Table 1.
Baseline characteristics of colorectal cancer cases and controls
| Controls, N (%) |
||||
|---|---|---|---|---|
| Variables | Cases, N (%) (n = 5847) |
Total controls (n = 4970) |
Population controls (n = 4243) |
Spouse controls (n =727) |
| Age at recruitment, years | ||||
| Mean (SD) | 55.2 (11.8) | 57.5 (11.6) | 58.4 (11.7) | 52.5 (10) |
| Median (range) | 54 | 59 | 60 | 52 |
|
| ||||
| Sex | ||||
| Female | 2959 (50.6) | 2630 (52.9) | 2191 (51.6) | 439 (60.4) |
| Male | 2888 (49.4) | 2340 (47.1) | 2052 (48.4) | 288 (39.6) |
|
| ||||
| Recruitment centre | ||||
| Cancer Care Ontario | 2098 (35.9) | 1920 (38.6) | 1920 (45.2) | 0 |
| University of Melbourne | 807 (13.8) | 719 (14.5) | 270 (6.4) | 449 (61.8) |
| Mayo Clinic | 623 (10.7) | 278 (5.6) | 0 | 278 (38.2) |
| Fred Hutchinson Seattle | 2319 (39.6) | 2053 (41.3) | 2053 (48.4) | 0 |
|
| ||||
| Cholecystectomy | ||||
| Yes | 521 (8.9) | 555 (11.2) | 504 (11.9) | 51 (7) |
| No | 5326 (91.1) | 4415 (88.8) | 3739 (88.1) | 676 (93) |
|
| ||||
| Family history of CRC (first-degree relative) |
||||
| Yes (at least 1 affected) | 1248 (21.3) | 529 (10.6) | 460 (10.8) | 69 (9.5) |
| No | 4599 (78.7) | 4441 (89.4) | 3783 (89.2) | 658 (90.5) |
|
| ||||
| Body mass index, recent (kg/m2) | ||||
| Underweight (<18.5) | 86 (1.5) | 57 (1.2) | 50 (1.2) | 7 (1) |
| Normal (18.5-24.9) | 2010 (34.4) | 2020 (40.6) | 1732 (40.8) | 288 (39.6) |
| Overweight (25.0-29.9) | 2214 (37.9) | 1849 (37.2) | 1626 (38.3) | 223 (30.7) |
| Obese (≥30) | 1413 (24.2) | 922 (18.5) | 789 (18.6) | 133 (18.3) |
| Missing | 124 (2) | 122 (2.5) | 46 (1.1) | 76 (10.4) |
|
| ||||
| Body mass index at age 20 years (kg/m2) |
||||
| Underweight (<18.5) | 423 (7.2) | 439 (8.8) | 373 (8.8) | 66 (9.1) |
| Normal (18.5-24.9) | 3989 (68.2) | 3595 (72.3) | 3121 (73.6) | 474 (65.2) |
| Overweight (25.0-29.9) | 969 (16.6) | 638 (12.8) | 549 (12.9) | 89 (12.2) |
| Obese (≥30) | 230 (3.9) | 112 (2.3) | 95 (2.2) | 17 (2.3) |
| Missing | 236 (4.1) | 186 (3.8) | 105 (2.5) | 81 (11.2) |
|
| ||||
| Cigarette smoking | ||||
| Current^^ | 662 (11.3) | 638 (12.8) | 537 (12.7) | 101 (13.9) |
| Former^ | 2635 (45.1) | 2056 (41.4) | 1788 (42.1) | 268 (36.9) |
| Never | 2511 (43) | 2250 (45.3) | 1901 (44.8) | 349 (48) |
| Missing | 39 (0.6) | 256 (0.5) | 17 (0.4) | 9 (1.2) |
|
| ||||
| Education | ||||
| Primary school | 107 (1.8) | 91 (1.8) | 79 (1.9) | 12 (1.6) |
| Secondary school | 821 (14) | 658 (13.2) | 541 (12.7) | 117 (16.1) |
| High/Senior secondary school | 1310 (22.4) | 958 (19.3) | 789 (18.6) | 169 (23.3) |
| Vocational education or training | 583 (10) | 466 (9.4) | 352 (8.3) | 114 (15.7) |
| University without degree | 1330 (22.8) | 1089 (21.9) | 1025 (24.2) | 64 (8.8) |
| University graduation or higher | 1649 (28.2) | 1618 (3.6) | 1444 (34) | 174 (23.9) |
| Missing | 47 (0.8) | 90 (1.8) | 13 (0.3) | 77 (10.6) |
|
| ||||
| Annual household Income | ||||
| ≤ $15,000 | 319 (5.5) | 190 (3.8) | 186 (4.4) | 4 (0.5) |
| $15,000-30,000 | 777 (13.3) | 572 (11.5) | 538 (12.7) | 34 (4.7) |
| $30,000-45,000 | 1031 (17.6) | 925 (18.6) | 864 (20.4) | 61 (8.4) |
| $45,000-70,000 | 1068 (18.3) | 933 (18.8) | 870 (20.5) | 63 (8.6) |
| ≥ $70,000 | 1026 (17.5) | 876 (17.6) | 790 (18.6) | 86 (11.8) |
| Refused to answer | 144 (2.5) | 147 (3) | 140 (3.3) | 7 (1) |
| Missing | 1482 (25.3) | 1327 (26.7) | 855 (20.1) | 472 (64.9) |
|
| ||||
| Race | ||||
| Caucasian | 5206 89) | 4592 (92.4) | 3944 (93) | 648 (89.1) |
| Other | 514 (8.8) | 276 (5.6) | 254 (6) | 22 (3) |
| Missing | 127 (2.2) | 102 (2) | 45 (1) | 57 (7.9) |
|
| ||||
| Diabetes mellitus | ||||
| Yes | 468 (8) | 376 (7.6) | 340 (8) | 36 (5) |
| No | 5360 (91.7) | 4581 (92.2) | 3895 (91.8) | 686 (94.3) |
