Clinical trial NCT06982339: Beat the Heat Boston
Official title: Beat the Heat: Impacts of Heat on Health in Boston and Strategies to Address Them
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: NA
Conditions: Hot Weather; Adverse Effect
Heat Effect
Heat Stress
Heat Stroke, Heat Exhaustion
Heat Exposure
Heat Strain
Keywords: Cooling
Air conditioner
Heat related illness
stepped wedge
Lead sponsor: Harvard School of Public Health (HSPH)
Sponsor class: OTHER
Collaborators: name: Fogarty International Center of the National Institute of Health
First posted: 2025-05-21
Enrollment: 100
Sex: ALL
Minimum age (years): 55
Maximum age (years): 95
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: This study follows a stepped wedge randomized controlled trial (SW-RCT) design to evaluate the health and environmental impacts of air conditioning among older adults with chronic health conditions. A total of 100 participants are randomized into two groups:

Arm A (Early AC Group): Receives a window AC unit in Year 1, along with a financial subsidy for electricity..

Arm B (Delayed AC Group): Receives an identical AC unit in Year 2, along with a financial subsidy for electricity.

In Year 1, participants in Arm A (AC) are compared to those in Arm B (no AC) to assess the direct effect of AC access.

In Year 2, both arms have AC units, but only Arm B receives the electricity subsidy, allowing evaluation of cost as a barrier to use.
Primary purpose: PREVENTION

Brief summary: The goal of this stepped wedge trial is to assess the practical effects of air conditioners on hot weather impacts among older adults. The main questions it aims to answer are:

How does the presence of an air conditioning unit affect heat stress, heat strain, mental health, and healthcare utilization among older adults who did not previously have access to air conditioning?

How, and in what conditioners, do older adults use air conditioning once it is installed in their home?

Researchers will compare participants in arms with (A) and without (B) air conditioning units in the first summer season; this will allow them to assess the effect of air conditioners. In the second summer season, both arms will have air conditioning units, but those in the year two distribution arm (B) will receive an electricity subsidy, while those in the year one AC distribution arm (A) will not, allowing researchers to assess the effect of an electricity subsidy.

Participants will be randomized to receive an air conditioner and financial support for electricity costs in either the first summer season or the second summer season of the study.

* Heat stress, heat strain, mental health, and healthcare utilization will be assessed via participant survey.
* Air conditioner utilization will be assessed via continuous load monitoring devices.
* Indoor air temperature will be assessed via continuous data loggers.

Detailed description: This community-based, randomized stepped wedge trial investigates whether the provision of educational resources and air conditioning (AC) improves thermal comfort and health outcomes among older adults with chronic disease and material hardships. The study will enroll 100 participants residing in at risk neighborhoods. Eligibility criteria include adults aged 55-95 who speak English or Spanish, lack access to home cooling systems, and have at least one qualifying chronic health condition or a history of recent hospitalization (see Eligibility section) .

Participants will be randomly assigned (1:1) to receive window AC units and an electricity cost subsidy either in Year 1 or Year 2. All participants in both arms will receive a baseline intervention including heat health educational materials and cooling kits. Data collection will occur over two warm seasons (April-September) and involve pre- and post-intervention assessments using structured surveys, real-time environmental monitoring, and AC usage tracking.

Surveys administered at enrollment and in late summer each year will capture a broad range of covariates including sociodemographic data, housing conditions, health service utilization, self-reported symptoms, and adaptive behaviors. Heat stress, heat strain, mental health, and healthcare utilization outcomes will be assessed via surveys that include previously validated survey instruments. Specific emphasis will be placed on measures of energy insecurity, such as utility shutoff notices, receipt of energy assistance, and trade-offs between essential expenses. Environmental sensors will log indoor temperature, humidity, and pollutant data throughout the study period.

The primary outcome is self-reported health status as measured by a modified ESQ-IV, supplemented by secondary metrics including ASHRAE thermal comfort scores, POMS, emergency department presentations, and hospitalizations. Statistical analysis will employ two-sample t-tests to detect treatment effects, with a minimum detectable effect size of 5.66 assuming a standard deviation of 10 and balanced sample sizes.

This study aims to empirically quantify the health benefits of cooling interventions in high-risk older adults and inform scalable public health strategies that address the intersecting challenges of urban heat, climate change, chronic disease management, and housing-related inequities.

Eligibility criteria: Inclusion Criteria:

* reside in Roxbury, Dorchester, East Boston or Mattapan MA
* age 55-95 years old
* speak English or Spanish
* do not have air conditioning in the home
* living with at least one of the following conditions: chronic CVD (hypertension, hyperlipidemia, diabetes, history of stroke or myocardial infarction, atrial fibrillation, or heart failure), chronic pulmonary disease (asthma, COPD/emphysema, interstitial lung disease), chronic neurologic disease (stroke, Parkinson's disease, or other chronic neurologic conditions), chronic mental health conditions (including anxiety disorder, major depression, bipolar disorder), and/or history of hospitalization (defined as spending at least one night in the hospital) for any reason within the past three years.

Exclusion Criteria:

- Lack a location in their home suitable for installation of the AC unit provided during the research study.

Primary outcomes:
measure: Environmental Symptoms Questionnaire (ESQ-IV)
timeFrame: Difference in self-reported symptoms on HSSQ administered in the late summer season, 2-12 weeks after enrollment.
Secondary outcomes:
measure: Air Conditioner Utilization
timeFrame: From enrollment to study completion, approximately 2 years.
Other outcomes:
Locations:
Study officials:
affiliation: Harvard School of Public Health (HSPH)
name: Gary Adamkiewicz Associate Professor of Environmental Health and Exposure Disp., PhD, MPH, MS
role: PRINCIPAL_INVESTIGATOR
References: