Table 1. The characteristics of the study population.
| Case (N = 611) | Control (n = 1062) | ||
| Variables | NO. (%) | NO. (%) | P |
| Gender | 0.475a | ||
| Male | 419(68.6) | 746(70.2) | |
| Female | 192(31.4) | 316(29.8) | |
| Median age | 61.5 | 61.0 | 0.115b |
| ≤61.0 | 322(52.7) | 531(50.0) | 0.287a |
| >61.0 | 289(47.3) | 531(50.0) | |
| Smoking status | <0.001a | ||
| Never-smoker | 279(45.7) | 599(56.4) | |
| Smoker | 324(53.0) | 458(43.1) | |
| Unknown | 8(1.3) | 5(0.5) | |
| Histological type | |||
| NSCLC | 427(69.9) | ||
| Others | 184(30.1) |
a
P value was calculated by the x 2 test;
b
P value was calculated by the t test.
Abbreviations: NSCLC, non-small cell lung cancer.