Condition category
Signs and Symptoms
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Air pollution can seriously affect people’s health; young children and older adults are particularly vulnerable to its effects. Air pollution, which mainly comes from traffic exhaust fumes, can cause breathing and heart problems and has been linked to disease and early death. Older adults are encouraged to be physically active and carry out daily activities such as walking, cycling and taking part in sports to maintain their health. However, many physical activities are performed outdoors. Normally, outdoor activities are a healthy way to keep fit, but when air pollution levels are high, outdoor exercise may have a negative effect on a person’s health. The Air Quality Health Index (AQHI) is a health risk communication tool which provides information on current and forecast air quality conditions. The AQHI tool provides advice to guide outdoor activities and to reduce the risk of adverse health effects from exposure to high levels of air pollution. This study aims to test whether following AQHI advice is effective in reducing the risk of adverse health effects of air pollution in healthy older adults.

Who can participate?
Healthy adults 55 years and older.

What does the study involve?
Participants are randomly allocated into one of two groups. Those in group 1 (intervention group) are asked to exercise every day, but to exercise indoors rather than outdoors when the forecast AQHI value is 5 or greater. Those in group 2 (control group) are asked to exercise outdoors daily. All participants complete 10 weeks of daily health measures before and after exercise at home. Health measures are also carried out every week at a central site for the duration of the study.

What are the possible benefits and risks of participating?
Participants will not benefit directly from participating in this study; however there is financial compensation at the completion of data collection. This study will entail a moderate time commitment of approximately 1 ½ hours per day and 4 hours once per week for 10 weeks. Clinical tests may cause some discomfort, however, any discomfort should be brief and transient. Some participants may experience some skin irritation at the electrode sites, but this reaction will disappear.

Where is the study run from?
University of Western Ontario (Canada)

When is the study starting and how long is it expected to run for?
Feb 2015 to August 2016

Who is funding the study?
Health Canada (Canada)

Who is the main contact?
Dr D Stieb

Trial website

Contact information



Primary contact

Dr David Stieb


Contact details

445-757 West Hastings St. - Federal Tower
V6C 1A1
604 666 3701

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

A randomised controlled trial of the effectiveness of the Air Quality Health Index (AQHI) in reducing cardiac and respiratory adverse effects of air pollution in adults 55 and over


Study hypothesis

Reducing outdoor physical activity in accordance with advice provided through the Air Quality Health Index will reduce adverse cardiac and respiratory effects of air pollution in adults 55 and over.

Ethics approval

Health Canada/Public Health Agency of Canada, 23/04/2015, ref: 2012-0035.

Study design

Single-centre randomised trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet


Cardiac and respiratory health


1. The intervention group will be asked to exercise indoors rather than outdoors and avoid other outdoor activity prior to physiological testing when the maximum AQHI is forecast to be 5 or higher (on the remaining days they will exercise outdoors). The intervention group will receive instructions for a simple indoor exercise routine that can be completed on designated days.
2. The control group will exercise outdoors daily

Intervention type



Drug names

Primary outcome measure

Weekly measures before and after 30 minutes of mild activity:
1. Heart rate variability (Holter monitoring)
2. Endothelial function (Reactive Hyperemia Index - Peripheral artery tone)
3. Oxygen saturation (finger oximeter)
4. Blood pressure (automated sphygmomanometer)
5. Fraction of exhaled Nitric Oxide (exhaled NO sensor)
6. Spirometric measures (spirometer)
7. Urinary oxidative stress markers (vascular endothelial growth factor (VEGF), 8-isoprostane, malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG))

Secondary outcome measures

Respiratory symptoms.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Participants must be 55 years of age or older
2. Non-smokers
3. Not exposed to environmental tobacco smoke at home
4. No seasonal allergies

Participant type

Healthy volunteer

Age group




Target number of participants


Total final enrolment


Participant exclusion criteria

1. Unstable angina
2. Atrial flutter
3. Atrial fibrillation
4. Paced rhythm
5. Left bundle branch block
6. Implanted cardioverter-defibrillator (ICD)
7. Participants with allergies to latex or adhesives will be excluded

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

University of Western Ontario
1151 Richmond St
N6A 3K7

Sponsor information


Health Canada

Sponsor details

50 Colombine Drwy
Tunney's Pasture
K1A 0K9

Sponsor type




Funder type


Funder name

Health Canada

Alternative name(s)

Santé Canada,

Funding Body Type

government organisation

Funding Body Subtype

National government



Results and Publications

Publication and dissemination plan

Papers will be submitted to peer reviewed journals regarding primary study findings and possibly secondary findings regarding effect modification by genotype. It is estimated that the first paper will be submitted by 31/12/2018.

IPD sharing statement
The datasets generated during and/or analysed during the current study are not expected to be made available due to privacy restrictions.

Intention to publish date


Participant level data

Not expected to be available

Basic results (scientific)

Publication list

2019 results in (added 13/12/2019)

Publication citations

Additional files

Editorial Notes

13/12/2019: Publication reference and total final enrolment number added. 15/02/2018: Publication and dissemination plan updated, IPD sharing statement added.