Table 1

Distributions of select characteristics by case-control status

VariableCases (n = 724)Controls (n = 791)
Sex, (%)
 Male479 (66.2)519 (65.6)
 Female245 (33.8)272 (34.4)
Mean age in years (SD)57.0 (10.2)56.6 (8.8)
Smoking status (%)
 Never303 (41.9)a457 (57.8)
 Everb421 (58.1)a334 (42.2)
  <27 pack-years156 (37.1)a188 (56.3)
  ≥27 pack-years265 (62.9)a146 (43.7)
Mean pack-years smoked (SD)34.8 (23.0)a27.4 (16.3)
Histological type (%)
 Squamous cell carcinoma263 (36.3)
 Adenocarcinoma319 (44.1)
 Otherc142 (19.6)
  • a P < 0.0000, compared with controls.

  • b Includes 68 former smokers (26 cases and 42 controls).

  • c Other includes undifferentiated cancer (n = 60), bronchioalveolar carcinoma (n = 27), and small cell carcinoma (n = 55).