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. 2022 May 24;127(4):726–734. doi: 10.1038/s41416-022-01856-w

Table 1.

Main characteristics of gastric cancer cases and controlsa in the Stomach cancer Pooling (StoP) Project consortium.

Cases Controls
N % N %
Total 9438 100.0 20,451 100.0
Study center
  Europe 3750 39.7 7030 34.4
   Greece 1 [24] 110 1.2 100 0.5
   Greece 2 [23] 82 0.9 410 2
   Italy 1 [26] 769 8.1 2081 10.2
   Italy 2 [27] 230 2.4 547 2.7
   Italy 4 [25] 1016 10.8 1159 5.7
   Portugal [30] 692 7.3 1667 8.2
   Russia [29] 450 4.8 611 3
   Spain 2 [34] 401 4.2 455 2.2
Asia 1686 17.9 2789 13.6
   China 1 [5] 266 2.8 533 2.6
   China 2 [41] 206 2.2 415 2
   China 3 [42] 711 7.5 711 3.5
   China 4 [43] 133 1.4 433 2.1
   Iran 1 [40] 217 2.3 394 1.9
   Japan 3 [35] 153 1.6 303 1.5
Americas 4002 42.4 10,632 52.0
   Brazil 1 [38] 226 2.4 226 1.1
   Brazil 2 [37] 93 1 186 0.9
   Brazil 3 [39] 368 3.9 738 3.6
   Canada [28] 1182 12.5 5039 24.6
   Mexico 1 [36] 248 2.6 478 2.3
   USA 1 [32] 132 1.4 132 0.6
   USA 3 [33] 170 1.8 502 2.5
   USA 4 [31] 1583 16.8 3331 16.3
Sex
  Men 6243 66.1 12,185 59.6
  Women 3195 33.9 8266 40.4
Age
  <40 312 3.3 1600 7.8
  40–44 314 3.3 1212 5.9
  45–49 542 5.7 1521 7.4
  50–54 754 8.0 1781 8.7
  55–59 1083 11.5 2214 10.8
  60–64 1450 15.4 2828 13.8
  65–69 1846 19.6 3532 17.3
  70–74 1902 20.1 3408 16.7
  ≥75 1235 13.1 2342 11.5
Socioeconomic status (study-specific)
  Low 4704 50.6 7529 37.3
  Intermediate 3107 33.4 7451 36.9
  High 1478 15.9 5215 25.8
Tobacco smoking
  Never 3736 41.2 9033 45.3
  Former 3100 34.2 6372 32.0
 Current
   Low 547 6.0 1364 6.8
   Intermediate 929 10.3 1812 9.1
   High 744 8.2 1344 6.7
Alcohol drinking (g/day)b
  Never 2602 31.3 5997 32.5
  <1 drink/day 2075 25.0 5964 32.4
  1–3 drinks/day 2387 28.7 4388 23.8
  ≥4 drinks/day 1249 15.0 2069 11.2
Vegetable and fruit intake (study-specific tertiles)c
  Low 2862 31.1 5829 29.3
  Intermediate 3087 33.6 6784 34.2
  High 3250 35.3 7248 36.5
Salt intake (study-specific tertiles)d
  Low 2957 40.4 7202 41.7
  Intermediate 2529 34.6 5675 32.8
  High 1830 25.0 4413 25.5
Family history of gastric cancere
  No 3541 81.6 7220 91.6
  Yes 800 18.4 658 8.3
H. pylori infectionf
  No 754 33.3 1361 31.9
  Yes 1511 66.7 2900 68.1
Type of controlsg
  Hospital-based 3198 33.9 5912 28.9
  Population-based 6240 66.1 14,539 71.1
Study designh
  Case-control 7773 82.4 16,710 81.7
  Nested case-control 1665 17.6 3741 18.3
Subsitei
  Cardia 1607 28.4 20,451 100.0
  Non-cardia 4057 71.6 20,451 100.0
Histological typej
  Intestinal 1897 29.3 20,451 100.0
  Diffuse 1218 18.8 20,451 100.0
  Mixed/unspecified 3368 51.9 20,451 100.0

aFor some variables, the sum does not add to the total because of missing values in age (13 controls), social class (149 cases, 256 controls), tobacco smoking (382 cases, 526 controls), alcohol drinking (281 cases, 889 controls), family history of gastric cancer (1025 controls, 2071 cases), vegetable and fruit intake (106 cases, 157 controls) and salt intake (203 cases, 781 controls), or because the variables were not available for some studies.

bThe studies China 3 [42] and China 4 [43] did not collect data on alcohol drinking.

cThe study China 4 [43] did not collect data on vegetable and fruit intake.

dThe studies Greece 1 [24], Greece 2 [23], China 3 [42] and Italy 4 [25] did not collect data on salt intake.

eThe studies China 1 [5], Canada [28], China 3 [42], Mexico 1 [36], Greece 2 [23] and USA 4 [31] did not collect data on family history of gastric cancer.

fThe studies China 2 [41], Russia [29], Iran 1 [40], China 4 [43], Portugal [30], Mexico 1 [36], Brazil 1 [38], Brazil 2 [37], Japan 3 [35] and Brazil 3 [39] collected data on H. pylori infection. The study Spain 2 [34] was not included because no information on H. pylori infection was available for controls.

gThe studies Italy 4 [25], Canada [28], China 2 [41], Iran 1 [40], China 3 [42], China 4 [43], Portugal [30], Mexico 1 [36] and USA 3 [33] include population-based controls.

hThe studies Greece 2 [23] and USA 4 [31] are nested case-control studies (NCC).

iThe studies China 1 [5], China 2 [41], China 3 [42] and China 4 [43] did not collect data on cancer subsite.

jThe studies Italy 1 [26], China 1 [5], Greece 1 [24], China 2 [41], China 3 [42], China 4 [43], Japan 3 [35] and Greece 2 [23] did not collect data on histological type.