Sample characteristics overall and by iron-deficiency anaemia (IDA) and haematochezia analytic cohorts
| IDA cohort | Haematochezia cohort | |||||
| Overall N=239 000 | No IDA N=191 200 | IDA N=47 800 | Overall N=653 740 | No haematochezia N=522 992 | Haematochezia N=130 748 | |
| Follow-up time in years, median (Q1-Q3) | 3.8 (1.7–5.0) | 3.8 (1.8–5.0) | 3.6 (1.6–5.0) | 5.0 (3.1–5.0) | 5.0 (3.1–5.0) | 5.0 (3.0–5.0) |
| Age in years, median (Q1-Q3) | 42 (36–46) | 42 (36–46) | 43 (36–46) | 42 (34–46) | 42 (34–46) | 42 (34–46) |
| Ages <30 | 25 430 (10.6%) | 20 505 (10.7%) | 4925 (10.3%) | 98 575 (15.0%) | 78 875 (15.1%) | 19 700 (15.0%) |
| Ages 30–39 | 62 407 (26.1%) | 50 152 (26.2%) | 12 255 (25.6%) | 162 800 (24.9%) | 130 294 (24.9%) | 32 506 (24.9%) |
| Ages 40–49 | 151 163 (63.2%) | 120 543 (63.0%) | 30 620 (64.1%) | 392 365 (60.0%) | 313 823 (60.0%) | 78 542 (60.1%) |
| Sex | ||||||
| Male | 112 225 (47.0%) | 89 780 (47.0%) | 22 445 (47.0%) | 571 295 (87.4%) | 457 036 (87.4%) | 114 259 (87.4%) |
| Female | 126 775 (53.0%) | 101 420 (53.0%) | 25 355 (53.0%) | 82 445 (12.6%) | 65 956 (12.6%) | 16 489 (12.6%) |
| Race/ethnicity | ||||||
| White | 116 577 (48.8%) | 98 077 (51.3%) | 18 500 (38.7%) | 349 040 (53.4%) | 277 533 (53.1%) | 71 507 (54.7%) |
| Black | 72 569 (30.4%) | 51 852 (27.1%) | 20 717 (43.3%) | 153 210 (23.4%) | 119 185 (22.8%) | 34 025 (26.0%) |
| Hispanic | 16 849 (7.1%) | 13 640 (7.1%) | 3209 (6.7%) | 49 902 (7.6%) | 38 880 (7.4%) | 11 022 (8.4%) |
| Asian/Pacific Islander | 4435 (1.9%) | 3646 (1.9%) | 789 (1.7%) | 4542 (0.7%) | 3565 (0.7%) | 977 (0.8%) |
| American Indian | 1880 (0.8%) | 1456 (0.8%) | 424 (0.9%) | 10 348 (1.6%) | 8170 (1.6%) | 2178 (1.7%) |
| Multiracial/other | 4124 (1.7%) | 3365 (1.8%) | 759 (1.6%) | 12 830 (2.0%) | 10 235 (2.0%) | 2595 (2.0%) |
| Missing | 22 566 (9.4%) | 19 164 (10.0%) | 3402 (7.1%) | 73 868 (11.3%) | 65 424 (12.5%) | 8444 (6.5%) |
| Smoking status | ||||||
| Never | 79 949 (33.5%) | 61 011 (31.9%) | 18 938 (39.6%) | 169 458 (25.9%) | 131 643 (25.2%) | 37 815 (28.9%) |
| Former | 22 569 (9.4%) | 17 700 (9.3%) | 4869 (10.2%) | 58 781 (9.0%) | 44 809 (8.6%) | 13 972 (10.7%) |
| Current | 60 234 (25.2%) | 49 021 (25.6%) | 11 213 (23.5%) | 180 728 (27.6%) | 138 255 (26.4%) | 42 473 (32.5%) |
| Missing | 76 248 (31.9%) | 63 468 (33.2%) | 12 780 (26.7%) | 244 773 (37.4%) | 208 285 (39.8%) | 36 488 (27.9%) |
| Prevalent diabetes | 18 847 (7.9%) | 12 755 (6.7%) | 6092 (12.7%) | 44 390 (6.8%) | 34 071 (6.5%) | 10 319 (7.9%) |
| BMI, median (Q1-Q3) | 28.8 (25.0–33.0) | 28.7 (25.1–32.9) | 28.9 (24.8–33.6) | 29.0 (25.7–32.9) | 28.9 (25.6–32.7) | 29.5 (26.1–33.5) |
| Underweight | 1695 (0.7%) | 1052 (0.6%) | 643 (1.4%) | 2503 (0.4%) | 1890 (0.4%) | 613 (0.5%) |
| Normal | 41 900 (17.5%) | 31 768 (16.6%) | 10 132 (21.2%) | 88 345 (13.5%) | 67 484 (12.9%) | 20 861 (16.0%) |
| Overweight | 58 852 (24.6%) | 46 021 (24.1%) | 12 831 (26.8%) | 161 697 (24.7%) | 121 257 (23.2%) | 40 440 (30.9%) |
| Obese | 73 541 (30.8%) | 55 679 (29.1%) | 17 862 (37.4%) | 189 632 (29.0%) | 136 360 (26.1%) | 53 272 (40.7%) |
| Missing | 63 012 (26.4%) | 56 680 (29.6%) | 6332 (13.2%) | 211 563 (32.4%) | 196 001 (37.5%) | 15 562 (11.9%) |
| Aspirin use | 17 605 (7.4%) | 11 358 (5.9%) | 6247 (13.1%) | 42 446 (6.5%) | 29 457 (5.6%) | 12 989 (9.9%) |
BMI, body mass index; Q, quartile.