Table 1 Baseline characteristics of included participants by diabetes status
| Â | Normal | DM | P-value (DM vs. normal) | T1DM | T2DM | P-value (T2DM vs. T1DM) |
|---|---|---|---|---|---|---|
Overall | 93,560 | 9356 | Â | 8470 | 886 | Â |
Birthweight, g, mean ± SD | ||||||
 Mean ± SD | 3448.8 ± 632.8 | 3447.9 ± 669.9 | 0.900 | 3462.4 ± 667.3 | 3309.5 ± 679.3 |  < 0.001 |
 Median (P25–P75) | 3500.0 (3100.0–3830.0) | 3500.0 (3100.0–3850.0) | 0.709 | 3500.0 (3100.0–3850.0) | 3350.0 (3000.0–3740.0) |  |
 Mean rank | 51,456.2 | 51,481.5 |  | 4740.1 | 4089.9 |  |
Birth weight categories, n (%) |  |  | 0.001 |  |  |  < 0.001 |
 Normal | 72,166 (77.1) | 7100 (75.9) |  | 6419 (75.8) | 681 (76.9) |  |
 Low | 4746 (5.1) | 548 (5.9) |  | 469 (5.5) | 79 (8.9) |  |
 High | 15,928 (17.0) | 1653 (17.7) |  | 1529 (18.1) | 124 (14.0) |  |
 Unknown | 720 (0.8) | 55 (0.5) |  | 53 (0.6) | 2 (0.2) |  |
Gestational age, weeks | ||||||
 Mean ± SD | 39.4 ± 2.0 | 39.2 ± 2.2 |  < 0.001 | 39.3 ± 2.1 | 39.0 ± 2.3 | 0.005 |
 Median (P25–P75) | 40.0 (39.0–41.0) | 40.0 (38.0–40.0) |  < 0.001 | 40.0 (38.0–40.0) | 40.0 (38.0–40.0) | 0.033 |
 Mean rank | 51,729.4 | 48,749.6 |  | 4677.9 | 4684.0 |  |
Preterm birth, n (%) |  |  |  < 0.001 |  |  |  < 0.001 |
 Yes | 5034 (5.4) | 637 (6.8) |  | 556 (6.6) | 81 (9.1) |  |
 No | 83,211 (88.9) | 8203 (87.7) |  | 7479 (88.3) | 724 (81.8) |  |
 Unknown | 5315 (5.7) | 516 (5.5) |  | 435 (5.1) | 81 (9.1) |  |
Age at follow-up, years | ||||||
 Mean ± SD | 23.79 ± 9.28 | 23.49 ± 9.17 |  < 0.003 | 22.94 ± 9.16 | 28.80 ± 7.31 |  < 0.001 |
 Median (P25–P75) | 23.0 (17.0–31.0) | 23.0 (17.0–30.0) | 0.005 | 22.0 (16.0–29.0) | 29.0 (24.0–34.0) |  < 0.001 |
 Mean rank | 51,541.5 | 50,628.2 |  | 4508.5 | 6303.8 |  |
Age at baseline, n (%) | Â | Â | 1.000 | Â | Â | Â |
 0–5 years | 21,840 (23.3) | 2184 (23.3) |  | 2017 (23.8) | 167 (18.8) |  |
 6–12 years | 43,210 (46.2) | 4321 (46.2) |  | 4083 (48.2) | 238 (26.9) |  |
 13–17 years | 28,510 (30.5) | 2851 (30.5) |  | 2370 (28.0) | 481 (54.3) |  |
Duration of diabetes, years, median (P25–P75) | – | 12.26 (6.23–19.59) |  | 11.99 (5.87–19.20) | 14.57 (8.95–26.27) |  < 0.001 |
 Mean rank | – | – |  | 4582.1 | 5600.2 |  |
Calendar year, n (%) |  |  | 1.000 |  |  |  < 0.001 |
 1977–1985 | 18,380 (19.6) | 1838 (19.6) |  | 1544 (18.2) | 294 (33.2) |  |
 1986–1995 | 30,650 (32.8) | 3065 (32.8) |  | 2638 (31.1) | 427 (48.2) |  |
 1996–2016 | 44,530 (47.6) | 4453 (47.6) |  | 4288 (51.7) | 165 (18.6) |  |
Sex, n (%) |  |  | 1.000 |  |  |  < 0.001 |
 Male | 48,850 (52.2) | 4885 (52.2) |  | 4528 (53.5) | 357 (40.4) |  |
