Table 1

Baseline characteristics of study population

CharacteristicInvited to screening groupControl group (n=299 483)
Screened (n=113 340)Not screened (n=224 677)Total (n=338 017)
Sex (%)
 Men51 080 (45.07)115 879 (51.58)166 959 (49.39)148 182 (49.48)
 Women62 260 (54.93)108 798 (48.42)171 058 (50.61)151 301 (50.52)
Age at entry (%)
 40–49 year45 636 (40.26)103 947 (46.27)149 583 (44.25)135 364 (45.20)
 50–59 year43 756 (38.61)75 252 (33.49)119 008 (35.21)112 468 (37.55)
 60–69 year23 948 (21.13)45 478 (20.24)69 426 (20.54)51 651 (17.25)
Area (%)
 Cixian22 135 (19.53)49 788 (22.16)71 923 (21.28)19 384 (6.47)
 Feicheng23 470 (20.71)18 718 (8.33)42 188 (12.48)58 106 (19.40)
 Linzhou19 805 (17.47)38 333 (17.06)58 138 (17.2)35 757 (11.94)
 Yancheng12 460 (10.99)41 081 (18.28)53 541 (15.84)66 525 (22.21)
 Yanting22 702 (20.03)43 500 (19.36)66 202 (19.59)33 325 (11.13)
 Yangzhong12 768 (11.27)33 257 (14.80)46 025 (13.62)86 386 (28.85)
Person-years of follow-up*657 3491 394 6262 051 9752 915 581
  • *Person-years are follow-up from cohort entry date to the date of last follow-up based on the analyses for upper gastrointestinal cancer incidence.