Table 3. Distribution of selected variables between the CWP cases and controls.
| Variables | Case (n = 508) |
Control (n = 526) |
P-value |
| n (%) | n (%) | ||
| Age(y) | 69.47 ± 9.70 | 65.95 ± 6.58 | < 0.001 |
| Exposure period(y) | 26.98 ± 8.68 | 27.20 ± 7.19 | 0.664 |
| Work type | |||
| Tunnel/Coal mining | 489(96.26) | 507(96.39) | 0.616 |
| Transport | 9(1.77) | 12(2.28) | |
| Others | 10(1.97) | 7(1.33) | |
| Smoking status | 0.123 | ||
| Never | 289(56.89) | 324(61.60) | |
| Ever | 219(43.11) | 202(38.40) | |
| Smoking cessation | 111(21.85) | 28(5.32) | < 0.001 |
| Pack-years smoked | |||
| 0 | 288(56.69) | 322(61.22) | < 0.001 |
| 0-20 | 153(30.12) | 77(14.66) | |
| >20 | 67(13.19) | 127(24.14) | |
| Stage | |||
| I | 237(46.65) | ||
| II | 216(42.52) | ||
| III | 55(10.83) | ||
Data are presented as mean±SD or n (%).