Home Air Filtration for Traffic-Related Air Pollution (HAFTRAP)

This study is a blinded randomized crossover efficacy trial (N=172 households consisting of 207 participants) of High Efficiency Particulate Air (HEPA) filtration in near-highway homes that lack mechanical air-handling systems. Households will be randomized to 30 days of either filtration or sham filtration followed by a 30 washout period with a subsequent 30-day period of the alternative assignment. Room air filters that are commercially available will be placed in the bedroom and living room of each home.

The investigators will measure UFP and PM2.5 concentrations in 20% of the homes during filtration and sham periods and assess personal exposure in a subset of participants. The investigators will also assess chemical composition of particulate air pollution in 10 homes/year for exploratory purposes that could lead to future lines of research. The primary health endpoints will be participants' hsCRP and peripheral blood pressure, measures that the investigators have used in multiple observational studies of UFP as well as in pilot filtration intervention studies. Secondary biological measures that contribute to understanding biological pathways will be IL-6 (inflammation), D-dimer (coagulation), metabolome, central pressure and arterial stiffness. The primary intention to treat analysis will compare outcomes between HEPA filtration to sham filtration. The investigators will have 80% power to detect a difference of 0.6 mg/L in change in hsCRP and a difference in reduction in systolic blood pressure of 3.5 mmHg compared to participants who receive no filtration. Having participants serve as their own controls in the within-subject comparisons of intervention effectiveness increases statistical power and eliminates the possibility of baseline imbalances in demographic and clinical characteristics. A social science evaluation will inform final adjustments to the investigators' approach at the start and also assess participant acceptance and experience with the intervention at the end. The investigators' primary innovation is that this will be the first near highway HEPA intervention trial that is large enough and careful enough to be policy-relevant.

Study Overview

• Status: Recruiting
• Conditions: Blood Pressure; Cardiovascular Risk Factor
• Intervention / Treatment: Other: HEPA Air Filtration; Other: Sham HEPA Air Filtration

Detailed Description

Specific Aims:

Specific Aim 1: To test the effect of HEPA filtration on markers of cardiovascular risk for adults who live near urban highways. 207 participants will be enrolled in a double blind, randomized crossover trial of 30-day periods with and without filtration separated by a 30-day wash out period. The intervention will be during colder months (Oct-Mar) when ambient UFP are elevated and windows tend to be closed, thereby allowing for maximization of the exposure contrast between HEPA and sham conditions. The investigators hypothesize that the HEPA filtration intervention will be associated with indications of improved health in the primary health outcomes: blood pressure (systolic, diastolic, and pulse pressure); and hsCRP (a measure of inflammation).

Specific Aim 2: To assess whether the intervention succeeded or failed in participant homes. To determine effectiveness of the filtration intervention, the investigators will 1) measure particle pollution levels inside and outside 20% of the homes, and 2) use quantitative surveys and open-ended questions to evaluate how participants interacted with the intervention.

Specific Aim 3: To assess biomarkers that can suggest biological pathways by which filtration affects cardiovascular risk. Study participants will be measured for IL-6 (inflammation), D-dimer (coagulation), central blood pressure, and arterial stiffness (endothelial dysfunction), which constitute key steps along the presumed biological pathways. The peripheral blood plasma of all participants will also undergo metabolome analysis to provide additional evidence of biological pathways. The investigators propose this to follow on an exciting recent study that used a similar approach 24, and preliminary metabolome analysis.

Exploratory Aims: To analyze particle composition. In a subset of homes (30 homes total, 10/year), the investigators will perform detailed physical and chemical analysis of PM1 (particles <1,000 nm) to inform future work on composition-dependent health impacts and filtration effectiveness for UFP. Also in a subset of homes, assess personal exposures for 24 participants. The scientific premise is that HEPA filtration in homes without mechanical ventilation systems can reduce UFP (and overall PM) levels leading to positive changes in biomarkers. The study design and approach are rigorous, using a double blind, randomized cross over trial. The investigators will also measure objective biomarkers of risk of cardiovascular disease. The primary innovation is that this will be the first HEPA intervention trial near highways that is large enough to rule in or out efficacy of stand-alone HEPA filters from traffic pollution

Hypotheses:

1. For Aim 1, the investigators hypothesize that the HEPA filtration intervention will be associated with statistically significant improvements of peripheral blood pressure (BP) and C-reactive protein (hsCRP).
2. The investigators hypothesize that measures collected for Aim 3 will show that UFP is associated with antioxidant pathways, in vivo generation of reactive oxygen species, and processes critical to endothelial functions, as well as indicators of early vascular aging.

• Study Type: Interventional
• Enrollment (Estimated): 210
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Doug Brugge, PhD; Phone Number: (617) 636-0236; Email: doug.brugge@gmail.com

Study Locations

• United States
  • Connecticut
    • Farmington, Connecticut, United States, 06032
      • Recruiting
      • UConn Health
      • Contact: Doug Brugge, PhD; Phone Number: 860-679-8814; Email: doug.brugge@gmail.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• residence within 200 m of interstate I-93 in Somerville
• live at home full time
• cognitive ability to answer questionnaires
• able to speak English/Spanish

Exclusion Criteria:

• in-home mechanical air handling system with forced air pushed through vents
• smoker or lives with smoker(s)
• history of heart attack, stroke, or other major cardiovascular outcome
• taking anti-hypertensive or anti-inflammation medications
• occupational or other routine high exposures (away from home) to traffic pollution
• extensive use of candles/incense inside the home

Preferred Criteria:

• residents of apartments with highway-facing windows and that are no more than 3 stories tall

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: HEPA Filtration	Other: HEPA Air Filtration; 2 HEPA air filters placed in home (one in bedroom, one in living room) for 30 days
Sham Comparator: Sham HEPA Filtration	Other: Sham HEPA Air Filtration; 2 HEPA air filter devices with filter removed placed in home (one in bedroom, one in living room) for 30 days

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Systolic Blood Pressure at 1 Month	Seated blood pressure measured using ambulatory monitors	measured at study onset and 30 days
Change in High Sensitivity C-Reactive Protein (hsCRP) at 1 Month	inflammation marker assayed from blood samples	blood sample taken at study onset and 30 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in D-dimer at 1 Month	coagulation marker assayed from blood samples	blood sample taken at study onset and 30 days

Collaborators and Investigators

• Sponsor: UConn Health
• Collaborators: Boston University; Tufts University; National Institute of Environmental Health Sciences (NIEHS); Somerville Transportation Equity Partnership, Inc.; Welcome Project Inc; Olin College of Engineering
• Investigators: Principal Investigator: Doug Brugge, PhD, Tufts University

Study record dates

Study Major Dates

• Study Start (Actual): November 15, 2020
• Primary Completion (Estimated): May 31, 2024
• Study Completion (Estimated): May 31, 2024

Study Registration Dates

• First Submitted: September 10, 2019
• First Submitted That Met QC Criteria: February 19, 2020
• First Posted (Actual): February 21, 2020

Study Record Updates

• Last Update Posted (Estimated): June 19, 2023
• Last Update Submitted That Met QC Criteria: June 16, 2023
• Last Verified: June 1, 2023

More Information

Terms related to this study

• Keywords: Air Filtration; Ultrafine Particles (UFP); HEPA; Traffic-Related Air Pollution; In-home
• Other Study ID Numbers: 20-109-2; 1R01ES030289 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No