Characteristics of participants
| Healthy never smokers | Healthy ever smokers | COPD never smokers | COPD ever smokers | |
| (A) Grouped by disease status and smoking history | ||||
| Subjects (n) | 37 | 71 | 30 | 94 |
| Women (%) | 54.1 | 45.1 | 80.0 | 36.2 |
| Age (years) | 55.9±8.5 | 55.7±9.3 | 68.1±10.3 | 60.4±7.3 |
| FEV1%pred | 112.6±20.3 | 101.2±16.1 | 73.0±20.7 | 58.8±23.2 |
| FEV1/FVC (%) | 81.7±5.1 | 77.5±6.2 | 56.5±15.2 | 56.3±11.6 |
| Current smokers (%) | – | 46.5 | – | 46.8 |
| Pack-years smoking | 0 | 29.6±39.6 | 0 | 36.9 ± 18.7 |
| Healthy normal BMI | Healthy low BMI | COPD normal BMI | COPD low BMI | |
| (B) Grouped by disease status and body mass index (BMI). | ||||
| Subjects (n) | 55 | 6 | 68 | 16 |
| BMI (kg/m2) | 26.3±3.3 | 20.9±0.6 | 26.8±3.4 | 21.1±1.3 |
| Women (%) | 40.0 | 66.7 | 33.8 | 50.0 |
| Age (years) | 56.4±7.2 | 53.3±4.1 | 60.0±6.9 | 59.9±7.8 |
| FEV1%pred | 110.8±17.5 | 108.2±5.9 | 56.4±21.5 | 52.3±22.6 |
| FEV1/FVC ratio ×100 | 80.6±6.0 | 79.5±6.4 | 55.5±12.2 | 54.4±8.4 |
| Pack-years smoking | 14.7±14.9 | 16.8±10.5 | 36.3±20.5 | 34.6±18.0 |
Values are expressed as percentage or mean±SD.
BMI, body mass index; COPD, chronic obstructive pulmonary disease; FEV1%, forced expiratory volume in 1 s (% predicted); FVC, forced vital capacity.