| Missing | 19 (0.3) | 13 (0.2) | 8 (0.2) | 5 (0.7) |
|
| ||||
| Aspirin intake** | ||||
| ≥5years | 471 (8.1) | 623 (12.5) | 577 (13.6) | 46 (6.3) |
| <5years | 884 (15.1) | 888 (17.9) | 806 (19) | 82 (11.3) |
| Never | 4231 (72.4) | 3263 (65.7) | 2705 63.8) | 558 (76.8) |
| Missing | 261 (4.4) | 196 (3.9) | 155 (3.7) | 41 (5.6) |
|
| ||||
| Ibuprofen intake** | ||||
| ≥5years | 172 (3) | 182 (3.7) | 155 (3.7) | 27 (3.7) |
| <5years | 685 (11.7) | 719 (14.5) | 642 (15.1) | 77 (10.6) |
| Never | 4756 (81.3) | 3904 (78.5) | 3332 (78.5) | 572 (78.7) |
| Missing | 234 (4) | 165 (3.3) | 114 (2.7) | 51 (7) |
|
| ||||
| Multivitamin intake** | ||||
| ≥5years | 1553 (26.6) | 1463 (29.4) | 1361 (32.1) | 102 (14) |
| <5years | 1102 18.8) | 859 (17.3) | 752 (17.7) | 107 (14.7) |
| Never | 2845 (48.7) | 2434 (49) | 1975 (46.5) | 459 (63.2) |
| Missing | 347 (5.9) | 214 (4.3) | 155 (3.7) | 59 (8.1) |
|
| ||||
| Regular physical activity* | ||||
| Yes | 5023 (85.9) | 4287 (86.3) | 3668 (86.5) | 619 (85.1) |
| No | 90 (1.5) | 108 (2.2) | 89 (2.1) | 19 (2.6) |
| Missing | 734 (12.6) | 575 (11.5) | 486 (11.4) | 89 (12.2) |
|
| ||||
| Alcohol consumption (standard drink per day) ^^^ |
||||
| Mean (SD) | 1.2 (2.3) | 1 (2.1) | 1.1 (2.1) | 0.9 (1.6) |
| Missing, N | 1684 | 1225 | 1075 | 150 |
|
| ||||
| Red meat consumption (number of serve per day) |
||||
| Mean (SD) | 0.66 (0.63) | 0.58 (0.55) | 0.54 (0.53) | 0.81 (0.66) |
| Missing, N | 187 | 222 | 149 | 73 |
|
| ||||
| Number of live birth # | ||||
| 0 | 374 (12.6) | 269 (10.2) | 230 (10.5) | 39 (8.9) |
| 1 | 349 (11.8) | 275 (10.4) | 230 (10.5) | 45 (10.3) |
| 2 | 909 (30.7) | 830 (31.6) | 656 (29.9) | 174 (39.6) |
| 3 | 605 (20.5) | 538 (20.5) | 440 (20.1) | 98 (22.3) |
| ≥4 | 516 (17.4) | 412 (15.7) | 345 (15.8) | 67 (15.3) |
| Missing | 206 (7) | 306 (11.6) | 290 (13.2) | 16 (3.6) |
|
| ||||
| Hormonal contraceptives# | ||||
| ≥5 years | 1007 (34) | 939 (35.7) | 719 (32.8) | 220 (50.1) |
| <5 years | 577 (19.5) | 545 (20.7) | 433 (19.8) | 112 (25.5) |
| Never | 1192 (40.3) | 1023 (38.9) | 935 (42.7) | 88 (20.1) |
| Missing | 183 (6.2) | 123 (4.7) | 104 (4.7) | 19 (4.3) |
|
| ||||
| Hormone replacement therapy# | ||||
| Estrogen-only users | 491 (16.6) | 473 (18) | 411 (18.8) | 62 (14.1) |
| Progesterone and estrogen users | 187 (6.3) | 214 (8.1) | 187 (8.5) | 27 (6.2) |
| Never | 1879 (63.5) | 1467 (55.8) | 1221 (55.7) | 246 (56) |
| Missing | 402 (13.6) | 476 (18.1) | 372 (17) | 104 (23.7) |
|
| ||||
| Anatomical location | ||||
| Proximal colon | 1968 (33.6) | __ | __ | __ |
| Distal colon | 1811 (31) | __ | __ | __ |
| Colon unspecified | 81 (1.4) | __ | __ | __ |
| Rectum | 1987 (34) | __ | __ | __ |
|
| ||||
| Tumor MMR status | ||||
| MMR-proficient tumor | 3790 (64.8) | __ | __ | __ |
| MMR-deficient tumor | 631 (10.8) | __ | __ | __ |
| Missing | 1426 (24.4) | __ | __ | __ |
#
Questions asked only for women (2959 cases and 2630 controls)
*
regular physical activity defined as any physical activity for at least 30 minutes per week for at least 3 months
**
at least twice a week for at least 1 month
^
former smokers defined as participants who had smoked at least 1 cigarette per day for at least 3 months and had quit more than 2 years before age at colorectal cancer or age at interview.
^^
current smokers defined as participants who had smoked at least 1 cigarette per day for at least 3 months and continued within 2 years of age at colorectal cancer or age at interview.
^^^
4-oz. glasses of wine, or 12-oz. cans or bottles of beer or hard cider, or 1-oz. servings of sake or liquor (spirits)
MMR, mismatch repair; SD, standard deviation; N, number;__, not relevant