Table 1.
Characteristics of participants with a register-based diagnosis of inflammatory bowel disease in the ABIS cohort
| Characteristic | Overall, N = 16,223 | No IBD, n = 16,110 | IBDa, n = 113 | CD, n = 40 | UC, n = 57 |
|---|---|---|---|---|---|
| Sex | |||||
| Female | 7,821 (48.2%) | 7,769 (48.2%) | 52 (46.0%) | 14 (35.0%) | 27 (47.4%) |
| Male | 8,402 (51.8%) | 8,341 (51.8%) | 61 (54.0%) | 26 (65.0%) | 30 (52.6%) |
| Birth year | |||||
| 1997 | 1,668 (10.3%) | 1,657 (10.3%) | 11 (9.7%) | 3 (7.5%) | 6 (10.5%) |
| 1998 | 8,602 (53.0%) | 8,536 (53.0%) | 66 (58.4%) | 25 (62.5%) | 33 (57.9%) |
| 1999 | 5,953 (36.7%) | 5,917 (36.7%) | 36 (31.9%) | 12 (30.0%) | 18 (31.6%) |
| Age at end of observation/diagnosis (years) | |||||
| Mean (SD) | 22.2 (1.0) | 22.2 (0.9) | 16.9 (3.7) | 16.5 (3.3) | 17.0 (4.1) |
| Median (IQR) | 22.3 (21.7, 22.7) | 22.3 (21.8, 22.7) | 17.9 (15.1, 19.5) | 16.4 (14.3, 18.5) | 18.1 (15.7, 19.7) |
| Range | 0.1, 23.5 | 0.1, 23.5 | 2.6, 22.7 | 4.7, 22.4 | 2.6, 22.7 |
| Maternal IBD | |||||
| Yes | 99 (0.6%) | 95 (0.6%) | 4 (3.5%) | 2 (5.0%) | 2 (3.5%) |
| Paternal IBD | |||||
| Yes | 98 (0.6%) | 97 (0.6%) | 1 (0.9%) | 1 (2.5%) | 0 (0.0%) |
| Maternal education level | |||||
| 0–9 years | 1,358 (8.6%) | 1,346 (8.6%) | 12 (10.7%) | 5 (12.5%) | 7 (12.5%) |
| 10–12 years | 8,813 (55.6%) | 8,749 (55.6%) | 64 (57.1%) | 20 (50.0%) | 33 (58.9%) |
| ≥ 13 years | 5,669 (35.8%) | 5,633 (35.8%) | 36 (32.1%) | 15 (37.5%) | 16 (28.6%) |
| Missing data | 383 | 382 | 1 | 0 | 1 |
| Delivery mode | |||||
| Vaginal | 13,040 (80.4%) | 12,949 (80.4%) | 91 (80.5%) | 34 (85.0%) | 45 (78.9%) |
| Caesarean | 1,866 (11.5%) | 1,851 (11.5%) | 15 (13.3%) | 4 (10.0%) | 8 (14.0%) |
| Missing data | 1317 (8.1%) | 1310 (8.1%) | 7 (6.2%) | 2 (5.0%) | 4 (7.0%) |
| Maternal age at delivery (years) | |||||
| Mean (SD) | 29.0 (4.6) | 29.0 (4.6) | 29.3 (4.6) | 29.4 (5.2) | 28.8 (4.2) |
| Missing data | 250 | 250 | 0 | 0 | 0 |
| Gestational age (weeks) | |||||
| Mean (SD) | 39.7 (1.8) | 39.7 (1.8) | 39.6 (1.7) | 39.7 (1.8) | 39.7 (1.6) |
| Missing data | 333 | 331 | 2 | 0 | 1 |
| Small for gestational ageb | |||||
| Small | 292 (1.9%) | 288 (1.9%) | 4 (3.6%) | 2 (5.1%) | 1 (1.8%) |
| Missing data | 732 | 729 | 3 | 1 | 1 |
aInclude data on patients with undefined inflammatory bowel disease (IBD), where a mix of IBD codes did not allow us to distinguish Crohn's disease (CD) from ulcerative colitis (UC)
bSmall for gestational age equalled < 2 standard deviations (SD) of mean weight for age. ABIS All Babies in Southeast Sweden, IQR interquartile range