| Characteristic | Total | Odds Ratio (95% CI) | p-Value | |
| Age | Per year increase | 8423 | 0.99 (0.99 - 0.99) | <0.0001 |
| Histology | Squamous (reference) | 1721 | . | <0.0001 |
| Adenocarcinoma | 5930 | 5.05 (4.38 - 5.82) | ||
| Other | 523 | 1.52 (1.19 - 1.94) | ||
| Adenosquamous | 178 | 3.55 (2.53 - 4.99) | ||
| Bronchioloalveolar carcinoma | 71 | 5.56 (3.36 - 9.22) | ||
| Practice Region | South (reference) | 5288 | . | 0.0013 |
| West | 1767 | 0.95 (0.84 - 1.07) | ||
| Midwest | 880 | 1.33 (1.13 - 1.57) | ||
| Northeast | 488 | 0.93 (0.75 - 1.15) |