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Completed

NCT Number: NCT06570993

Assessing the Effects of Cool Roofs on Indoor Environments and Health in Niue

Ambient air temperatures in the Pacific have broken record highs in 2024. Solutions are needed to build heat resilience in communities and adapt to increasing heat from climate change. Sunlight-reflecting cool roof coatings may passively reduce indoor temperatures and energy use to protect home occupants from extreme heat. Occupants living in poor housing conditions in the Pacific are susceptible to increased heat exposure.

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

The long-term research goal of the investigators is to identify viable passive housing adaptation technologies with proven health benefits to reduce the burden of heat stress in communities affected by heat in Niue. 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 Niue.

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Key information

Conditions

Resting Heart Rate Aberrant Motor Behavior in Dementia Aggression Behavior Behavioral Symptoms Blood Glucose Control Cognition Coping Ability Dehydration Depression Diabetes Mellitus Diastolic Blood Pressure Diet Quality Dyssomnias Endocrine System Diseases Food Insecurity Glucose Metabolism Disorders Health-Related Quality of Life Healthcare Provider Utilization Heat Stress Disorders Heat-related Symptoms Hospitalization Household Energy Expenditure Indoor Air Temperature Indoor Heat Index Indoor Relative Humidity Indoor Thermal Comfort Inner Ear Canal Temperature Life Satisfaction Mental Disorders Metabolic Diseases Nervous System Diseases Nutritional and Metabolic Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Personal Satisfaction Physician Diagnosed Heat-related Illnesses Productivity Psychological Well-Being Sleep Disorders, Intrinsic Sleep Initiation and Maintenance Disorders Sleep Quality Sleep Wake Disorders Social Behavior Systolic Blood Pressure Water-Electrolyte Imbalance Wounds and Injuries

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Auckland

Auckland, Niue

About this study

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 homes, are ideal for deploying interventions to reduce heat exposure and accelerate adaptation efforts. However, there currently 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.

Pacific Islands and other small island developing states are among the most vulnerable to the adverse impacts of climate change and are likely to experience increases in ambient air temperature over the coming decades. People in Niue are exposed to heat and humidity year-round. The Pacific Islands have a large burden of non-communicable diseases (NCDs), with nearly three-quarters of deaths due to NCDs. The combined burden of heat and NCDs places Pacific Island populations at greater risk of adverse health effects from heat extremes.

Sunlight-reflecting cool roof coatings passively reduce indoor temperatures and lower energy use, offering protection to home occupants from extreme heat. The investigators therefore aim to conduct a cluster-randomized controlled trial investigating the effects of cool-roof use on health, environmental and economic outcomes in Niue.

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

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Participant criteria:

  • Consenting adults aged 18 years and over.
  • Expected to be available to participate in the study for at least nine months in the next 12 months.

Household criteria:

  • House has a metal roof.
  • House is single-story.

Exclusion criteria

Household criteria:

  • Unstable house structure that does not permit the application of cool roof materials.
  • Inaccessible by the research team.
  • Significant roof damage defined as any penetrative roof defect that results in a hole in the roof OR over 25% of the roof rusted.

Treatment and study plan

Cool roof

Other

Cool roofs are a heat-reflecting material that can be applied to existing household roofing in the form of a liquid-applied membrane. Cool roofs work by increasing solar reflectance (the ability to reflect the visible wavelengths of sunlight, reducing heat transfer to the surface) and thermal emittance (the ability to radiate absorbed solar energy) thereby reducing the amount of heat transferred into the home.

Primary outcomes

  1. Resting heart rate

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

    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.

  2. Blood glucose control

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

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

  3. Depression

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

    Self-reported presence and frequency of symptoms of depression assessed using aggregate score of the Patient Health Questionnaire 9 (PHQ-9).

Secondary outcomes

  1. Heat-related symptoms

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

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

  2. Physician diagnosed heat-related illnesses

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

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

  3. Food insecurity

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

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

  4. Diet quality

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

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

  5. Health-related quality of life

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

    Current self-reported health-related quality of life assessed using the EuroQol EQ-5D-5L quality assessment tool.

  6. Indoor thermal comfort

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

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

  7. Coping ability

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

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

  8. 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.

    Current self-reported life satisfaction assessed using the World Values Survey.

  9. Healthcare provider utilization

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

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

  10. Hospitalization

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

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

  11. Systolic Blood Pressure

    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.

    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.

  12. Diastolic Blood Pressure

    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.

    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.

  13. Cognition

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

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

  14. Inner Ear Canal Temperature

    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.

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

  15. Dehydration

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

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

  16. Sleep quality

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

    Self-reported sleep distrubance assessed using the Athens Insomnia Scale (AIS).

  17. Aggression

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

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

  18. Productivity

    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.

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

  19. Indoor air temperature

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

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

  20. Indoor relative humidity

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

    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.

  21. Indoor heat index

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

    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.

  22. Household energy expenditure

    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.

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

Sponsors and collaborators

Lead sponsor

Aditi Bunker

Other

Collaborators

  • Boston University
  • Cognifit
  • Habitat for Humanity
  • Heidelberg University
  • Indian Institute of Public Health, India
  • Labfront
  • London School of Hygiene and Tropical Medicine
  • Pacific Community
  • Resene
  • Rutgers University
  • Secretaría de Educación Pública, México
  • The Tindall Foundation
  • University of Ouagadougou, Burkina Faso

Registry information

Official study title

A Cluster Randomised Controlled Trial (cRCT) Evaluating the Effects of Cool Roofs on Health, Environmental and Economic Outcomes in Niue

Acronym: REFLECT

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
Aug 26, 2024
Registry last updated
Feb 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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