Table 2

Characteristics at first examination according to smoking status at second examination for the pooled study population

Never smokers (n=4006)Ex-smokers (n=2880)Quitters (n=1454)Light smokers (n=3189)Reducers (n=832)Heavy smokers (n=7348)p value*
Results are presented as absolute values, percentages, or mean (SD) values.
*p values represent differences between the reducers and the continuous heavy smokers.
†Two sample t tests. All other are χ2 tests with two tailed p values.
‡Results only from the CCHS, 1st survey 1976–8, n=7823.
§Results only from the CCHS, 3rd survey 1991–3, n=7016.
Sex (% men)33.765.961.247.572.166.60.001
Age (years)49.5 (11.9)51.5 (10.4)50.5 (11.0)50.1 (10.7)51.3 (10.3)48.0 (9.4)<0.001†
Tobacco consumption (g/day)14.5 (12.2)9.0 (4.2)22.4 (12.2)19.9 (8.6)<0.001†
Inhalers (%)60.474.070.678.0<0.001
Type of tobacco smoked
    Cigarettes (%)51.173.933.257.9<0.001
    Cigars, cheroots, pipe, mixed (%)48.926.166.842.1<0.001
Chronic mucus (%)3.95.910.49.110.414.10.004
Pack years of smoking19.4 (18.1)14.0 (8.4)27.0 (20.9)30.9 (19.3)<0.001†
FEV1 (% predicted)‡89.6 (16.3)87.9 (18.9)81.8 (19.9)87.4 (16.5)80.9 (16.3)82.0 (16.7)0.31
Expired CO (ppm)§2.2 (1.3)2.4 (2.2)4.0 (5.9)8.4 (7.7)8.7 (8.1)13.2 (10.0)<0.001†
Admission for COPD, n (%)71 (1.8)106 (3.7)83 (5.7)228 (7.1)82 (9.8)690 (9.4)