Inclusion criteria (all the following criteria apply) |
Aged 50–80 years inclusive | ✓ | ✓ | ✓ |
Baseline (post-bronchodilator) FEV1/FVC ratio | <70% | ≥70% | ≥70% |
CAT score <10 | | | ✓ |
BMI <35 (for CT scanning reasons) | ✓ | ✓ | ✓ |
Chronic mucus hypersecretion (≥3 months of cough and phlegm in a year in the past 2 years) | | ✓ | |
No exacerbations for ≥1 month prior to recruitment | ✓ | ✓ | |
Ever-smoker (lifetime exposure of ≥1 pack-year) or never-smoker (lifetime exposure of <1 pack-year) (for healthy participants, ever-smokers and passive smokers are not eligible) | ✓ | ✓ | ✓ |
Additional criteria for sub-cohort of COPD participants |
150 COPD participants with ≥1 moderate or severe exacerbation event within the past 2 years | ✓ | N/A | N/A |
60 COPD participants without inhaler maintenance treatment history for ≥12 months prior to the entry of the study | ✓ | N/A | N/A |