Table 1

 Characteristics of study subjects

COPD(n = 28)Never smokers(n = 20)Smokers(n = 14)Former smokers(n = 14)
FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; ICS, inhaled corticosteroids.
Data are presented as median (IQR).
*p<0.01 v never smokers; †p<0.001 v smokers; ‡p<0.05 v former smokers; §p<0.001 v never smokers; ¶p<0.001 v never smokers, smokers and former smokers.
Sex ratio (M/F)24/44/167/77/7
Age (years)64.0 (52–72)*†‡52.5 (42–56)51.0 (49–53)52.5 (46–63)
Smoking history (pack years)42.0 (26–55)‡§0.0 (0–0)35.0 (16–43)30.0 (9–42)
FEV1 (l)2.0 (1.7–2.3)¶3.0 (2.7–3.4)3.0 (2.5–3.3)3.4 (2.7–3.7)
FEV1 (% predicted)70.0 (63–78)¶105.5 (97–118)96.0 (91–101)108.0 (100–113)
FEV1/FVC (%)56.0 (49–65)¶80.5 (77–83)78.0 (73–82)78.5 (75–80)
Bronchodilators (Y/N)20/80/200/140/14
ICS (Y/N)17/110/200/140/14