Clinical trial NCT01495325: Effect of Woodsmoke on Vascular Function
Official title: Effect of Woodsmoke on Vascular Function in Healthy Firefighters
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Vascular Function
Keywords: Firefighter
Woodsmoke
Vascular function
Air Pollution
Endothelial function
Thrombosis
Lead sponsor: University of Edinburgh
Sponsor class: OTHER
Collaborators: name: Umeå University
name: NHS Lothian
First posted: 2011-12-20
Enrollment: 16
Sex: MALE
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: Exposure to air pollution is a well established risk factor for the development of heart disease. Firefighters are exposed to excess air pollution in the form of wood smoke during the extinguishing of forest or woodland fires. Heart attacks in on-duty firefighters have been linked to specific duties and in particular fire suppression, but the reasons for this increase in risk are not well understood. Exposure to wood smoke may alter blood vessel function and increase blood clot formation to explain the link between fire suppression and heart attacks.

The investigators wish to determine the effect of exposure to wood smoke at concentrations found at the perimeter of a woodland fire on blood vessel function and clotting in healthy non-smoking male professional firefighters or volunteers. Volunteers will be studied before and after inhalation of wood smoke or clean air for one hour in a purpose built whole-body exposure chamber. The investigators will perform comprehensive vascular assessments thereafter.

Understanding the effects of wood smoke on the blood vessels and clotting will be an important first step in helping to protect firefighters from heart disease. Through research, the investigators hope to identify methods to minimise the risk of heart attacks in firefighters and understand the health effects of a major source of air pollution that is relevant to the general population.


Eligibility criteria: Inclusion Criteria:

* Non-smoking healthy male firefighters or volunteers

Exclusion Criteria:

* Current smoker or regular users of snus
* History of lung or ischaemic heart disease
* Malignant arrhythmia
* Systolic blood pressure \>190mmHg or \<100mmHg
* Renal or hepatic dysfunction
* Previous history of blood dyscrasia
* Unable to tolerate the supine position
* Blood donation within the last 3 months
* Recent respiratory tract infection within the past 4 weeks
* Routine medication including aspirin and NSAIDs

Primary outcomes:
measure: Forearm blood flow measured by venous occlusion plethysmography in response to infused vasodilators
timeFrame: 4-6 hours after exposure
Secondary outcomes:
measure: Ex-vivo thrombus formation using the Badimon chamber
timeFrame: 2 hours after exposure
measure: Plasma t-PA and PAI concentrations following infusion of bradykinin
timeFrame: During forearm study, 4-6hours after exposure
Other outcomes:
Locations:
city: Umeå
country: Sweden
facility: Umeå University
state: Västerbotten
Study officials:
affiliation: University of Edinburgh
name: Nicholas L Mills, MBChB PhD
role: STUDY_DIRECTOR
affiliation: University of Edinburgh
name: David E Newby, MD PhD
role: STUDY_CHAIR
affiliation: Umeå University
name: Anders Blomberg, MD PhD
role: STUDY_DIRECTOR
affiliation: Umeå Univerisity
name: Thomas Sandström, MD PhD
role: STUDY_DIRECTOR
affiliation: University of Edinburgh
name: Amanda L Hunter, MBChB
role: PRINCIPAL_INVESTIGATOR
References:
citation: Hunter AL, Unosson J, Bosson JA, Langrish JP, Pourazar J, Raftis JB, Miller MR, Lucking AJ, Boman C, Nystrom R, Donaldson K, Flapan AD, Shah AS, Pung L, Sadiktsis I, Masala S, Westerholm R, Sandstrom T, Blomberg A, Newby DE, Mills NL. Effect of wood smoke exposure on vascular function and thrombus formation in healthy fire fighters. Part Fibre Toxicol. 2014 Dec 9;11:62. doi: 10.1186/s12989-014-0062-4.
citation: Langrish JP, Watts SJ, Hunter AJ, Shah AS, Bosson JA, Unosson J, Barath S, Lundback M, Cassee FR, Donaldson K, Sandstrom T, Blomberg A, Newby DE, Mills NL. Controlled exposures to air pollutants and risk of cardiac arrhythmia. Environ Health Perspect. 2014 Jul;122(7):747-53. doi: 10.1289/ehp.1307337. Epub 2014 Mar 25.