Table 1.
Distributions of select characteristics among lungcancer cases and cancer-free controls
| Characteristics | Cases (n = 1009) | Controls (n = 1127) | P* | ||
|---|---|---|---|---|---|
| No. | % | No. | % | ||
| Age (years) | 0.643 | ||||
| ≤60 | 519 | 51.4 | 591 | 52.4 | |
| >60 | 490 | 48.6 | 536 | 47.6 | |
| Sex | 0.772 | ||||
| Male | 754 | 74.7 | 836 | 74.2 | |
| Female | 255 | 25.2 | 291 | 25.8 | |
| Smoking status | < 0.001 | ||||
| Nonsmoker | 357 | 35.4 | 625 | 55.5 | |
| Smoker | 652 | 64.6 | 502 | 44.5 | |
| Smoking level† | < 0.001 | ||||
| ≤25 pack-years | 204 | 31.3 | 240 | 47.8 | |
| >25 pack-years | 448 | 68.7 | 262 | 52.2 | |
| Histological type§ | |||||
| SCC | 310 | 30.7 | |||
| AC | 588 | 58.3 | |||
| Other | 111 | 11.0 | |||
*
Two-sided χ2 test.
†
Categorized by using the 50th percentile of pack-years (cigarettes per day/20 × years smoked) of the control subjects as the cutoff points.
§
SCC, squamous cell carcinoma; AC, adenocarcinoma; Other, includes large cell, mixed cell and undifferentiated carcinoma.