Recruiting

Indoor Air Filtration

Sponsor:

University of Southern California

Code:

NCT05867381

Conditions

Air Pollution

Atherosclerosis

Eligibility Criteria

Sex: All

Age: 65 - 70+

Healthy Volunteers: Not accepted

Interventions

HEPA filtration

Sham filtration

Study Details

Brief summary:

This double-blind, randomized, crossover trial aims to test the hypothesis that longer-term indoor air filtration intervention can slow atherothrombosis progression by reducing indoor fine particulate matter (PM2.5) exposure in adults with ischemic heart disease history.

Conditions

Air Pollution

Atherosclerosis

Study ID

NCT05867381

Start date

Jul 11, 2023

Status verified date

Jun, 2026

Completion date

Jun 30, 2028

Anticipated

Primary completion date

Jun 30, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 65 - 70+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Age between 65 and 84 years old;
  • Weight ≥ 110 pounds;
  • Nonsmokers for at least 1 year;
  • Have ischemic heart disease history, clinically stable for 6 months, without any deterioration in symptoms or episodes of angina based on past electronic medical records;
  • Both English and Spanish speaking participants will be included in the recruitment;
  • Live in the Los Angeles County.

Exclusion Criteria:

  • Have history of degenerative disease of the nervous system such as dementia and Alzheimer's;
  • Currently have active cancer treatments;
  • The residential house has already had HEPA filters;
  • Participants will move out from the current residential address in the next 2 years;
  • Participants will spend more than 1 month living outside the primary home;
  • Have any health conditions that prohibit collecting health and covariate data and biospecimens;
  • Participants' residential houses are not feasible for setting up air purifiers and air pollutants monitors.

Study Design

Enrollment

112 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Prevention

Interventions and Outcome Measures

Arms

experimental: HEPA first and sham

This group of participants will be assigned to the intervention of HEPA filtration with the capacity to reduce indoor PM2.5 levels at their residence for 9 months first. After 3-month wash-out period, participants will be assigned to sham filters (air purifier has the same appearance but HEPA filter is removed) for 9 months.

experimental: Sham first and HEPA

This group of participants will be assigned to the intervention of sham filtration with HEPA filter removed at their residence for 9 months first. After 3-month wash-out period, participants will be assigned to the HEPA filtration for 9 months.

Interventions

HEPA filtration

HEPA filters with the capacity to reduce PM2.5 levels

Sham filtration

Sham filtration use the same appearance of air purifier but with HEPA filter removed.

Primary outcome measure

  • Change in blood pressure [ Time Frame: Blood pressure will be monitored daily during each of the 9-month intervention ]
  • Change in carotid-femoral pulse wave velocity [ Time Frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions ]
  • Change in augmentation index [ Time Frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions ]
  • Change in von Willebrand factor [ Time Frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions ]
  • Change in P-selectin [ Time Frame: At the baseline, in the middle (4.5 month after intervention) and immediately after each of the 9-month interventions ]

Central Contacts and Locations

Central contacts

Zhanghua Chen, PhD

323-442-2109zhanghuc@usc.edu

Junfeng Zhang, PhD

919-681-7782junfeng.zhang@duke.edu

Locations

Keck School of Medicine, University of Southern California

Recruiting

Los Angeles, California, United States, 90033

Contacts

Zhanghua Chen, PhD

323-442-2109zhanghuc@usc.edu

More Information

Sponsor

University of Southern California

Last update posted

Jun 8, 2026

Last verified

Jun, 2026

Keywords

  • Air pollution
  • Particulate matter
  • Air purifier
  • HEPA filter
  • Atherosclerosis
  • Ischemic Heart Disease
  • Thrombosis
  • Cardiovascular Disease

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by University of Southern California on 2026-06-08.