Table 1.
Baseline characteristics of the cohorts
| 1980–2002 |
1973–2002 |
|||
|---|---|---|---|---|
| Variables | Non-bereaved N=1 414 287 (97.30%) | Bereaved N=38 215 (2.70%) | Non-bereaved N=1 826 806 (97.826%) | Bereaved N=40 698 (2.18%) |
| Gender | ||||
| Male | 726 671 (51) | 19 439 (51) | 942 715 (52) | 20 763 (51) |
| Female | 687 614 (49) | 18 776 (49) | 884 089 (48) | 19 935 (49) |
| Missing | 2 (0) | 2 (0) | ||
| Apgar score at 5 min | ||||
| 10 | 1 264 861 (89) | 36 222 (95) | 1 366 773 (75) | 37 201 (91) |
| 8–9 | 32 734 (2) | 950 (2) | 34 774 (2) | 985 (2) |
| 0–7 | 7073 (1) | 234 (1) | 7371 (0) | 238 (1) |
| Missing | 109 619 (8) | 809 (2) | 417 888 (23) | 2274 (6) |
| Birth Weight* | ||||
| ≥2500 g | 1 245 876 (88) | 35 432 (93) | 1 295 492 (71) | 36 006 (88) |
| <2500 g | 64 623 (5) | 2133 (6) | 67 151 (4) | 2180 (5) |
| Missing | 103 788 (7) | 650 (2) | 464 163 (25) | 2512 (6) |
| Gestational age* | ||||
| 0=37+ weeks | 1 222 362 (86) | 34 990 (92) | 1 294 836 (71) | 35 681 (88) |
| 1=less than 37 weeks | 70 316 (5) | 2303 (6) | 73 720 (4) | 2359 (6) |
| Missing | 121 609 (9) | 922 (2) | 458 250 (25) | 2658 (7) |
| Parity | ||||
| 1 | 645 886 (46) | 14 321 (37) | 956 594 (52) | 15 024 (37) |
| 2 | 525 185 (37) | 15 270 (40) | 616 084 (34) | 16 734 (41) |
| 3 | 234 560 (17) | 8621 (23) | 242 170 (13) | 8932 (22) |
| Missing | 8656 (1) | 3 (0) | 11 958 (1) | 8 (0) |
| Maternal age, years | ||||
| <27 | 495 432 (35) | 11 267 (29) | 714 820 (39) | 12 682 (31) |
| 27–30 | 439 574 (31) | 11 618 (30) | 551 663 (30) | 12 270 (30) |
| 31 and over | 473 560 (33) | 15 330 (40) | 553 484 (30) | 15 746 (39) |
| Missing | 5721 (0) | 6839 (0) | ||
| Maternal education, years* | ||||
| 0–9 | 428 202 (30) | 12 658 (33) | 428 202 (23) | 12 658 (31) |
| 10–11 | 416 669 (29) | 12 351 (32) | 416 669 (23) | 12 351 (30) |
| 12+ | 394 823 (28) | 11 748 (31) | 394 823 (22) | 11 748 (29) |
| Missing | 174 593 (12) | 1458 (4) | 587 112 (32) | 3941 (10) |
*Data available from 1980.