Table 1. Demographic characteristics of the subjects in this study.
| Variables | Case (n = 1,200) | Control (n = 1,253) | P-value |
|---|---|---|---|
| Age (Mean ± S.D.)a | 60.99 ± 10.20 | 61.23 ± 10.82 | 0.569 |
| <60 | 533 (44.42) | 549 (43.81) | 0.764 |
| ≥60 | 667 (55.58) | 704(56.19) | |
| Gender | |||
| Male | 849 (70.75) | 853 (68.08) | 0.151 |
| Female | 351 (29.25) | 400 (31.92) | |
| Smoking Status | <0.001 | ||
| Current | 569 (47.42) | 553(44.13) | |
| Former | 167 (13.92) | 53 (4.23) | |
| Never | 464 (38.66) | 647 (51.64) | |
| Smoking Levels (Mean ± S.D.)a | 41.33 ± 27.95 | 29.94 ± 20.61 | <0.001 |
| ≤25 (Pack-years) | 227 (30.84) | 290 (47.85) | <0.001 |
| >25 (Pack-years) | 509 (69.16) | 316 (52.15) | |
| Histology | |||
| Squamous cell carcinoma | 427 (35.58) | ||
| Adenocarcinoma | 773 (64.42) | ||
aMean ± standard deviation in case and control groups respectively.