Assessing the Effects of Cool Roofs on Indoor Environments and Health in Colima, Mexico

NCT06834893 | Not Yet Recruiting DMC

• 2 other identifiers: 3728164226745/Z/22/Z
• Study Type: interventional
• Target: 800
• Locations: 1 country
• Sites: 1

Brief Summary

Ambient air temperatures in Mexico 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 northern zone of Mexico 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 Mexico. 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 Colima, Mexico.

Conditions

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; Blood Glucose Control; Depression; Heat-related Symptoms; Food Insecurity; Resting Heart Rate; Physician Diagnosed Heat-related Illnesses

Keywords

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

Outcome Measures

Primary Outcomes (3)

• 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 portable automated sphygmomanometers.

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

• 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.

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

• 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 Outcomes (22)

• 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.

• 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.

• Food insecurity

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

• Diet quality

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

• 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.

Study Arms (2)

Cool roof

EXPERIMENTAL

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

Other: Cool roof

No cool roof

NO INTERVENTION

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

Interventions

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.

Cool roof

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Permanent household resident.

You may not qualify if:

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

Sponsors & Collaborators

• CogniFit Limited: collaborator
• Universidad de Colima: collaborator
• Aditi Bunker: lead
• Heidelberg University: collaborator
• Rutgers University: collaborator
• Boston University: collaborator
• EPS: collaborator
• London School of Hygiene and Tropical Medicine: collaborator

Study Sites (1)

Universidad de Colima

Colima, Mexico

Location

MeSH Terms

Conditions

Depression; Personal Satisfaction; Dehydration; Sleep Initiation and Maintenance Disorders; Aggression; Psychological Well-Being; Diabetes Mellitus; Heat Stress Disorders

Condition Hierarchy (Ancestors)

Behavioral Symptoms; Behavior; Water-Electrolyte Imbalance; Metabolic Diseases; Nutritional and Metabolic Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Nervous System Diseases; Mental Disorders; Aberrant Motor Behavior in Dementia; Social Behavior; Glucose Metabolism Disorders; Endocrine System Diseases; Wounds and Injuries

Study Officials

• Collin Tukuitonga, Sir. Dr.

  University of Auckland, New Zealand

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Aditi Bunker, Dr

CONTACT

+49 6221 565344; aditi.bunker@uni-heidelberg.de

Collin Tukuitonga, Sir. Dr.

CONTACT

+6493737599; collin.tukuitonga@auckland.ac.nz

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Trial participants will be aware of the intervention to which they have been allocated, and the research fieldworkers will be aware of the intervention allocation. The trial steering committee members and trial statistician will remain blinded until the end of trial period and data collection.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Co-principal investigator

Study Record Dates

• First Submitted: February 13, 2025
• First Posted: February 19, 2025
• Study Start: April 1, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: March 12, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: At the time of publication.

Locations

ME (1)