With longitudinal evaluations and detailed characterization of study subjects using a range of assessment tools, CanCOLD is an invaluable resource to catalyze COPD research.
CanCOLD is the first observational cohort specific to COPD having recruited its participants from the general population rather than more convenient recruitment in clinical settings. This strategy better mirrors prevalent COPD populations at large and provides proper representation of typically underrepresented groups in COPD studies; early disease, female population, individuals who have never smoked (up to 30% of the COPD population) and those with physician undiagnosed disease (up to 70% of the COPD population).
CanCOLD originated from the cross-sectional Burden of Obstructive Lung Disease (BOLD) study, an international initiative measuring the prevalence of COPD and its risk factors in different regions around the world, which included a data collection site in Vancouver, Canada. Expanding on this initiative nationally, the Canadian Obstructive Lung Disease (COLD) population-based prevalence study was established by randomly sampling a total of 6,551 non-institutionalized men and women aged ≥ 40 years from 9 Canadian cities: Vancouver, Montreal, Calgary, Quebec, Halifax, Toronto, Kingston, Saskatoon, and Ottawa.
With the aim of establishing a longitudinal population-based COPD cohort in Canada, COLD study participants within four target subsets were contacted to enroll in CanCOLD:
- Individuals with mild COPD (GOLD 1; post-bronchodilator FEV1/FVC<0.70 and FEV1≥80% predicted)
- Individuals with moderate-severe COPD (GOLD ≥2; post-bronchodilator FEV1/FVC<0.70 and FEV1<80% predicted)
- Sex and age matched (±2 years) ever-smokers without COPD
- Sex and age matched (±2 years) never-smokers without COPD
Data Collection Waves
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. A wide range of physical measures and assessment tools are used including anthropometric measures, validated questionnaires, blood samples, pulmonary function tests, cardiopulmonary exercise test (CPET) and multidetector computerized tomography scan (CT Scan).
Respiratory health is additionally evaluated by telephone contact every 3 months, when participants respond to a COPD exacerbation questionnaire, with questions on symptom changes, medication and health service use.
CanCOLD data can be linked to information held in provincial administrative and vital statistics databases such as health care utilization, medication intake, and cause of mortality. Finally, in order to assess the relationship of chronic respiratory disease development and progression with environmental factors such as ambient air pollution exposure and climate and weather events, data distributed by the Canadian Urban Environmental Health Research Consortium (CANUE) is linked to CanCOLD data.
COLD prevalence study N = 6551
2005 to 2016
|n = 1552||n = 1211||n = 600|
|n = 586||n = 549||n = 541|
|n = 533||n = 504||n = 475|
COPD cases refused (n = 286)
or no contact (n = 266)
CanCOLD Visit 1 (baseline assessment) N=1561
2009 to 2015
|n = 435||n = 355||n = 129|
|n = 85||n = 127||n = 74|
|n = 136||n = 104||n = 116|
Time lags between assessments
|CanCOLD v1 to v2||19 months||6 months||31 months|
|CanCOLD v2 to v3||18 months||3 months||50 months|
|CanCOLD v1 to v3||37 months||24 months||84 months|
|CanCOLD v2 to v3||6 months||3 months||14 months|
CanCOLD Visit 2 N=1019
2011 to 2015
CanCOLD Visit 3 N=1198
2013 to 2019
CanCOLD Visit 4
2022 to 2023