Air PollutionNCT05718245
HEPA, PM2.5, and Cardiometabolic Health
A study testing HEPA filter in people with Air Pollution and Cardiometabolic Health, run by University of Southern California at 1 site in United States.
Trial summary
The goal of this randomized, double-blind, crossover trial is to test the hypothesis that a longer-term indoor HEPA filtration intervention can improve cardiometabolic profiles by reducing indoor PM2.5 exposures in at-risk individuals. Read more about this study
- Who is it for?
- Ages 65 to 84 yearsHealthy volunteers can take part
- Conditions the study is for
- Air Pollution, Cardiometabolic Health
- What is being tested?
- HEPA filter
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 52 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Mar 2023to 31 Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 65 to 84 years
- All sexes
- Healthy volunteers accepted
- Older adult
Who may be able to join
- Age between 65 and 84 years old;
- Nonsmoker for at least 1 year;
- History of BMI ≥ 25 kg/m2 in the past based on EMR information;
- Either an English or Spanish speaker;
- Live in the Los Angeles County.
Who cannot join
- History of diabetes (both type 1 and type 2) or degenerative disease of the nervous system (Alzheimer's disease or dementia);
- Currently have active cancer treatment;
- The residential house has already had HEPA filters;
- Participants will move out of the current house in the next 2 years;
- Participants will spend more than one month living outside the primary home;
- Have any health conditions that prohibit collecting health and covariate data and biospecimen;
- The residential houses are not feasible for setting up air purifiers and air pollutants monitors;
- Have high blood glucose from finger stick test (> 200 mg/dL).
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Keck School of Medicine, University of Southern California
Los Angeles, California, 90033
Zhanghua Chen, PhD, 323-442-2109, zhanghuc@usc.edu
About this study
Official title: Using Indoor Air Filtration to Reduce PM2.5 Cardiometabolic Effects in At-risk Individuals
The goal of this randomized, double-blind, crossover trial is to test the hypothesis that a longer-term indoor HEPA filtration intervention can improve cardiometabolic profiles by reducing indoor PM2.5 exposures in at-risk individuals.
Read the detailed description
This randomized, double-blind, crossover trial will recruit 52 non-diabetic adults and will investigate potential benefits of HEPA air purifiers on improving cardiometabolic profiles. Participants will be contacted and recruited to the study based on inclusion and exclusion criteria. After consenting, participants will be block randomized to HEPA and control groups for 6-month interventions by sex. After 6-month wash-out period, participants will be switched to the other arm of the intervention. During the trial, project specialists will complete a series of home visits before and after each intervention session to set up air purifiers and indoor and outdoor air pollution monitors, as well as conduct interview to collect questionnaire data, measure body weight and blood pressure, and collect biospecimen. In aim 1, the researcher will assess the effect of a 6-month residential HEPA intervention on changes of type 2 diabetes-related metabolic outcomes in 52 adults. In aim 2, the researchers will examine the association between reduction in indoor PM2.5 exposure brought by the intervention and changes in metabolic outcomes adjusting for ambient PM2.5 exposure. In aim 3, the researchers will explore major pathophysiologic changes pertinent to the cardio-metabolic profile of type 2 diabetes relevance in response to the intervention and changes in PM2.5 exposure.
- Conditions
- Air Pollution, Cardiometabolic Health
- Being tested
- HEPA filter, Sham filter
- Keywords
- Air pollution, Particulate matter, Air purifier, HEPA filter, Cardiometabolic health
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
HEPA filterDevice
HEPA filters with the capacity to reduce PM2.5 levels
Sham filterDevice
sham filters without the capacity to reduce PM2.5 levels
| Study group | Role | What they receive |
|---|---|---|
| HEPA first and sham | Experimental | This group of participants will be assigned an intervention of HEPA filters with the capacity to reduce PM2.5 levels at their residence for 6 months. After 6-month wash-out period, will be assigned to sham filters for 6 months. Receives: Device: HEPA filter; Device: Sham filter |
| Sham first and HEPA | Sham comparator | This group of participants will be assigned an intervention of sham filters without the capacity to reduce PM2.5 levels at their residence for 6 months. After 6-month wash-out period, will be assigned to HEPA filters for 6 months. Receives: Device: HEPA filter; Device: Sham filter |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in HOMA-IR
Difference between baseline and HOMA-IR measured after 6-month intervention
Measured: At the baseline and immediately after each of the 6-month interventions
Change in HbA1c
Difference between baseline and HOMA-IR measured after 6-month intervention
Measured: At the baseline and immediately after each of the 6-month interventions
Secondary outcomes (5)
Change in fasting glucose
Difference between baseline and fasting glucose measured after 6-month intervention
Measured: At the baseline and immediately after each of the 6-month interventions
Change in fasting insulin
Difference between baseline and fasting insulin measured after 6-month intervention
Measured: At the baseline and immediately after each of the 6-month interventions
Changes in lipid profiles
Differences between baseline and LDL, HDL, VLDL, triglycerides, and total cholesterol levels measured after 6-month intervention
Measured: At the baseline and immediately after each of the 6-month interventions
Change in blood pressure
Differences between baseline and systolic and diastolic blood pressure measured after 6-month intervention
Measured: At the baseline and immediately after each of the 6-month interventions
Change in continuously monitored glucose level
Difference in continuously measured glucose measured using Abbott FreeStyle Libre 2 Pro Continuous Glucose Monitor (CGM) for 2 weeks between baseline and after intervention.
