Effect of Commute Traffic on Vascular Function

The investigators will assess the vascular effects of riding in a car in heavily trafficked roadways, and whether filtering the car's air reduces those effects.

Study Overview

• Status: Completed
• Conditions: Cardiovascular Diseases
• Intervention / Treatment: Other: Filtered Air

Detailed Description

In this double-blind, crossover trial, randomized to order, recruited participants will be screened and then will accompany the study team on three typical commutes on separate days with sufficient washout (i.e., three weeks) between drives. One day this will occur with an effective filter system in the vehicle and the other two days without effective filtration; ineffective filtration is the most typical actual vehicle condition. Subjects will be unaware of the filtration conditions of the commute on that day. Each subject's experimental sessions will occur at the same time of day and will be separated by at least 21 days. The two sessions (either filtered air or traffic-derived entrained air) will be 120 minutes in duration and will encompass routes on heavily traveled roadways in the Seattle area. Before subjects begin the commute trials, they will go through the consent process and a series of screening tests. The study investigators will assess a series of measures regarding vascular function before and after each drive.

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Washington
    • Seattle, Washington, United States, 98195
      • University of Washington Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 49 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• healthy

Exclusion Criteria:

• asthma,
• high blood pressure,
• diabetes,
• high cholesterol,
• other chronic conditions requiring ongoing medical care.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Typical Commute; Participants spend two hours in automobile, on heavily trafficked roadways, without active filtration of air pollutants
Other: Typical Commute, Filtered Air; Participants spend two hours in automobile, on heavily trafficked roadways, with active filtration of air pollutants	Other: Filtered Air; The vehicle is fitted with a (High-Efficiency Particulate Absorbing, HEPA) filter device incorporating a charcoal filter, as well as an augmented cabin filter

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Brachial Artery Diameter from Pre-Drive to Post-Drive	Ultrasound assessment of brachial artery diameter, in millimeters.	30 minutes before 120 minute driving session; 30 minutes post driving session
Change in Blood Pressure from Pre-Drive to During-Drive and Post-drive	systolic and diastolic blood pressure measured in mmHg	10 minutes before driving session; 15, 30, 45, 60, 75, 90, 100, 120 minutes following start of (120 minute) driving session; 10 minutes, 1.5 hours, 3.5 hours, 6 hours, 24 hours after end of driving session.
Change in Retinal Arteriolar Diameter from Pre-Drive to Post-Drive	measured by retinal photography, image analysis, in micrometers	30 minutes before 120 minute driving session; 30 minutes post driving session
Gene Expression and DNA methylation	analysis in circulating mononuclear cells; determined via fold change in abundance	30 minutes before 120 minute driving session; 30 minutes, 5 hour, and 24 hours post-driving session

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
circulating stress hormone	cortisol by chemiluminescence (ng/mL)	30 minutes before 120 minute driving session; 5 hour and 24 hours post-driving session
complete blood count with differential	laboratory values for hematologic indices (cells/uL)	30 minutes before 120 minute driving session; 5 hour and 24 hours post-driving session
inflammatory marker interleukin-6	interleukin-6 determined by chemiluminescence (pg/mL)	30 minutes before 120 minute driving session; 5 hour and 24 hours post-driving session
inflammatory marker c-reactive protein	C-reactive protein by immunoturbidimetry (ug/mL)	30 minutes before 120 minute driving session; 5 hour and 24 hours post-driving session

Collaborators and Investigators

• Sponsor: University of Washington
• Collaborators: National Institute of Environmental Health Sciences (NIEHS); Environmental Protection Agency (EPA)
• Investigators: Principal Investigator: Joel Kaufman, MD, University of Washington

Study record dates

Study Major Dates

• Study Start: January 1, 2015
• Primary Completion (Actual): July 1, 2016
• Study Completion (Actual): December 1, 2016

Study Registration Dates

• First Submitted: July 31, 2015
• First Submitted That Met QC Criteria: July 8, 2022
• First Posted (Actual): July 12, 2022

Study Record Updates

• Last Update Posted (Actual): July 12, 2022
• Last Update Submitted That Met QC Criteria: July 8, 2022
• Last Verified: July 1, 2022

More Information

Terms related to this study

• Keywords: vascular function; air pollution; traffic; diesel exhaust; gasoline exhaust
• Additional Relevant MeSH Terms: Cardiovascular Diseases
• Other Study ID Numbers: STUDY00001196; K24ES013195 (U.S. NIH Grant/Contract); RD-83479601 (Other Grant/Funding Number: US Environmental Protection Agency STAR)

Drug and device information, study documents

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