Table 1. Characteristics of the Study Cohort.
| Characteristics and variables | Participants, No. (%) (N =1 047 649) | |
|---|---|---|
| Males (n = 538 283) | Females (n = 509 366) | |
| ASD diagnoses | 8128 (1.51) | 4098 (0.80) |
| ASD subcategories (% of ASD diagnoses) | ||
| Autistic disorder | 2338 (28.76) | 963 (23.50) |
| Asperger | 3743 (46.05) | 1943 (47.41) |
| Other | 2047 (25.18) | 1192 (29.09) |
| ASD with intellectual disabilities (% of ASD diagnoses) | 1664 (20.47) | 759 (18.52) |
| Follow-up, median (IQR), y | 19.0 (19.0-19.0) | 19.0 (19.0-19.0) |
| Birth year | ||
| 1985-1989 | 211 227 (39.24) | 199 032 (39.07) |
| 1990-1994 | 211 185 (39.23) | 200 401 (39.34) |
| 1995-1998 | 115 871 (21.53) | 109 933 (21.58) |
| Maternal age at delivery, y | ||
| <20 | 8418 (1.56) | 7851 (1.54) |
| 20-29 | 301 561 (56.02) | 284 987 (55.95) |
| 30-39 | 216 028 (40.13) | 205 165 (40.28) |
| 40-49 | 12 272 (2.28) | 11 357 (2.23) |
| ≥50 | 4 (<0.00) | 6 (<0.00) |
| Paternal age at delivery, y | ||
| <20 | 2129 (0.40) | 1989 (0.39) |
| 20-29 | 213 016 (39.57) | 201 420 (39.54) |
| 30-39 | 275 982 (51.27) | 261 764 (51.39) |
| 40-49 | 44 358 (8.24) | 41 589 (8.16) |
| ≥50 | 2798 (0.52) | 2604 (0.51) |
Abbreviations: ASD, autism spectrum disorder.