Table 1.
Baseline characteristics of study population
| Characteristic | Alla N = 404 |
Cotton Workera N = 178 |
Silk Workera N = 226 |
p-valueb |
|---|---|---|---|---|
| 8-hour TWA Endotoxin (EU/m3)c | <0.001 | |||
| ≤ 50 | 237 (58.7%) | 11 (6.2%) | 226 (100%) | |
| 50 - 1,500 | 61 (15.1%) | 61 (34.3%) | 0 (0%) | |
| 1,500 - 2,300 | 35 (8.7%) | 35 (19.7%) | 0 (0%) | |
| 2,300 - 3,900 | 37 (9.2%) | 37 (20.8%) | 0 (0%) | |
| > 3900 | 34 (8.4%) | 34 (19.1%) | 0 (0%) | |
| Age (years) | 64 ± 9 | 63 ± 9 | 64 ± 9 | 0.6 |
| Gender | 0.8 | |||
| Female | 267 (66.1%) | 119 (66.9%) | 148 (65.5%) | |
| Male | 137 (33.9%) | 59 (33.1%) | 78 (34.5%) | |
| BMI | 24.2 ± 3.4 | 24.7 ± 3.6 | 23.7 ± 3.1 | 0.008 |
| Smoking status | 0.7 | |||
| Current | 83 (20.5%) | 40 (22.5%) | 43 (19.0%) | |
| Former | 30 (7.4%) | 12 (6.7%) | 18 (8.0%) | |
| Never | 291 (72.0%) | 126 (70.8%) | 165 (73.0%) | |
| Work history (years) | 25 ± 8 | 24 ± 7 | 26 ± 9 | 0.086 |
| Chronic bronchitis | 35 (8.7%) | 18 (10.1%) | 17 (7.5%) | 0.4 |
| Chronic cough | 11 (2.7%) | 4 (2.2%) | 7 (3.1%) | 0.8 |
| Dyspnea | 94 (23.3%) | 40 (22.5%) | 54 (23.9%) | 0.7 |
| PRISm | 10 (2.5%) | 5 (2.8%) | 5 (2.8%) | 0.8 |
| Airway obstruction | 55 (13.6%) | 23 (12.9%) | 32 (14.2%) | 0.7 |
| GOLD staged | 0.8 | |||
| 1 | 42 (76.4%) | 17 (73.9%) | 25 (78.1%) | |
| 2 | 11 (20.0%) | 5 (21.7%) | 6 (18.8%) | |
| 3 | 1 (1.8%) | 0 (0%) | 1 (3.1%) | |
| 4 | 1 (1.8%) | 1 (4.3%) | 0 (0%) | |
| Spirometry | ||||
| FEV1 (ml) | 2,314 ± 601 | 2,305 ± 639 | 2,321 ± 570 | 0.4 |
| ≤ 2756.88 | 323 (80.0%) | 141 (79.2%) | 182 (80.5%) | 0.7 |
| pp FEV1, (%) | 107 ± 18 | 105 ± 18 | 109 ± 18 | 0.066 |
| ≤ 1.22 | 323 (80.0%) | 147 (82.6%) | 176 (77.9%) | 0.2 |
| FEV1/FVC | 0.77 ± 0.07 | 0.77 ± 0.07 | 0.77 ± 0.08 | 0.5 |
| Small airway measures | ||||
| Exp−856 | 0.22 ± 0.13 | 0.21 ± 0.12 | 0.23 ± 0.14 | 0.5 |
| ≤ 0.31 | 323 (80.0%) | 148 (83.1%) | 178 (78.8%) | 0.2 |
| E/I MLA | 0.86 ± 0.07 | 0.86 ± 0.06 | 0.86 ± 0.07 | 0.9 |
| ≤ 0.90 | 323 (80.0%) | 145 (81.5%) | 178 (78.8%) | 0.5 |
| RVC−856 to −950 | −0.36 ± 0.16 | −0.36 ± 0.16 | −0.36 ± 0.16 | 0.7 |
| ≤ −0.22 | 323 (80.0%) | 144 (80.9%) | 179 (79.2%) | 0.7 |
| Residual−856 | 0.00 ± 0.12 | 0.00 ± 0.11 | 0.00 ± 0.12 | >0.9 |
| ≤ 0.08 | 323 (80.0%) | 148 (83.1%) | 175 (77.4%) | 0.2 |
Note: n (%) and Mean ± SD were reported for categorical variables and continuous variables, respectively. Abbreviations: TWA, Time-weighted Average; GOLD, Global Initiative for Chronic Obstructive Lung Disease; FEV1, Forced Expiratory Volume in the first 1 second; pp FEV1, percent predicted FEV1; FVC, Forced Vital Capacity; Exp−856, percent gas trapping; E/I MLA, expiratory to inspiratory ratio of mean lung attenuation; RVC−856 to −950, relative volume change of voxels with attenuation between −856 HU and −950 HU; Residual−856, residuals from the linear regression of Exp−856 on the percent of voxels with attenuation less than −950 HU.
Characteristics of 404 textile workers who had inspiratory/expiratory CT scans were collected in 2011 or 2016, including 178 cotton textile workers and 226 silk textile workers.
Wilcoxon rank sum test; Pearson’s Chi-square test; Fisher’s exact test
50 EU/m3 represents the reference level. 1500 EU/m3 is the 40th percentile, 2300 EU/m3 is the 60th percentile, and 3900 EU/m3 is the 80th percentile.
The GOLD stage is reported for the subset of 55 workers with COPD (FEV1/FVC < 0.7).