CanCOLD launches its 4th in-site assessment

CanCOLD launches its 4th in-site assessment

Editorial in the American Journal of Respiratory and Critical Care Medicine written by Peter Calverley highlights CanCOLD’s contribution to COPD research.

In winter 2022, the CanCOLD study launched visit 4, marking over 10 years of assessments since the baseline study (visit 1) in 2009. At each data collection wave, trained CanCOLD research staff collect a deep pool of information that can be queried to address research questions related to COPD and respiratory health. As with visit 1, this fourth in-site assessment includes a range of health and risk factor questionnaires, blood draws, spirometry tests, pulmonary function tests, cardiopulmonary exercise tests, and multidetector computerized tomography scans (CT Scans). With its rich data collection and over 10 years of follow-up time, this important visit will provide vital data to help us enhance our understanding of lung health in Canada. 

CanCOLD visit 4 follows three data collection waves that were completed between 2009 and 2019: baseline assessment occurred between 2009 to 2015, the first follow-up assessment (CanCOLD visit 2) was conducted approximately 18 months after baseline visit (2011 to 2015), and at 3 years post-baseline (2013 to 2019), CanCOLD completed visit 3. 

Continuous communication with CanCOLD subjects during and between visits has allowed the study to keep participants engaged and has allowed the project to successfully maintain longitudinal follow-up throughout the years. Currently, all 9 data collection sites are actively contacting participants to collect visit 4 data. By August 2023, close to 100 participants have already completed this fourth assessment site visit, which we expect to unfold until the end of 2024. A decade on, CanCOLD participants are proud to continue to contribute to the scientific knowledge of COPD for the benefit of COPD patient populations and society at large.

CanCOLD study shows associations between air pollution and respiratory health in Canada

CanCOLD study shows associations between air pollution and respiratory health in Canada

Although tobacco use is recognized as the single most important risk factor for the development and progression of COPD, 25–45% of individuals with COPD have never smoked. This highlights the importance of identifying risk factors beyond tobacco smoking such as environmental exposures and individual-level characteristics to inform preventive strategies, clinical diagnosis, and management of COPD. Long-term exposure to outdoor air pollution has been linked to reduced lung growth in children, as well as lung function decline and increased risk of COPD in adults. Recent studies also show that a mismatch between airway tree caliber and lung size (i.e., dysanaptic lungs) is associated with a higher risk of COPD. 

However, few studies on COPD have been conducted in locations with relatively low pollution concentrations such as Canada, and little is known about how air pollution exposure interacts with host factors such as abnormalities of airway and lung growth. A recent study making use of CanCOLD data, is the first study in Canada to examine associations of long-term ambient air pollution exposure with lung function and spirometrically confirmed COPD and is the first to examine how these associations interact with lung structure.


To perform this study, researchers linked lung function and behavioral risk factors data collected by CanCOLD with ambient air pollution concentrations provided by the Canadian Urban Environmental Health Research Consortium (CANUE). CanCOLD lung CT Scans were also used to determine the size of an individual’s airways relative to size of their lungs. Results showed that even exposure to low concentrations of outdoor air pollution found in Canada is associated with lower lung function in adults, i.e. the ability of the lungs to exchange oxygen and carbon dioxide through breathing. Specifically, investigators observed that small increases in two air pollutants, fine particulate matter (PM 2.5) and nitrogen dioxide (NO2), led to clinically relevant decreases in lung function. 

The findings also showed that individuals with dysanaptic lungs – a developmental mismatch between airway and lung size – could be more susceptible to the long-term effects of air pollution on lung function and COPD. The researchers found that individuals with smaller airways had lower lung function and were 87 per cent more likely to develop COPD compared to individuals with larger airways with similar exposure to air pollution. 

Dysanaptic lungs – A developmental mismatch between airway and lung size

The study therefore suggests that early-life lung development could play a key role in protecting from, or increasing susceptibility to air pollution-induced reductions in lung function and COPD in adulthood. 

Learn more in the RIMUHC’s coverage of CanCOLD’s publication. 


These CanCOLD results garnered media attention with articles written in CBC and La Presse.

CanCOLD editorial in AJRCCM

CanCOLD editorial in AJRCCM

Peter Calverley, a Professor of Respiratory Medicine at the University of Liverpool in the United Kingdom, presents CanCOLD as a “fine addition to the long and honorable history of Canadian research into the pathophysiology of COPD.” In his editorial for the American Journal of Respiratory and Critical Care Medicine, Prof Calverly specifically highlights the study’s role in helping to answer key research questions related to COPD. Thanks to CanCOLD, Canadian investigators are addressing novel questions regarding the pathophysiology of COPD. The author showcases how CanCOLD has spearheaded key advancements in the field of COPD research. CanCOLD’s significance resonates as
he underlines the critical data the study has previously unraveled regarding the early loss of small airways in COPD progression and the role of elevated blood eosinophil counts in accelerating disease progression, among other valuable insights.

Peter Calverley also highlights the breadth of CanCOLD’s exercise dataset which “takes our understanding of exercise limitation in COPD to a new level”. As he dissects CanCOLD’s latest publication by Phillips et al. (2022), that examines why individuals with mild COPD have greater breathlessness, Calverley outlines how the CanCOLD study “broadens our understanding of impaired exercise performance, suggests new approaches to its understanding, and will no doubt be succeeded by more exciting data.” The editorial underlines the lasting impact of CanCOLD’s findings in Canadian and international research. Read the full editorial here.