Table I.

Characteristics of never-smokers and of smokers with and without COPD

Never-SmokersSmokers without COPDSmokers with COPDp Valuea
Subjects examined152030
Age (years)58.0 (50.0–54.5)b56.5 (48.5–68.0)63.5 (57.3–68.5)0.4903
Gender (male/female)8/712/823/7
Smoking history (packs/year)047.5 (35.0–52.5)60.0 (40.0–67.5)0.2785
Smoking status (current/former)020/014/16
Diagnosis: lung cancer245
Pre-β2 agonist FEV1e (%)101.0 (100.0–117.0)95.0 (86.3–100.0)61.5 (50.8–64.8)cd<0.0001
Post-β2 agonist FEV1 (%)108.0 (104.3–123.8)99.5 (89.3–101.8)66.0 (56.3–71.8)cd<0.0001
Pre-β2 agonist FEV1/FVC (%)80.9 (79.6–84.6)76.3 (72.9–80.8)53.6 (46.5–60.1)cd<0.0001
Post-β2 agonist FEV1/FVC (%)83.7 (80.8–86.1)77.9 (73.8–82.5)56.2 (40.7–59.3)cd<0.0001
PaO2 (mmHg)N.D.98.0 (97.0–99.0)82.0 (69.3–87.0)<0.0001
PaCO2 (mmHg)N.D.39.0 (38.8–40.0)40.0 (38.1–41.3)0.2254
pHN.D.7.40 (7.40–7.41)7.41 (7.40–7.43)0.1968
FRC (% predicted)N.D.102.0 (93.0–119.5)121.0 (105.8–146.5)0.0070
RV (% predicted)N.D.94.0 (82.5–108.5)119.0 (100.3–134.3)0.0012
TLC (% predicted)N.D.99.0 (88.0–105.0)105.0 (94.3–120.0)0.1007
DLCO (% predicted)N.D.89.0 (86.0–98.5)72.0 (59.0–80.5)<0.0001
On inhaled steroids002
On anticholinergics0030
  • a Significance was assessed with the use of Kruskal-Wallis test, except for smoking history; pre- and post-β2 agonists FEV1, pre- and post-β2 agonists FEV1/FVC, PaO2, PaCO2, pH, FRC, RV, TLC, and DLCO, for which the Mann-Whitney U test was applied.

  • b Results are expressed as median (interquartile range) of the indicated number of values.

  • c p < 0.05, as compared with never-smokers;

  • d p < 0.05, as compared with smokers without COPD.

  • e FEV1, Forced expiratory volume in 1 s; FVC, forced vital capacity; Pa, partial pressure; FRC, functional residual capacity; RV, residual volume; TLC, total lung capacity; N.D., not done.