Diagnosis of the main respiratory diseases among 1257 enrolled patients
| Disease | n (%) |
| COPD | 519 (41.5) |
| Bronchial asthma | 345 (27.6) |
| Nose and throat disease | 129 (10.3) |
| Lung cancer | 20 (1.6) |
| Bronchiectasis | 41 (3.3) |
| Tuberculosis and its sequels | 9 (0.7) |
| Acute lower respiratory tract infection | 65 (5.2) |
| Fibrocystic disease | 3 (0.2) |
| Interstitial lung disease | 28 (2.2) |
| Other chronic lung disease | 98 (7.4) |
COPD: chronic obstructive pulmonary disease