Assessing the Effects of Cool Roofs on Indoor Environments and Health

Condition(s) studied

Investigational drug(s) / intervention(s)

Cool 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).

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.

Eligibility

Primary outcome measure(s)

• 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.
• 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). Minimum score of 0 and a maximum score of 27 with a higher score meaning a worse outcome.

Trial sites (5)

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