Distributions of select characteristics by case–control status
| Variable | Patients (n = 1000) | Controls (n = 1270) | p value* | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| n | % | n | (%) | |||||||
| *Two sided χ2 test. †Includes 90 undifferentiated cancers, 90 bronchioalveolar carcinomas, 24 small cell carcinomas (SCC), and 51 mixed cell carcinomas. | ||||||||||
| Sex | 0.535 | |||||||||
| Male | 723 | 72.3 | 933 | 73.5 | ||||||
| Female | 277 | 27.7 | 337 | 26.5 | ||||||
| Age (years) | 0.643 | |||||||||
| ⩽50 | 248 | 24.8 | 327 | 25.8 | ||||||
| 51–60 | 330 | 33.0 | 440 | 34.6 | ||||||
| 61–70 | 320 | 32.0 | 386 | 30.4 | ||||||
| >70 | 102 | 10.2 | 117 | 9.2 | ||||||
| Smoking status | <0.0001 | |||||||||
| Nonsmoker | 350 | 34.5 | 625 | 49.2 | ||||||
| Smoker | 650 | 65.5 | 645 | 50.8 | ||||||
| Smoking level (pack years) | <0.0001 | |||||||||
| ⩽20 | 190 | 29.2 | 305 | 47.3 | ||||||
| >20 | 460 | 70.8 | 340 | 52.7 | ||||||
| Histological type | ||||||||||
| SCC | 448 | 44.8 | ||||||||
| Adenocarcinoma | 297 | 29.7 | ||||||||
| Other† | 255 | 25.5 | ||||||||