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:

1. Individuals with mild COPD (GOLD 1; post-bronchodilator FEV1/FVC<0.70 and FEV1≥80% predicted)

2. Individuals with moderate-severe COPD (GOLD ≥2; post-bronchodilator FEV1/FVC<0.70 and FEV1<80% predicted)

3. Sex and age matched (±2 years) ever-smokers without COPD

4. Sex and age matched (±2 years) never-smokers without COPD