Table 1 Basic characteristics of study participants

Age (years, Mean ± SD)

51.65 ± 14.43

50.59 ± 14.39

0.242^a

  > 51

281 (55.6%)

247 (48.2%)

  ≤  51

224 (44.4%)

265 (51.8%)

Gender, n (%)

0.282^b

 Male

284 (56.2%)

305 (59.6%)

 Female

221 (43.8%)

207 (40.4%)

Smoking

0.004^b

 Yes

227 (45.0%)

276 (53.9%)

 No

278 (55.0%)

236 (46.1%)

Clinical staging

 III–IV

199 (39.4%)

–

–

 I–II

69 (13.7%)

–

–

 Missing data

237 (46.9%)

–

–