polymer Solutions (EPS B.V.), Resene, Pacific Community, Habitat for Humanity, The Tindall Foundation, Rutgers University, Boston University, London School of Hygiene and Tropical Medicine, Heidelberg University, University of Ouagadougou, Burkina Faso, Indian Institute of Public Health, India, Fiji National University, Universidad de Colima
Responsible party
Aditi Bunker (Co-Principal Investigator, University of Auckland, New Zealand) — Sponsor-investigator
First posted
Aug 30, 2024
Start date
Sep 4, 2024
Primary completion
Sep 30, 2027 (estimated)
Completion
Sep 30, 2027 (estimated)
Last update
Feb 27, 2026

Study contacts

Aditi Bunker, Dr
Contact
aditi.bunker@uni-heidelberg.de
+49 6221 565344
Collin Tukuitonga, Sir. Dr.
Contact
collin.tukuitonga@auckland.ac.nz
+6493737599 ext. 89612
Collin Tukuitonga, Sir. Dr.
principal investigator · University of Auckland, New Zealand

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Interested in this study?

Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.

Contact study team

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Start the discussion