COLD prevalence
study N = 6551
2005 to 2016
Recruitment Sites
Vancouver
Montreal
Calgary
n = 1552
n = 1211
n = 600
Vancouver
Montreal
Calgary
n = 1552
n = 1211
n = 600
Vancouver
Montreal
Calgary
n = 1552
n = 1211
n = 600
COPD cases refused (n = 286) or no contact (n = 266)
CanCOLD Visit 1
(baseline assessment)
N=1561
2009 to 2015
Recruitment Sites
Vancouver
Montreal
Calgary
n = 435
n = 355
n = 129
Quebec
Halifax
Toronto
n = 85
n = 127
n = 74
Kingston
Saskatoon
Ottawa
n = 136
n = 104
n = 116
Time lags between assessments
Median
Min
Max
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
Visit 2
CanCOLD Visit 2 N=1019
2011 to 2015
Visit 3
CanCOLD Visit 3 N=1198
2013 to 2019
Visit 4