Table 1.
Characteristics of COPD cases and controls
| Variables | Controls (n = 48) | Cases | ||
|---|---|---|---|---|
| COPD without CWP patients (n = 41) | COPD with CWP patients (n = 35) | All COPD patients (n = 76) | ||
| Age (year) | 68.7 ± 6.7 | 69.5 ± 6.5 | 68.9 ± 6.8 | 69.2 ± 6.6 |
| Dust exposure duration (year) | 27.5 ± 9.1 | 28.2 ± 10.3 | 28.4 ± 5.3 | 28.3 ± 8.4 |
| Average dust concentration (mg/m3) | 20.7 ± 8.5 | 26.7 ± 4.2* | 27.9 ± 6.5* | 27.3 ± 5.4* |
| Cumulative dust exposure (mg/m3-years) | 556.2 ± 257.4 | 757.2 ± 306.7* | 796.9 ± 267.7* | 775.5 ± 288.2* |
| Smokers (%yes) | 39 (81.8) | 35 (85.4) | 28 (80.0) | 63 (82.9) |
| Amount of cigarette smoking (packs-year) | 26.8 ± 26.3 | 32.0 ± 25.1 | 26.7 ± 24.9 | 29.53 ± 24.9 |
| VC(L) | 26.3 ± 8.4 | 19.7 ± 7.4* | 17.2 ± 7.5* | 18.55 ± 7.5 |
| FEV1% pred(%) | 73.0 ± 20.1 | 45.8 ± 27.3* | 46.2 ± 14.8* | 46.0 ± 22.3* |
Data are presented as “mean ± SD” for continuous variables and as number (percent) for categorical variables
*p < 0.01, compared with controls