NCT01508637

Brief Summary

Double-blind, sham- and placebo-controlled randomized study of effects of freshly-generated diluted diesel exhaust inhalation on vascular function. To examine role of adrenergic system a trial of alpha-blocker terazosin is also used. Each participant completes four study sessions, separated by at least three weeks: 1) Diesel exhaust inhalation (DE, controlled at 300 micrograms/cubic meter for two hours) and terazosin (2 mg prior to inhalation exposure); 2) DE plus placebo (matched for terazosin); 3) filtered air plus terazosin; and 4) filter air plus placebo. The investigators assess outcomes of blood pressure, forearm brachial artery ultrasound, and plasma measures of endothelial activation. The investigators hypothesize that DE exposure will be associated with increased blood pressure, decreased brachial artery diameter, and increased circulating endothelins, and that these effects will be attenuated by terazosin administration.

Trial Health

43
At Risk

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Trial has exceeded expected completion date
Enrollment
24

participants targeted

Target at below P25 for not_applicable

Timeline
Completed

Started Jan 2012

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
unknown

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Start

First participant enrolled

January 1, 2012

Completed
4 days until next milestone

First Submitted

Initial submission to the registry

January 5, 2012

Completed
7 days until next milestone

First Posted

Study publicly available on registry

January 12, 2012

Completed
3.9 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 1, 2015

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 1, 2015

Completed
Last Updated

August 3, 2015

Status Verified

July 1, 2015

Enrollment Period

3.9 years

First QC Date

January 5, 2012

Last Update Submit

July 30, 2015

Conditions

Cardiovascular Effects

Keywords

air pollutionvasoconstrictionblood pressurediesel exhaust

Outcome Measures

Primary Outcomes (1)

  • Systolic Blood Pressure

    30-90 minutes after exposure initiation

Secondary Outcomes (1)

  • Brachial artery diameter

    Assessed 30 minutes prior to exposure and 30 minutes post-exposure

Study Arms (4)

Diesel Exhaust + Terazosin

EXPERIMENTAL
Other: Diesel ExhaustDrug: Terazosin

Diesel Exhaust + placebo

EXPERIMENTAL
Other: Diesel ExhaustDrug: placebo

Filtered Air + terazosin

SHAM COMPARATOR
Other: Filtered AirDrug: Terazosin

Filtered air + placebo

SHAM COMPARATOR
Other: Filtered AirDrug: placebo

Interventions

Diesel ExhaustOTHER

Freshly generated diesel exhaust, diluted to 300 micrograms/cubic meter. Exposures are two hours in duration.

Diesel Exhaust + TerazosinDiesel Exhaust + placebo
Filtered AirOTHER

Sham exposure, identical to conditions of diesel exhaust exposure, but with only air filtered of particles and volatile organic compound gases

Filtered Air + terazosinFiltered air + placebo
TerazosinDRUG

2 mg by mouth, 90 minutes prior to exposure initiation

Diesel Exhaust + TerazosinFiltered Air + terazosin
placeboDRUG

capsule, identical in appearance to terazosin capsule, by mouth, 30 minutes prior to exposure initiation

Diesel Exhaust + placeboFiltered air + placebo

Eligibility Criteria

Age18 Years - 49 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64)

You may qualify if:

  • healthy without chronic illness
  • Body Mass Index 18.5 - 26.0
  • tolerates 2 mg terazosin dose without unacceptable symptoms
  • able to return for four exposure sessions

You may not qualify if:

  • any chronic disease
  • tobacco user
  • asthma
  • elevated cholesterol
  • obesity
  • hypertension
  • diabetes
  • any chronic cardiovascular or pulmonary disease
  • pregnancy or unwillingness to use effective contraception, if female

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

University of Washington Medical Center

Seattle, Washington, 98195, United States

RECRUITING

MeSH Terms

Interventions

Vehicle EmissionsTerazosin

Intervention Hierarchy (Ancestors)

Complex Mixtures

Study Officials

  • Joel D Kaufman, MD, MPH

    University of Washington

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Karen Jansen, M.S.

CONTACT

206-616-6525cvd1trap@uw.edu

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
TRIPLE
Who Masked
PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
Purpose
PREVENTION
Intervention Model
CROSSOVER
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Professor

Study Record Dates

First Submitted

January 5, 2012

First Posted

January 12, 2012

Study Start

January 1, 2012

Primary Completion

December 1, 2015

Study Completion

December 1, 2015

Last Updated

August 3, 2015

Record last verified: 2015-07

Locations

US(1)