Face Masks to Reduce the Adverse Effects of Diesel Exhaust Inhalation

Study Overview
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Brief Summary
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Air pollution exposure is a major environmental and public health concern. The findings from controlled exposure studies have given biological plausibility to the epidemiological associations, and have defined important pathways that may be amenable to intervention. Ultimately, there is a need to address how one may protect the public from these detrimental effects. Two studies have been performed assessing the cardiovascular effects of wearing a face mask in a highly polluted urban area in China in healthy volunteers and patients with coronary heart disease. These demonstrated lower blood pressure and increased heart rate variability when wearing a face mask as compared to not. The investigators aim to test if wearing a highly efficient face mask during exposure to dilute diesel exhaust abrogates the well-known adverse cardiovascular effects.

Official Title
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Face Masks to Reduce the Adverse Effects of Diesel Exhaust Inhalation

Conditions
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Healthy

Intervention / Treatment
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* Other: Diesel exhaust exposure with filtered facemask
* Other: Diesel exhaust exposure with sham mask


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy males Non-smoking All subjects undergo a general health examination and are required to have normal clinical examination, ECG, blood tests and lung function Exclusion Criteria: Metabolic or cardiovascular disease Asthma or other respiratory disease Respiratory infection within 2 weeks of the study Antioxidant- and/or vitamin supplementation within 1 week prior to, as well as during the course of the study. (incl vitamin C, Acetylcysteine) Smokers or regular snus usage

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Commercially available highly-efficient facemask<br> | Other: Diesel exhaust exposure with filtered facemask<br>* 1 hour exposure to dilute diesel exhaust (approximate particle matter concentration 300 mcg/m3) during intermittent exercise while wearing a filtered facemask.<br>|
| Sham Comparator: Sham facemask<br> | Other: Diesel exhaust exposure with sham mask<br>* 1 hour exposure to dilute diesel exhaust (approximate particle matter concentration 300 mcg/m3) during intermittent exercise while wearing a sham facemask.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vascular vasomotor function | Forearm venous occlusion plethysmography to measure forearm blood flow during unilateral intrabrachial infusion of endothelial-dependent and -independent vasodilators. Assessment is shown in ml/100ml tissue/min. | 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fibrinolytic function | Tissue plasminogen activator was analysed in blood samples taken after bradykinin infusions in order to assess fibrinolytic function (ng/ml). | 2 hours | 
| Blood pressure | Ambulatory blood pressure monitors are worn by subjects for 24 hours during and after exposure. | 24 hours | 
| Heart rate variability | Holter ECGs are worn by subjects during and for 24 hours post exposure. This will be assessed for heart rate variability (HRV). | 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Diesel exhaust, Air pollution, Intervention, Plethysmography