Table 1 The basic characteristics of the study population
Variables | Control (n = 881) | All asthmatics (n = 910) | P value | Intermittent asthmatics (n = 537) | Persistent asthmatics (n = 373) | P trend | ||
|---|---|---|---|---|---|---|---|---|
|  |  | Mild (n = 246) | Moderate (n = 96) | Severe (n = 31) |  | |||
Age (years, Mean ± SD) | 46.63 ± 14.40 | 45.64 ± 14.11 | 0.1424 | 46.91 ± 14.36 | 43.76 ± 14.05 | 44.31 ± 12.31 | 42.71 ± 13.77 | 0.0040 |
Female (yes, %) | 522 (59.25) | 543 (59.67) | 0.8565 | 320 (59.59) | 148 (60.16) | 60 (62.50) | 15 (48.39) | 0.7487 |
Occupational hazards exposure (yes, %) | 306 (34.73) | 337 (37.03) | 0.3105 | 205 (38.18) | 82 (33.33) | 38 (39.58) | 12 (38.71) | 0.8230 |
Family history of asthma (yes, %) | 5 (0.57) | 100 (10.99) | < 0.0001 | 61 (11.36) | 19 (7.72) | 15 (15.63) | 5 (16.13) | 0.4609 |
Exercise (yes, %) | 417 (47.33) | 252 (27.69) | < 0.0001 | 176 (32.77) | 59 (23.98) | 11 (11.46) | 6 (19.35) | < 0.0001 |
Keeping pets (yes, %) | 132 (14.98) | 153 (16.81) | 0.2898 | 86 (16.01) | 39 (15.85) | 14 (14.58) | 14 (45.16) | 0.0313 |
Planting flowers (yes, %) | 178 (20.20) | 192 (21.10) | 0.6401 | 123 (22.91) | 53 (21.54) | 10 (10.42) | 6 (19.35) | 0.0353 |
Smoking status (N, %) |  | < 0.0001 |  | 0.1750 | ||||
 No smoking | 647 (73.44) | 718 (78.90) |  | 427 (79.52) | 193 (78.46) | 77 (80.21) | 21 (67.74) |  |
 Former smoking | 22 (2.50) | 74 (8.13) | 46 (8.57) | 20 (8.13) | 6 (6.25) | 2 (6.45) | ||
 Current smoking | 212 (24.06) | 118 (12.97) | 64 (11.92) | 33 (13.41) | 13 (13.54) | 8 (25.81) | ||
Passive smoking (yes, %) | 302 (34.28) | 217 (23.85) | < 0.0001 | 143 (26.63) | 49 (19.92) | 23 (23.96) | 2 (6.45) | 0.5931 |
Drinking (N, %) |  | < 0.0001 |  | 0.6185 | ||||
 No drinking | 671 (76.16) | 767 (84.29) |  | 457 (85.10) | 206 (83.74) | 78 (81.25) | 26 (83.87) |  |
 Former drinking | 18 (2.04) | 49 (5.38) | 26 (4.84) | 12 (4.88) | 9 (9.38) | 2 (6.45) | ||
 Current drinking | 192 (21.79) | 94 (10.33) |  | 54 (10.06) | 28 (11.38) | 9 (9.38) | 3 (9.68) |  |
Sleeping quality (N, %) |  | < 0.0001 |  | 0.0015 | ||||
 Good | 538 (61.07) | 250 (27.47) |  | 172 (32.03) | 59 (23.98) | 13 (13.54) | 6 (19.35) |  |
 Impaired | 278 (31.56) | 442 (48.57) | 243 (45.25) | 127 (51.63) | 55 (57.29) | 17 (54.84) | ||
 Poor | 65 (7.38) | 218 (23.96) | 122 (22.72) | 60 (24.39) | 28 (29.17) | 8 (25.81) | ||
BMI (kg/m2, Mean ± SD) | 23.22 ± 3.36 | 23.03 ± 3.48 | 0.2261 | 23.14 ± 3.54 | 23.02 ± 3.45 | 22.86 ± 3.39 | 21.63 ± 2.56 | 0.0523 |
Lung function parameters | ||||||||
 FVC (L, Mean ± SD) | 3.11 ± 0.88 | 2.91 ± 1.03 | < 0.0001 | 2.84 ± 1.01 | 3.00 ± 1.02 | 3.07 ± 1.05 | 2.98 ± 1.20 | 0.0197 |
 FEV1 (L, Mean ± SD) | 2.61 ± 0.69 | 2.11 ± 0.84 | < 0.0001 | 2.09 ± 0.82 | 2.20 ± 0.84 | 2.04 ± 0.85 | 1.94 ± 1.02 | 0.7273 |
 % PRED FVC, % (Mean ± SD) | 102.77 ± 23.75 | 88.65 ± 23.12 | < 0.0001 | 87.77 ± 22.87 | 90.39 ± 22.65 | 90.60 ± 23.48 | 83.67 ± 29.19 | 0.5332 |
 % PRED FEV1, % (Mean ± SD) | 98.05 ± 24.68 | 77.82 ± 26.19 | < 0.0001 | 77.86 ± 25.63 | 80.12 ± 24.73 | 75.42 ± 30.28 | 66.22 ± 30.69 | 0.1292 |
 FEV1/FVC (%) | 84.73 ± 8.18 | 72.52 ± 15.18 | < 0.0001 | 73.88 ± 15.02 | 73.08 ± 13.39 | 66.26 ± 16.48 | 63.79 ± 19.68 | < 0.0001 |
 PEF | 5.52 ± 2.13 | 4.63 ± 2.08 | < 0.0001 | 4.56 ± 2.08 | 4.79 ± 2.09 | 4.70 ± 2.03 | 4.27 ± 2.09 | 0.6808 |
sCD14 (ng/mL, Median, 25th~75th) | 708.21 (499.91, 967.66) | 500.47 (334.59, 744.65) | < 0.0001 | 555.99 (364.86, 791.24) | 421.02 (296.82, 671.69) | 460.53 (315.78, 677.69) | 398.56 (258.49, 534.96) | < 0.0001 |