Table 1.
Characteristics of children in MoBa pregnancy cohort and population based-cohort
| MoBa; pregnancy, and until 6 months of age. n (%) | MoBa; until 18 months of age, n (%) | Register-based cohort | |
|---|---|---|---|
| Participants with exposure data | 84 407 (100.0%) | 70 430 (100.0%) | 537 460 (100.0%) |
| Girls | 41 224 (48.8%) | 34 429 (48.9%) | 261 583 (48.7%) |
| Maternal diabetes | 454 (0.5%) | 379 (0.5%) | 6 510 (1.2%)a |
| Maternal educationb | |||
| Low | 29 939 (35.5%) | 23 983 (34.1%) | 87 878 (16.4%) |
| Medium | 34 887 (41.3%) | 29 648 (42.1%) | 153 954 (28.6%) |
| High | 19 226 (22.8%) | 16 528 (23.5%) | 274 010 (51.0%) |
| Missing | 355 (0.4%) | 271 (0.4%) | 21 618 (4.0%) |
| Maternal smoking in pregnancy | |||
| No | 76 351 (90.5%) | 64 185 (91.1%) | 385 688 (71.8%) |
| Yes | 6747 (8.0%) | 5232 (7.4%) | 61 524 (11.5%) |
| Missing | 1309 (1.6%) | 1013 (1.4%) | 90 248 (16.8%) |
| Maternal parity | |||
| 0 | 39 528 (46.8%) | 33 592 (47.7%) | 226 465 (42.1%) |
| 1 | 29 318 (34.7%) | 24 047 (34.1%) | 191 902 (35.7%) |
| ≥2 | 15 561 (18.4%) | 12 791 (18.2%) | 119 093 (22.2%) |
| Maternal pre-pregnancy BMI | |||
| <25 | 56 602 (67.1%) | 47 566 (67.5%) | – |
| 25-29.9 | 17 968 (21.3%) | 14 898 (21.2%) | – |
| ≥30 | 7662 (9.1%) | 6250 (8.9%) | – |
| Missing | 2175 (2.6%) | 1716 (2.4%) | 537 460 (100%)c |
| Birthweight (grams) | |||
| <2500 g | 3756 (4.4%) | 3154 (4.5%) | 26 140 (4.9%) |
| 2500-3499 g | 32 108 (38.0%) | 26 847 (38.1%) | 227 094 (42.3%) |
| 3500-4499 g | 44 795 (53.1%) | 37 315 (53.0%) | 265 635 (49.4%) |
| ≥4500 g | 3748 (4.4%) | 3114 (4.4%) | 18 591 (3.5%) |
| Maternal age (years) | |||
| ≤24 | 8487 (10.1%) | 6541 (9.3%) | 88 739 (16.5%) |
| 25-34 | 61 114 (72.4%) | 51 379 (73.0%) | 346 882 (64.5%) |
| ≥35 | 14 806 (17.5%) | 12 510 (17.8%) | 101 839 (19.0%) |
| Gestational age | |||
| <37 weeks | 4774 (5.7%) | 3981 (5.7%) | 35 397 (6.6%) |
| ≥37 weeks | 79 276 (93.9%) | 66 149 (93.9%) | 498 263 (92.7%) |
| Missing | 357 (0.4%) | 300 (0.4%) | 3800 (0.7%) |
| Caesarean section | 12 271 (14.5%) | 10 172 (14.4%) | 90 128 (16.8%) |
| Breastfeeding | – | – | |
| Never | 945 (1.1%) | 778 (1.1%) | – |
| Yes | 83 462 (98.9%) | 69 652 (98.9%) | – |
| Missing | – | – | 537 460 (100%)c |
| Child age at end of follow-up among non-cases, median (range) | 12.3 (8.4-17.9) | 12.3 (8.4-17.9) | 6.4 (2.0–11.0) |
a
In the register-based cohort this is defined as maternal insulin use, which would include gestational diabetes and type 2 diabetes.
b
Characterized as: ≤12 years, 13–15 years, ≥16 years in the MoBa cohort; and 9 years, 10–12 years, ≥13 years in the register cohort. This is maternal education at ∼week 18 of pregnancy in the MoBa cohort, and highest attained education in the register-based cohort. This is due to differences in how the data are provided from Statistics Norway and how the questions are asked in the MoBa questionnaires.
c
Not available in the register-based cohort.