Table 1

Demographic and clinical data

Healthy never smokers (NS) Asymptomatic smokers (AS) Chronic bronchitis (CB) and recurrent exacerbations
n432433
Age (years)53 (32–73)49 (34–64)50 (37–68)
FEV1 (% pred)103 (81–133)1-a 99 (83–129)1-b 86 (63–111)1-a 1-b
Pack years027 (11–70)1-c 36 (13–82)1-c
Current smoking (cigarettes/day)015 (10–35)1-c 20 (10–40)1-c
Duration of smoking (years)034 (22–49)34 (23–54)
Duration of CB (years)0010 (3–40)
No of exacerbations in 2 yrs006 (4–20)
Male/female17/2611/139/24

  • Data are presented as median values with range in parentheses.

  • FEV1 = forced expiratory volume in one second.

  • ↵1-a NS v CB, p<0.001;

  • ↵1-b AS v CB, p<0.001;

  • ↵1-c AS v CB, p<0.01.