Table 1 Characteristics of age, gender and smoking status of cases and controls

Gender

Male

339 (73.4)^a

252 (49.1)

Female

123 (26.6)^a

259 (50.9)

Age range (yr)

   <60

395 (85.5)^b

422 (82.6)

   ≥60

67 (14.5)^b

89 (17.4)

Mean age in years (S. D.)

45.9 (12.2)

45.7 (15.6)

Smoking status ^a

   No

164 (35.5)^c

353 (69.1)

   Yes

298 (64.5)^c

158 (30.9)

Pack-years smoked

   <20

103 (34.6)^d

70 (44.3)

   ≥20

195 (65.4)^d

88 (55.7)

Mean pack-years smoked (S.D.)

16.1 (17.2)

22.8 (17.3)

Median pack-years smoked (S.D.)

20 (15.6)

20 (17.3)