Baseline demographic and clinical characteristics
| Intervention | Placebo | |||
| n | n | |||
| Age (years) | 33 | 66.0±6.8 | 31 | 66.4±7.8 |
| Sex (male/female) | 33 | 13/20 | 31 | 16/15 |
| Educational level | 33 | 31 | ||
| Primary school | 2 (6.1%) | 0 (0.0%) | ||
| Initial vocational education | 0 (0.0%) | 3 (9.8%) | ||
| High school | 10 (30.3%) | 10 (32.3%) | ||
| Intermediate vocational education | 6 (18.2%) | 8 (25.8%) | ||
| Higher vocational education | 12 (36.4%) | 10 (32.3%) | ||
| Academic | 3 (9.1%) | 0 (0.0%) | ||
| Smoking status (never/current/former) | 33 | 8/3/22 | 31 | 6/6/19 |
| Lung function | ||||
| GOLD stage (I/II/III/IV) | 31 | 8/11/11/1 | 30 | 5/15/7/3 |
| FEV1 (L) | 31 | 1.75±0.76 | 30 | 1.69±0.69 |
| FEV1 (% predicted) | 31 | 58.5 (44.7–82.5) | 30 | 60.6 (44.9–71.8) |
| FVC (L) | 31 | 3.55±1.03 | 30 | 3.49±0.98 |
| FEV1/FVC (%) | 31 | 49.0±14.7 | 30 | 48.4±14.7 |
| ACE-R (0–100) | 33 | 88 (82–93) | 31 | 88 (83–94) |
Data presented as mean±sd or median (interquartile range) depending on the normality of the distribution of the data, unless otherwise indicated. No parameters were significantly different between the groups. GOLD: Global Initiative for Obstructive Lung Disease; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; ACE-R: Addenbrooke's Cognitive Examination-Revised.