Characteristics of the 3684 participants by COPD status
| All (n=3684) | No COPD (n=3480) | COPD (n=204) | P value | |
| n (%) | n (%) | n (%) | ||
| Gender | ||||
| Male | 1734 (47.1) | 1631 (46.9) | 103 (50.5) | 0.3 |
| Female | 1950 (52.9) | 1849 (53.1) | 101 (49.5) | |
| Age | ||||
| 40–64 years | 1838 (49.9) | 1760 (50.6) | 78 (38.2) | 0.001 |
| 65–84 years | 1846 (50.1) | 1720 (49.4) | 126 (61.8) | |
| Smoking (27 missing) | ||||
| Current | 442 (12.1) | 377 (10.9) | 65 (31.9) | <0.001* |
| Previous | 1729 (47.3) | 1609 (46.6) | 120 (58.8) | |
| Never | 1486 (40.6) | 1467 (42.5) | 19 (9.3) | |
| Self-reported diseases | ||||
| Hypertension (102 missing) | 1287 (35.9) | 1222 (36.1) | 65 (32.8) | 0.3 |
| Myocardial infarction (155 missing) | 171 (4.8) | 155 (4.7) | 16 (8.2) | 0.03 |
| Heart failure (158 missing) | 101 (2.9) | 96 (2.9) | 5 (2.6) | 0.8 |
| Atrial fibrillation (156 missing) | 277 (7.9) | 255 (7.6) | 22 (11.3) | 0.06 |
| Diabetes (124 missing) | 219 (6.2) | 211 (6.3) | 8 (4.1) | 0.2 |
| COPD (143 missing) | 140 (4.0) | 79 (2.4) | 61 (31.9) | <0.001 |
| Asthma (129 missing) | 393 (11.1) | 331 (9.8) | 62 (32.0) | <0.001 |
| Crackles | ||||
| Observer 1 | 388 (10.5) | 351 (10.1) | 37 (18.1) | <0.001 |
| Observer 2 | 461 (12.5) | 422 (12.1) | 39 (19.1) | 0.003 |
| Basal inspiratory crackles | ||||
| Observer 1 unilateral | 221 (6.0) | 200 (5.7) | 21 (10.3) | <0.001* |
| Bilateral | 85 (2.3) | 73 (2.1) | 12 (5.9) | |
| Observer 2 unilateral | 246 (6.7) | 228 (6.6) | 18 (8.8) | 0.001* |
| Bilateral | 77 (2.1) | 64 (1.8) | 13 (6.4) |
*Analysed by χ2 for trend.
COPD, chronic obstructive pulmonary disease.