Table 1. Characteristics of the study population.
| Characteristic | Controls (n = 504) (%) | Cases (n = 442) (%) | p-Value |
| Sex | |||
| Male | 392 (77.78) | 358 (81.00) | 0.223a |
| Female | 112 (22.22) | 84 (19.00) | |
| Age at diagnosis (years) | |||
| <39 | 31 (6.15) | 24 (5.43) | 0.599a |
| 40–49 | 87 (17.26) | 65 (14.71) | |
| 50–59 | 162 (32.14) | 146 (33.03) | |
| 60–69 | 131 (25.99) | 132 (29.86) | |
| >70 | 93 (18.45) | 75 (16.97) | |
| Mean age ± SD | 58.43±10.52 | 58.78±11.18 | 0.622b |
| Histology | |||
| Adenocarcinoma | - | 165 (37.33) | - |
| Squamous cell carcinoma | - | 115 (26.02) | |
| Other non-small cell carcinoma | - | 99 (22.40) | |
| Small cell carcinoma | - | 63 (14.25) | |
| Pack-years of smokingc | |||
| 0–30 | 447 (88.69) | 255 (57.69) | <0.001a |
| >30 | 57 (11.31) | 187 (42.31) | |
| Mean pack-year ± SD | 8.63±18.43 | 23.95±21.90 | <0.001b |
| Mean pack-year ± SDd | 11.10±20.23 | 29.39±20.71 | <0.001b |
a
χ 2-Test or Fisher's exact test.
b
t-Test.
c
The median number of pack years of combined cases and controls were utilized as the cut-point.
d
restricted to males only.