Table 3. Distribution of selected characteristics in the case-control study population.
| Characteristics | Cases, n (%) | Controls, n (%) | P value |
|---|---|---|---|
| Overall | 627 | 633 | |
| Age (years) | |||
| Mean (±SD) | 58 (±10.4) | 58 (±10.5) | 0.9a |
| ≤40 | 29 (4.6) | 29 (4.6) | |
| 41–50 | 109 (17.4) | 125 (19.7) | |
| 51–60 | 222 (35.4) | 214 (33.8) | 0.748b |
| >60 | 267 (42.6) | 265 (41.9) | |
| Gender | |||
| Female | 185 (29.5) | 184 (29.1) | |
| Male | 442 (70.5) | 449 (70.9) | 0.86b |
| Family historyc | |||
| No | 536 (85.5) | 628 (99.2) | |
| Yes | 91 (14.5) | 5 (0.8) | <0.0001b,d |
| Smoking duration | |||
| Never | 241 (38.4) | 333 (52.6) | |
| ≤20 (years) | 104 (16.6) | 98 (15.5) | <0.0001b,d |
| >20 (years) | 282 (45.0) | 202 (31.9) |
a, for t-test; b, for χ2 test (two-sided); c, family history of cancer; d, statistical significance.