 Female | 44,710 (47.8) | 4471 (47.8) |  | 3942 (46.5) | 529 (59.7) |  |
Parity, n (%) | Â | Â | 0.134 | Â | Â | 0.233 |
 1 | 41,463 (44.3) | 4066 (43.5) |  | 3675 (43.4) | 391 (44.1) |  |
 2 | 35,013 (37.4) | 3512 (37.5) |  | 3200 (37.8) | 312 (35.2) |  |
 ≥ 3 | 17,084 (18.3) | 1778 (19.0) |  | 1595 (18.8) | 183 (20.7) |  |
Singleton status, n (%) | Â | Â | 0.641 | Â | Â | 0.051 |
 Yes | 90,622 (96.9) | 9071 (97.0) |  | 8202 (96.8) | 869 (98.1) |  |
 No | 2938 (3.1) | 285 (3.0) |  | 268 (3.2) | 17 (1.9) |  |
Paternal education level, n (%) |  |  |  < 0.001 |  |  |  < 0.001 |
 0–9 years | 21,758 (23.3) | 2202 (24.6) |  | 2017 (23.8) | 285 (32.2) |  |
 10–14 years | 49,820 (53.2) | 5044 (53.9) |  | 4583 (54.1) | 461 (52.0) |  |
 ≥ 15 years | 18,249 (19.5) | 1697 (18.1) |  | 1596 (18.8) | 101 (11.4) |  |
 Unknown | 3733 (4.0) | 313 (3.4) |  | 274 (3.2) | 39 (4.4) |  |
Maternal education level, n (%) |  |  |  < 0.001 |  |  |  < 0.001 |
 0–9 years | 26,556 (28.4) | 2790 (29.8) |  | 2408 (28.4) | 382 (43.1) |  |
 10–14 years | 41,646 (44.5) | 4195 (44.8) |  | 3848 (45.4) | 347 (39.2) |  |
  ≥ 15 years | 24,217 (25.9) | 2287 (24.4) |  | 2142 (25.3) | 145 (16.4) |  |
 Unknown | 1141 (1.2) | 89 (0.9) |  | 72 (0.9) | 12 (1.4) |  |
Residence, n (%) |  |  | 0.004 |  |  |  < 0.001 |
 Copenhagen | 9665 (10.3) | 877 (9.4) |  | 759 (9.0) | 118 (13.3) |  |
 Cities with 100,000 or more inhabitants | 11,903 (12.7) | 1149 (12.3) |  | 1052 (12.4) | 97 (10.9) |  |
 Others | 71,992 (76.9) | 7330 (78.3) |  | 6659 (78.6) | 671 (75.8) |  |
Maternal marital status, n (%) | Â | Â | 0.089 | Â | Â | 0.002 |
 Unmarried | 40,985 (43.8) | 4054 (43.3) |  | 3714 (43.8) | 340 (38.4) |  |
 Married | 52,535 (56.2) | 5302 (56.7) |  | 4756 (56.2) | 546 (61.6) |  |
 Unknown | 40 (0.0) | 0 (0.0) |  | 0 | 0 |  |
Maternal history of diabetes before childbirth, n (%) |  |  |  < 0.001 |  |  |  < 0.001 |
 Yes | 1412 (1.5) | 449 (4.8) |  | 376 (4.4) | 73 (8.2) |  |
 No | 93,048 (98.5) | 8907 (95.2) |  | 8094 (95.6) | 813 (91.8) |  |
Paternal history of diabetes before childbirth, n (%) |  |  |  < 0.001 |  |  | 0.008 |
 Yes | 558 (0.6) | 423 (4.5) |  | 399 (4.7) | 24 (2.7) |  |
 No | 93,002 (99.4) | 8933 (95.5) |  | 8071 (95.3) | 862 (97.3) |  |
Maternal age at childbirth (years) |  |  | 0.572 |  |  |  < 0.001 |
 < 20 | 2333 (2.5) | 217 (2.3) |  | 181 (2.1) | 36 (4.1) |  |
 20–24 | 17,373 (18.6) | 1700 (18.2) |  | 1481 (17.5) | 219 (24.7) |  |
 25–29 | 34,975 (37.4) | 3501 (37.4) |  | 3171 (37.4) | 330 (37.3) |  |
 30–34 | 27,325 (29.2) | 2790 (29.8) |  | 2584 (30.5) | 206 (23.3) |  |
 ≥ 35 | 11,554 (12.4) | 1148 (12.3) |  | 1053 (12.4) | 95 (10.7) |  |