Measured: At the baseline and immediately after 3 months of intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Feb 2023
- Study start15 Mar 2023
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Air PollutionStudies of the same condition, open and under way.
- More trials run by University of Southern CaliforniaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 52 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Southern California
- Sponsor type
- University, hospital or other
- Collaborators
- Duke University
- Responsible party
- Principal investigator, Zhanghua Chen, University of Southern California
- Investigators
- Zhanghua Chen, PhD, Principal investigator, University of Southern CaliforniaJunfeng Zhang, PhD, Principal investigator, Duke University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05718245
- Sponsor's protocol ID
- UL2_Study
- Status last verified
- Jul 2025
- First submitted
- 24 Jan 2023
- Last updated
- 1 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 1 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Using Indoor Air Filtration to Reduce PM2.5 Cardiometabolic Effects in At-risk Individuals
- ClinicalTrials.gov ID
- NCT05718245
- Acronym / sponsor ID
- UL2_Study
- Conditions
- Air Pollution, Cardiometabolic Health
- Keywords
- Air pollution, Particulate matter, Air purifier, HEPA filter, Cardiometabolic health
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 52 participants (estimated)
- Lead sponsor
- University of Southern CaliforniaUniversity, hospital or other
- Collaborators
- Duke University
- Study start
- 15 Mar 2023 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 8 Feb 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this randomized, double-blind, crossover trial is to test the hypothesis that a longer-term indoor HEPA filtration intervention can improve cardiometabolic profiles by reducing indoor PM2.5 exposures in at-risk individuals.
Detailed description
This randomized, double-blind, crossover trial will recruit 52 non-diabetic adults and will investigate potential benefits of HEPA air purifiers on improving cardiometabolic profiles. Participants will be contacted and recruited to the study based on inclusion and exclusion criteria. After consenting, participants will be block randomized to HEPA and control groups for 6-month interventions by sex. After 6-month wash-out period, participants will be switched to the other arm of the intervention. During the trial, project specialists will complete a series of home visits before and after each intervention session to set up air purifiers and indoor and outdoor air pollution monitors, as well as conduct interview to collect questionnaire data, measure body weight and blood pressure, and collect biospecimen. In aim 1, the researcher will assess the effect of a 6-month residential HEPA intervention on changes of type 2 diabetes-related metabolic outcomes in 52 adults. In aim 2, the researchers will examine the association between reduction in indoor PM2.5 exposure brought by the intervention and changes in metabolic outcomes adjusting for ambient PM2.5 exposure. In aim 3, the researchers will explore major pathophysiologic changes pertinent to the cardio-metabolic profile of type 2 diabetes relevance in response to the intervention and changes in PM2.5 exposure.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| HEPA first and sham | Experimental | Device: HEPA filter, Device: Sham filterThis group of participants will be assigned an intervention of HEPA filters with the capacity to reduce PM2.5 levels at their residence for 6 months. After 6-month wash-out period, will be assigned to sham filters for 6 months. |
| Sham first and HEPA | Sham comparator | Device: HEPA filter, Device: Sham filterThis group of participants will be assigned an intervention of sham filters without the capacity to reduce PM2.5 levels at their residence for 6 months. After 6-month wash-out period, will be assigned to HEPA filters for 6 months. |
Who may qualify
- Ages
- 65 to 84 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Older adult
Key inclusion criteria (5 listed)
- Age between 65 and 84 years old;
- Nonsmoker for at least 1 year;
- History of BMI ≥ 25 kg/m2 in the past based on EMR information;
- Either an English or Spanish speaker;
- Live in the Los Angeles County.
Key exclusion criteria (8 listed)
- History of diabetes (both type 1 and type 2) or degenerative disease of the nervous system (Alzheimer's disease or dementia);
- Currently have active cancer treatment;
- The residential house has already had HEPA filters;
- Participants will move out of the current house in the next 2 years;
- Participants will spend more than one month living outside the primary home;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| HEPA filterHEPA filters with the capacity to reduce PM2.5 levels | Device | HEPA first and sham, Sham first and HEPA |
| Sham filtersham filters without the capacity to reduce PM2.5 levels | Device | HEPA first and sham, Sham first and HEPA |
Primary outcome
Change in HOMA-IR
Time frame: At the baseline and immediately after each of the 6-month interventions
Difference between baseline and HOMA-IR measured after 6-month intervention
Change in HbA1c
Time frame: At the baseline and immediately after each of the 6-month interventions
Difference between baseline and HOMA-IR measured after 6-month intervention
5 secondary outcomes
Change in fasting glucose
Time frame: At the baseline and immediately after each of the 6-month interventions
Change in fasting insulin
Time frame: At the baseline and immediately after each of the 6-month interventions
Changes in lipid profiles
Time frame: At the baseline and immediately after each of the 6-month interventions
Change in blood pressure
Time frame: At the baseline and immediately after each of the 6-month interventions
Change in continuously monitored glucose level
Time frame: At the baseline and immediately after 3 months of intervention
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Aug 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Zhanghua Chen, PhD principal investigator
University of Southern California
Junfeng Zhang, PhD principal investigator
Duke University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing HEPA filter in people with Air Pollution and Cardiometabolic Health, run by University of Southern California at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 1 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Zhanghua Chen, PhD (323-442-2109, zhanghuc@usc.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in HOMA-IR (time frame: At the baseline and immediately after each of the 6-month interventions). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Aug 2025.