e-Table 1:
Characteristics of study population (n = 1,291,769) according to history of febrile seizures and epilepsy. Born in Denmark, 1978–2002 and alive and residing in Denmark on 10th birthday.
| No epilepsy or febrile seizure n =1,236,570 n (%) |
Febrile seizure n = 43,148 n (%) |
Epilepsy n = 10,355 n (%) |
Both epilepsy and febrile seizure n =1,696 n (%) |
|
|---|---|---|---|---|
| Female subjects | 604,514 (48.9) | 19,101 (44.3) | 4,736 (45.7) | 739 (43.6) |
| Gestational age, weeks | ||||
| ≤33 | 16,341 (1.3) | 840 (2.0) | 407 (3.9) | 60 (3.5) |
| 34–36 | 45,412 (3.7) | 2,060 (4.8) | 591 (5.7) | 102 (6.0) |
| 37–41 | 1,015,870 (82.2) | 35,331 (81.9) | 8,082 (78.1) | 1,345 (79.3) |
| ≥42 | 105,728 (8.6) | 3,476 (8.1) | 926 (8.9) | 132 (7.8) |
| Missing | 53,219 (4.3) | 1,441 (3.3) | 349 (3.4) | 57 (3.4) |
| Birth weight, g | ||||
| <1500 | 6,981 (0.6) | 365 (0.9) | 225 (2.2) | 34 (2.0) |
| 1500–2499 | 52,306 (4.2) | 2,404 (5.6) | 807 (7.8) | 112 (6.6) |
| 2500–2999 | 152,357 (12.3) | 5,959 (13.8) | 1,482 (14.3) | 282 (16.6) |
| 3000–3999 | 809,068 (65.4) | 27,585 (63.9) | 6,132 (59.2) | 1,024 (60.4) |
| ≥4000 | 209,716 (17.0) | 6,612 (15.3) | 1,629 (15.7) | 236 (13.9) |
| Missing | 6,142 (0.5) | 223 (0.5) | 80 (0.8) | 8 (0.5) |
| Apgar score (at 5 minutes) | ||||
| ≤7 | 16,640 (1.4) | 710 (1.7) | 457 (4.4) | 43 (2.5) |
| 8–9 | 65,800 (5.3) | 2,541 (5.9) | 812 (7.8) | 134 (7.9) |
| 10 | 1,141,048 (92.3) | 39,471 (91.5) | 8,921 (86.2) | 1,504 (88.7) |
| Missing | 13,082 (1.1) | 426 (1.0) | 165 (1.6) | 15 (0.9) |
| Maternal age at birth, years | ||||
| <20 | 31,758 (2.6) | 1,233 (2.9) | 373 (3.6) | 59 (3.5) |
| 20–24 | 260,543 (21.1) | 9,180 (21.3) | 2,430 (23.5) | 419 (24.7) |
| 25–29 | 492,120 (39.8) | 17,298 (40.1) | 3,929 (37.9) | 652 (38.4) |
| 30–34 | 331,203 (26.8) | 11,223 (26.0) | 2,670 (25.8) | 412 (24.3) |
| 35–39 | 106,333 (8.6) | 3,724 (8.6) | 830 (8.0) | 131 (7.7) |
| ≥40 | 14,613 (1.2) | 490 (1.1) | 123 (1.2) | 23 (1.4) |
| Paternal age at birth, years | ||||
| <20 | 8,668 (0.7) | 360 (0.8) | 89 (0.9) | 14 (0.8) |
| 20–24 | 134,968 (10.9) | 4,881 (11.3) | 1,333 (12.9) | 224 (13.2) |
| 25–29 | 410,920 (33.2) | 14,486 (33.6) | 3,386 (32.7) | 577 (34.0) |
| 30–34 | 408,627 (33.1) | 14,041 (32.5) | 3,249 (31.4) | 529 (31.2) |
| 35–39 | 191,797 (15.5) | 6,559 (15.2) | 1,535 (14.8) | 242 (14.3) |
| ≥40 | 81,590 (6.6) | 2,821 (6.5) | 763 (7.4) | 110 (6.5) |
| Maternal education, start of follow-up | ||||
| Primary education | 331,420 (26.8) | 11,420 (26.5) | 3,375 (32.6) | 590 (34.8) |
| Secondary education | 512,570 (41.5) | 18,155 (42.1) | 4,162 (40.2) | 661 (39.0) |
| Undergraduate education | 303,863 (24.6) | 10,395 (24.1) | 2,190 (21.2) | 348 (20.5) |
| Graduate education | 75,565 (6.1) | 2,711 (6.3) | 504 (4.9) | 82 (4.8) |
| Missing | 13,152 (1.1) | 467 (1.1) | 124 (1.2) | 15 (0.9) |
| Paternal income, start of follow-up | ||||
| 1st quintile | 243,647 (19.7) | 8,800 (20.4) | 2,597 (25.1) | 444 (26.2) |
| 2nd quintile | 244,352 (19.8) | 8,560 (19.8) | 2,184 (21.1) | 380 (22.4) |
| 3rd quintile | 244,601 (19.8) | 8,544 (19.8) | 2,011 (19.4) | 321 (18.9) |
| 4th quintile | 244,870 (19.8) | 8,537 (19.8) | 1,780 (17.2) | 289 (17.0) |
| 5th quintile | 245,327 (19.8) | 8,251 (19.1) | 1,644 (15.9) | 239 (14.1) |
| Missing | 13,773 (1.1) | 456 (1.1) | 139 (1.3) | 23 (1.4) |
| Maternal psychiatric diagnosis | ||||
| Yes | 128,422 (10.4) | 5,183 (12.0) | 1,657 (16.0) | 275 (16.2) |
| No | 1,108.148 (89.6) | 37,965 (88.0) | 8,698 (84.0) | 1,421 (83.8) |
| Paternal psychiatric diagnosis | ||||
| Yes | 105,076 (8.5) | 4,155 (9.6) | 1,227 (11.9) | 208 (12.3) |
| No | 1,131,494 (91.5) | 38,993 (90.4) | 9,128 (88.2) | 1,488 (87.7) |
| Diagnosis of ADHD, start of follow-up | ||||
| Yes | 5,990 (0.5) | 343 (0.8) | 215 (2.1) | 57 (3.4) |
| No | 1,230,580 (99.5) | 42,805 (99.2) | 10,140 (97.9) | 1,639 (96.6) |
| Diagnosis of ASD, start of follow-up | ||||
| Yes | 4,814 (0.4) | 251 (0.6) | 309 (3.0) | 58 (3.4) |
| No | 1,231,756 (99.6) | 42,897 (99.4) | 10,046 (97.0) | 1,638 (96.6) |