Assessing the Effects of Cool Roofs on Mental Health in Ahmedabad, India (REFLECT)

A Cluster Randomised Controlled Trial (cRCT) Evaluating the Effects of Cool Roofs on Mental Health Outcomes in Ahmedabad, India

Ambient air temperatures in India have broken record highs. 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 are susceptible to increased heat exposure.

Heat exposure can instigate and worsen mental health. 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 mental 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. To meet this goal, the investigators will conduct a cluster-randomized controlled trial to establish the effects of cool roof use on mental health in Ahmedabad, India.

Study Overview

• Status: Active, not recruiting
• Conditions: Anxiety; Resilience; PTSD - Post Traumatic Stress Disorder; Eco-anxiety
• Intervention / Treatment: Other: Cool roof

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 mental health conditions, including depression, anxiety and aggression. 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.

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 mental health outcomes in Ahmedabad.

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

• Study Type: Interventional
• Enrollment (Estimated): 800
• Phase: Not Applicable

Contacts and Locations

Study Locations

• India
  • Ahmedabad, India
    • IndianI Institute of Public Health Gandhinagar

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Permanent household resident.

Exclusion Criteria:

• Roof damage, inaccessible or instability of roof adversely affecting cool roof coating application.
• Participant unable to provide written/verbal informed consent.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cool roof; Households will receive sunlight reflecting 'cool roof' coating on their roofs.	Other: Cool roof; 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.
No Intervention: No cool roof; No cool roof application. Households will keep their original roofing for the duration of the trial.

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Aggression	Self-reported personal aggresion assessed using the Buss-Perry Aggression Questionnaire-Ultra Short Form (BPAQ-ML).	Eight measurements: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
Mental Well-being	Self-reported mental wellbeing over the last two weeks using the Short Warwick-Edinburgh Mental Well-being Scale (SWEMWBS) with a minimum score of 14 and a maximum score of 70. A higher score indicates a higher level of mental well-being.	One measurement at the end of follow-up at 12 months post-intervention
Resilience	Self-reported resilience rating over the last month using the Connor-Davidson Resilience Scale (CD-RISC-10) with a minimum score of 0 and a maximum score of 40. Higher total scores indicate a greater ability to cope with adversity and higher resilience.	One measurement at the end of follow-up at 12 months post-intervention.
Eco-anxiety	Self-reported eco-anxiety over the last two weeks measured using the Hogg Eco-Anxiery Scale with a total score range from a minimum of 0 to a maximum of 52. Higher scores on the scale and its sub-dimensions indicate higher levels of eco-anxiety.	One measurement taken at the end of follow-up at 12 months post-intervention.
Post-Traumatic Stress Disorder	Self-reported symptoms of post-traumatic stress disorder using the Short PTSD Rating Interview (SPRINT) questionnaire with a potential score range from a minimum of 0 to a maximum of 32. A higher score indicates greater PTSD symptoms.	One measurement taken at the end of follow-up at 12 months post-intervention.
Anxiety	Self-reported anxiety over the last two weeks using the GAD-7 Anxiety Severity Scale with a minimum score of 0 and a maximum score of 21. Higher scores indicate greater anxiety severity.	One measurement at the end of follow-up at 12 months post-intervention.

Collaborators and Investigators

• Sponsor: Aditi Bunker
• Collaborators: Boston University; Heidelberg University; Rutgers University; University of Auckland, New Zealand; Indian Institute of Public Health, India; Sika
• Investigators: Principal Investigator: Collin Tukuitonga, University of Auckland, New Zealand

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2024
• Primary Completion (Estimated): March 1, 2026
• Study Completion (Estimated): March 1, 2026

Study Registration Dates

• First Submitted: November 13, 2025
• First Submitted That Met QC Criteria: November 18, 2025
• First Posted (Actual): November 26, 2025

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 25, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Mental health; Housing; Heat stress; Hot temperature; Humidity; Cool roof
• Additional Relevant MeSH Terms: Trauma and Stressor Related Disorders; Mental Disorders; Wounds and Injuries; Stress Disorders, Traumatic; Behavior; Personal Satisfaction; Anxiety Disorders; Heat Stress Disorders; Combat Disorders; Psychological Well-Being
• Other Study ID Numbers: 3728166; 226745/Z/22/Z (Other Grant/Funding Number: Wellcome Trust UK)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

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.

• IPD Sharing Time Frame: At the time of publication.
• IPD Sharing Supporting Information Type: ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No