Table 1.

Selected characteristics of subjects by case-control status

Selected characteristicsControls
Biliary tract cancers
Biliary stones*
Gallbladder
Bile duct
Ampulla of Vater
Gallbladder
Bile duct
n (%)n (%)n (%)n (%)n (%)n (%)
Total786 (100.0)236 (100.0)127 (100.0)47 (100.0)670 (100.0)221 (100.0)
Sex
    Male305 (38.8)65 (27.4)76 (59.8)24 (51.1)223 (33.3)104 (47.1)
    Female481 (61.2)172 (72.6)§51 (40.2)§23 (48.9)447 (66.7)§117 (52.9)
Age at interview (y)
    <54107 (13.6)32 (13.5)18 (14.2)4 (8.5)213 (31.8)53 (24.0)
    55-64224 (28.5)62 (26.2)32 (25.2)9 (19.2)196 (27.8)66 (29.9)
    ≥65455 (57.9)143 (60.3)77 (60.6)34 (72.3)271 (40.4)§102 (46.1)§
Body mass index (kg/m2)
    <18.566 (8.4)11 (4.7)6 (4.7)1 (2.1)15 (6.8)2 (2.7)
    18.5-22.9325 (41.4)79 (33.5)57 (44.9)20 (42.6)74 (33.5)31 (41.9)
    23.0-24.9166 (21.2)47 (19.9)33 (26.0)11 (23.4)51 (23.1)15 (20.3)
    ≥25.0228 (29.0)99 (41.9)§31 (24.4)15 (31.9)81 (36.6)§26 (35.1)§
Ever smoked cigarettes regularly
    No549 (69.8)172 (72.9)71 (55.9)27 (57.5)510 (76.1)141 (63.8)
    Yes237 (30.2)64 (27.1)56 (44.1)§20 (42.5)160 (23.9)§80 (36.2)
Ever drink alcohol regularly
    No624 (79.4)201 (84.8)85 (66.9)35 (74.5)569 (84.9)180 (81.8)
    Yes162 (20.6)36 (15.2)42 (33.1)§12 (25.5)101 (15.1)§40 (18.2)
Gallstone status
    No592 (75.3)36 (15.2)41 (32.3)19 (40.4)
    Yes194 (24.7)201 (84.8)§86 (67.7)§28 (59.6)§670 (100.0)221(100.0)
  • NOTE: The total number of subjects in some columns may vary across variables because of missing values.

  • * Biliary stone cases compared with controls without stones (n = 592).

  • Gallbladder cancer cases compared with controls with a gallbladder (n = 737). Controls with a history of cholecystectomy were excluded.

  • Bile duct and ampulla of Vater cancer cases compared with all controls (n = 786).

  • § P < 0.05 χ2 test for difference between cases and controls.

  • Body mass index = weight/height2. Categories are based on WHO classification for Asians.

  • Ever smoked cigarettes consecutively for at least 6 mo.