Table 1. Subjects’ characteristics.
| Variables | ACOS (n=258) | COPD (n=982) | Asthma (n=672) | NAD (n=9,744) | P |
|---|---|---|---|---|---|
| Age (years), n (%) | |||||
| <40 | 14 (5.4) | 89 (9.1) | 191 (28.4) | 3,201 (32.9) | <0.001† |
| ≥40 and <60 | 75 (29.1) | 246 (25.0) | 247 (36.8) | 4,273 (43.9) | |
| ≥60 | 169 (65.5) | 647 (65.9) | 234 (34.8) | 2,270 (23.3) | |
| Gender, n (%) | |||||
| Male | 165 (64.0) | 680 (69.2) | 251 (37.4) | 4,080 (41.9) | <0.001† |
| Female | 93 (36.0) | 302 (30.8) | 421 (62.6) | 5,664 (58.1) | |
| BMI, n (%) | |||||
| Underweight | 15 (5.8) | 46 (4.7) | 16 (2.4) | 261 (2.7) | <0.001† |
| Normal | 165 (64.0) | 697 (71.0) | 351 (52.2) | 6,017 (61.8) | |
| Overweight | 78 (30.2) | 239 (24.3) | 305 (45.4) | 3,466 (35.6) | |
| Lung function, mean ± SD or n (%) | |||||
| FVC % predicted | 84.8±16.10 | 90.0±15.17 | 9.4±13.23 | 92.5±11.97 | <0.001‡ |
| FEV1% predicted | 67.0±17.39 | 76.4±15.98 | 90.0±12.85 | 93.5±12.08 | <0.001‡ |
| FEV1/FVC | 0.59±0.11 | 0.63±0.07 | 0.80±0.06 | 0.82±0.06 | <0.001‡ |
| FEV1 <50% predicted | 43 (16.7) | 55 (5.6) | 4 (0.6) | 12 (0.1) | <0.001† |
| FEV1 ≥50% predicted | 215 (83.3) | 927 (94.0) | 668 (99.4) | 9,732 (99.9) | |
| Chronic bronchitis, n (%) | |||||
| No | 247 (95.7) | 974 (99.2) | 671 (99.9) | 9,739 (99.9) | <0.001† |
| Yes | 11 (4.3) | 8 (0.8) | 1 (0.1) | 5 (0.1) | |
| Smoking status, n (%) | |||||
| Current | 109 (42.2) | 308 (31.4) | 254 (37.) | 2,019 (20.7) | <0.001† |
| Former | 67 (26.0) | 352 (35.8) | 66 (9.8) | 1,892 (19.4) | |
| Never | 82 (31.8) | 322 (32.8) | 352 (52.4) | 5,833 (59.9) | |
| Education (years), n (%) | |||||
| <12 | 186 (72.1) | 590 (60.1) | 323 (48.1) | 3,318 (34.1) | <0.001† |
| 12 | 47 (18.2) | 218 (22.2) | 175 (26.0) | 3,065 (31.5) | |
| >12 | 25 (9.7) | 174 (17.7) | 174 (25.9) | 3,361 (34.5) | |
| Household income, n (%) | |||||
| 1st quartile (lowest) | 140 (54.3) | 474 (48.3) | 221 (32.9) | 2,245 (23.0) | <0.001† |
| 2nd quartile | 43 (16.7) | 193 (19.7) | 139 (20.7) | 2,142 (22.0) | |
| 3rd quartile | 54 (20.9) | 194 (19.8) | 180 (26.8) | 3,230 (33.2) | |
| 4th quartile (highest) | 21 (8.1) | 121 (12.3) | 132 (19.6) | 2,127 (21.8) | |
†, Chi-square test; ‡, ANOVA. ACOS, asthma COPD overlap syndrome; COPD, chronic obstructive pulmonary disease; NAD, no airway disease; BMI, body mass index; FVC, forced vital capacity; FEV1, forced expiratory volume in 1 second.