Reducing Traffic Pollution Exposure Improves Blood Pressure

NCT ID: NCT04029129

Last Updated: 2023-09-28

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 77 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2018-03-01
• Study Completion Date: 2018-06-15

Brief Summary

This randomized trial assessed the effect of modifying building envelop and level of air filtration on blood pressure over two hour exposure sessions.

Detailed Description

Living close to major roadways is associated with elevated blood pressure (BP) amongst other adverse health effects. There is growing evidence that ultrafine particles (UFP, <100 nm in diameter), which are elevated near major roads and highways, contribute to such risks. We assessed the efficacy of high efficiency particulate arrestance (HEPA) filtration and building envelope adjustment at reducing exposure to and health effects of air pollution next to major highways.

We used a randomized three-period crossover trial design to assign 77 participants (aged 40-75 and without diagnosis of hypertension) to three two-hour exposure sessions. Sessions were conducted in one of two rooms immediately adjacent to highways. High, medium and low exposures were attained by varying the degree of air exchange and amount of HEPA filtration in the room. During high exposure sessions, the room was ventilated with outdoor air and no filtration was used. During low exposure sessions, leakage of outdoor air into the room was minimized and HEPA filtration was maximized. During medium exposure sessions, a moderate amount of HEPA filtration was used (less than half of that used in low sessions). Indoor particle number and black carbon (BC) concentrations (i.e., markers of traffic-related air pollution) were monitored continuously.

During each session participants sat quietly and wore noise-cancelling headphones, while their BP was monitored every ten minutes using an ambulatory BP monitor. We monitored pulse and oxygen saturation continuously.

Conditions

Air Pollution

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: OTHER
• Blinding Strategy: SINGLE

Study Groups

High exposure

Ambient air was allowed freely into the room.

Group Type: EXPERIMENTAL

Air filtration and building envelop modifications

Intervention Type: OTHER

Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour.

Medium exposure

Limited air filtration was used to partially reduce levels of pollution in the room relative to outside.

Group Type: EXPERIMENTAL

Air filtration and building envelop modifications

Intervention Type: OTHER

Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour.

Low exposure

Doors and windows were closed and sealed and full filtration was used to maximally reduce pollution in the room.

Group Type: EXPERIMENTAL

Air filtration and building envelop modifications

Intervention Type: OTHER

Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour.

Interventions

Air filtration and building envelop modifications

Air filters and closing and sealing of windows and doors was used to reduce infiltration of air pollution from outdoors in rooms next to major highways at rush hour.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• The inclusion criterion was age 40-75 years.
• There was a preference for people who were otherwise healthy, but overweight or obese.

Exclusion Criteria

• A history of a major cardiovascular outcome (including myocardial ischemia (MI), stroke, angina)
• Other serious health problems (current asthma or COPD)
• Taking anti-hypertensive medications
• Smoking or living with a smoker
• Cognitive impairment
• Working at a job with high combustion exposure (taxi/truck driver, restaurant cook)
• High combustion exposure in the preceding 24 hours (driving on the highway, cooking in a restaurant, driving a truck)
• Not speaking English or Chinese.

• Minimum Eligible Age: 40 Years
• Maximum Eligible Age: 75 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

National Institute of Environmental Health Sciences (NIEHS)

NIH

Sponsor Role: collaborator

UConn Health

OTHER

Sponsor Role: lead

Responsible Party

Douglas Brugge

Professor and Chair

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

University of Connecticut

Farmington, Connecticut, United States

Countries

United States

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Document Type: Informed Consent Form

View Document

Other Identifiers

R01ES026980

Identifier Type: NIH

Identifier Source: secondary_id

View Link

19X-183=1

Identifier Type: -

Identifier Source: org_study_id