| Controls | COPD | ||||
| Nonsmoking | Smoking | GOLD 2 | GOLD 3 | GOLD 4 | |
| Subjects n | 46 | 183 | 179 | 186 | 60 |
| Age years | 61±8 | 53±8 | 62±7 | 64±7 | 64±6 |
| Height cm | 173±9 | 172±9 | 171±8 | 170±9 | 171±8 |
| Weight kg | 78±13 | 78±14 | 76±18 | 74±18 | 69±19 |
| BMI kg·m−2 | 26±3 | 26±4 | 26±5 | 25±5 | 24±5 |
| Smoking pack-years median (IQR) | 27 (17–39) | 35 (23–50) | 37 (24–50) | 38 (25–55) | |
| PaO2#kPa | 10.7±1.1 | 10.8±1.2 | 9.6±1.1 | 9.2±1.0 | 8.6±1.1 |
| 6MWD# m | 462±93 | 414±105 | 338±128 | ||
| Symptoms mean (IQR) | |||||
| mMRC# dyspnoea scale score | 0.1 (0–0) | 0.2 (0–0) | 1.1 (0–2) | 1.7 (1–2) | 2.3 (1.75–3) |
| SGRQ-C# score | 3 (0–5) | 5 (2–9) | 34 (19–51) | 44 (30–59) | 56 (49–68) |
| Spirometry | |||||
| FEV1 L | 3.3±0.7 | 3.4±0.7 | 1.9±0.4 | 1.3±0.3 | 0.8±0.2 |
| FEV1 % pred | 100±10 | 97±9 | 60±6 | 40±5 | 25±4 |
| FVC L | 4.1±0.9 | 4.4±0.9 | 3.6±0.9 | 3.2±0.9 | 2.6±0.8 |
| Plethysmography | |||||
| TLC# L | 6.5±1.3 | 6.5±1.3 | 7.0±1.4 | 7.2±1.4 | 7.8±1.3 |
| IC# L | 3.3±0.8 | 3.3±0.8 | 2.8±0.8 | 2.4±0.7 | 2.0±0.6 |
| RV# L | 2.1±0.5 | 1.8±0.6 | 2.8±0.9 | 3.4±0.9 | 4.5±1.0 |
Data are presented as mean±sd, unless otherwise stated. n=654. COPD: chronic obstructive pulmonary disease; GOLD: Global Initiative for Chronic Obstructive Lung Disease; BMI: body mass index; IQR: interquartile range; PaO2: arterial oxygen tension; 6MWD: 6-min walking distance; mMRC: modified Medical Research Council; SGRQ-C: St George’s Respiratory Questionnaire for COPD patients; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; TLC: total lung capacity; IC: inspiratory capacity; RV: residual volume. #: analysis restricted to patients with complete data.