Table 1. Characteristics of Children With and Without Autism Spectrum Disorder.
| Characteristic | Children, No. (%) | |
|---|---|---|
| With ASD (n = 1307) | Without ASD (n = 130 949) | |
| Sex | ||
| Male | 1091 (83.5) | 66 960 (51.1) |
| Female | 216 (16.5) | 63 989 (48.9) |
| Gestational age at birth, median (IQR), wk | 39 (37-40) | 39 (38-40) |
| Maternal age at delivery, median (IQR), y | 32.2 (28.7-35.9) | 31.9 (28.2-35.4) |
| Multiple birth | ||
| Singleton | 1250 (95.6) | 126 942 (96.9) |
| Twins or triplets | 57 (4.4) | 4007 (3.1) |
| Parity | ||
| Nulliparous | 541 (41.4) | 67 834 (51.8) |
| Multiparous | 766 (58.6) | 63 114 (48.2) |
| Mother’s birthplace | ||
| Canada | 563 (43.1) | 66 284 (50.7) |
| India | 83 (6.4) | 12 275 (9.4) |
| China | 128 (9.8) | 11 004 (8.4) |
| Philippines | 127 (9.7) | 6606 (5.1) |
| United Kingdom | 24 (1.8) | 2512 (1.9) |
| United States | 21 (1.6) | 1986 (1.5) |
| Vietnam | 51 (3.9) | 2912 (2.2) |
| Hong Kong | 28 (2.1) | 2045 (1.6) |
| Other countries | 280 (21.5) | 25 102 (19.2) |
| Income band, median (IQR) | 390 (164-679) | 449 (189-738) |
| Urbanicity | ||
| Rural | 6 (0.5) | 456 (0.4) |
| Semiurban | 11 (0.9) | 729 (0.6) |
| Urban | 1277 (98.7) | 129 035 (99.1) |
| Month of birth | ||
| January | 119 (9.1) | 10 423 (8.0) |
| February | 88 (6.7) | 9717 (7.4) |
| March | 116 (8.9) | 10 762 (8.2) |
| April | 109 (8.3) | 10 679 (8.2) |
| May | 111 (8.5) | 11 258 (8.6) |
| June | 114 (8.7) | 11 096 (8.5) |
| July | 92 (7.0) | 11 379 (8.7) |
| August | 109 (8.3) | 11 556 (8.8) |
| September | 109 (8.3) | 11 591 (8.9) |
| October | 109 (8.3) | 11 267 (8.6) |
| November | 129 (9.9) | 10 719 (8.2) |
| December | 102 (7.8) | 10 502 (8.0) |
| Year of birth | ||
| 2004 | 235 (18.0) | 20 700 (15.8) |
| 2005 | 206 (15.8) | 20 759 (15.9) |
| 2006 | 200 (15.3) | 21 465 (16.4) |
| 2007 | 210 (16.1) | 22 302 (17.0) |
| 2008 | 232 (17.8) | 22 516 (17.2) |
| 2009 | 224 (17.1) | 23 207 (17.7) |
Abbreviations: ASD, autism spectrum disorder; IQR, interquartile range.