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

Not Applicable

Recruiting

• Conditions: Diet Quality; Dehydration; Resting Heart Rate; Depression; Physician Diagnosed Heat-related Illnesses; Food Insecurity; Healthcare Provider Utilization; Systolic Blood Pressure; Sleep Quality; Cognition

• Registration Number: NCT06570993
• Lead Sponsor: Aditi Bunker

Brief Summary

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.

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 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.

Study Timeline

• Study First Submitted: 2024-08-22
• Study First Submitted QC: 2024-08-22
• Study First Posted: 2024-08-26
• Study Start: 2024-09-04
• Status Verified: 2024-12
• Last Update Submitted: 2024-12-03
• Last Update Posted: 2024-12-05
• Primary Completion: 2026-01-31
• Study Completion: 2026-01-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 800

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Depression	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).
Resting heart rate	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.
Blood glucose control	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.

Secondary Outcome Measures

Name	Time	Method
Heat-related symptoms	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.
Hospitalization	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.
Systolic Blood Pressure	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.
Inner Ear Canal Temperature	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.
Food insecurity	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).
Health-related quality of life	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.
Diet quality	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).
Physician diagnosed heat-related illnesses	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.
Indoor thermal comfort	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.
Coping ability	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.
Cognition	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.
Life satisfaction	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.
Healthcare provider utilization	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.
Diastolic Blood Pressure	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.
Dehydration	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.
Aggression	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).
Productivity	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).
Household energy expenditure	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.
Sleep quality	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).
Indoor air temperature	Measurements at 15 minute intervals for 12 months.	Indoor air temperature (℃) measured using Hobo MX1101 heat and humidity measurement device.
Indoor relative humidity	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.
Indoor heat index	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.

Trial Locations

Locations (1)

University of Auckland; 🇳🇺 Auckland, Niue

University of Auckland

🇳🇺Auckland, Niue

Collin Tukuitonga, Sir. Dr.

Contact

Noah H Bunkley, Dr.

Contact

noah.bunkley@auckland.ac.nz

Noah H Bunkley, Dr

Contact

Chris Bullen, Prof. Dr.

Contact

Aditi Bunker, Dr.

Contact