Clinical trial NCT06834893: Assessing the Effects of Cool Roofs on Indoor Environments and Health in Hermosillo, Mexico
Official title: A Cluster Randomised Controlled Trial (cRCT) Evaluating the Effects of Cool Roofs on Health, Environmental and Economic Outcomes in Hermosillo, Mexico
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: NA
Conditions: Resting Heart Rate
Blood Glucose Control
Depression
Heat-related Symptoms
Physician Diagnosed Heat-related Illnesses
Food Insecurity
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
Keywords: Hot Temperature
Humidity
Housing
Heart rate
Cardiovascular
Depression
Mental health
Blood glucose
Diabetes
Cool roof
Heat Stress
Lead sponsor: University of Auckland, New Zealand
Sponsor class: OTHER
Collaborators: name: Heidelberg University
name: Rutgers University
name: Boston University
name: Secretaría de Educación Pública, México
name: CogniFit Limited
name: EPS
name: London School of Hygiene and Tropical Medicine
First posted: 2025-02-19
Enrollment: 800
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: Ambient air temperatures in Mexico have broken record highs in 2024 with Hermosillo reaching the highest maximum temperature recorded in Mexico at 51.9 C. 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 northern zone of 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 Hermosillo, Mexico.

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.

Cities and towns of LMIC 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 Hermosillo (located in the State of Sonora, Mexico) are exposed to heat and low humidity year-round. The State of Sonora has a large burden of non-communicable diseases (NCDs), with nearly 28% of deaths due to NCDs, such as heart diseases and diabetes mellitus. The combined burden of heat and NCDs places Sonora's, especially Hermosillo's, 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 Hermosillo.

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

Eligibility criteria: 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.

Primary outcomes:
measure: Resting heart rate
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Blood glucose control
timeFrame: Two measurements will be taken: one at baseline and one in the last month of three consecutive hottest months.
measure: Depression
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
Secondary outcomes:
measure: Heat-related symptoms
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Physician diagnosed heat-related illnesses
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Food insecurity
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Diet quality
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Health-related quality of life
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Indoor thermal comfort
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Coping ability
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Life satisfaction
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Healthcare provider utilization
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Hospitalization
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Systolic Blood Pressure
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.
measure: Diastolic Blood Pressure
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.
measure: Cognition
timeFrame: Eight measurements: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Inner Ear Canal Temperature
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.
measure: Dehydration
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Sleep quality
timeFrame: Eight measurements: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Aggression
timeFrame: Eight measurements: one at baseline and seven over 12 months, covering three consecutive hottest months and four alternate months.
measure: Productivity
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.
measure: Indoor air temperature
timeFrame: Measurements at 15 minute intervals for 12 months.
measure: Indoor relative humidity
timeFrame: Measurements at 15 minute intervals for 12 months.
measure: Indoor heat index
timeFrame: Measurements at 15 minute intervals for 12 months.
measure: Household energy expenditure
timeFrame: Eight measurements will be taken: one at baseline and seven over 12 months, covering the three consecutive hottest months and four alternate months.
Other outcomes:
Locations:
city: Hermosillo
country: Mexico
facility: Instituto Tecnológico de Hermosillo
state: Sonora
Study officials:
affiliation: University of Auckland, New Zealand
name: Collin Tukuitonga, Sir. Dr.
role: PRINCIPAL_INVESTIGATOR
References: