Table 2.
Characteristics of the Early Markers for Autism study population
| Characteristics | ASD | DD1 | GP | ASD vs. GP | ASD vs. DD | DD vs. GP | |||
|---|---|---|---|---|---|---|---|---|---|
| (N = 415) | (N = 188) | (N = 428) | |||||||
|
|
|||||||||
| n | % | n | % | n | % | p value | p value | p value | |
| Child’s sex2 | 0.9102 | < 0.0001 | < 0.0001 | ||||||
| Male | 343 | 82.7% | 106 | 56.4% | 355 | 82.9% | |||
| Female | 72 | 17.3% | 82 | 43.6% | 73 | 17.1% | |||
| Plurality | 0.5873 | 0.5800 | 0.3105 | ||||||
| Singleton | 405 | 97.6% | 182 | 96.8% | 420 | 98.1% | |||
| Multiple | 10 | 2.4% | 6 | 3.2% | 8 | 1.9% | |||
| Parity | 0.0109 | 0.0025 | 0.2863 | ||||||
| Primiparous | 196 | 47.2% | 64 | 34.0% | 165 | 38.6% | |||
| Multiparous | 219 | 52.8% | 124 | 66.0% | 263 | 61.4% | |||
| Mother’s race | 0.1134 | < 0.0001 | 0.0059 | ||||||
| Caucasian | 307 | 74.0% | 164 | 87.2% | 340 | 79.4% | |||
| Asian | 88 | 21.2% | 12 | 6.4% | 67 | 15.7% | |||
| Other | 20 | 4.8% | 12 | 6.4% | 21 | 4.9% | |||
| Mother’s ethnicity | 0.0060 | < 0.0001 | < 0.0001 | ||||||
| Hispanic | 157 | 37.8% | 131 | 69.7% | 202 | 47.2% | |||
| Non-hispanic | 258 | 62.2% | 57 | 30.3% | 226 | 52.8% | |||
| Mother’s birth country | 0.0288 | < 0.0001 | < 0.0001 | ||||||
| United States | 210 | 50.6% | 83 | 44.1% | 207 | 48.4% | |||
| Mexico | 94 | 22.7% | 87 | 46.3% | 129 | 30.1% | |||
| Other | 111 | 26.7% | 18 | 9.6% | 92 | 21.5% | |||
| Mean maternal age, years (+/− SD) | 30.01 (5.67) | 27.18 (6.25) | 28.70 (5.40) | 0.0006 | < 0.0001 | 0.0022 | |||
| Maternal Age (Years) | 0.0432 | < 0.0001 | 0.0003 | ||||||
| <20 | 14 | 3.4% | 26 | 13.8% | 22 | 5.1% | |||
| 20–24 | 58 | 14.0% | 43 | 22.9% | 72 | 16.8% | |||
| 25–29 | 109 | 26.3% | 52 | 27.7% | 129 | 30.1% | |||
| 30–34 | 154 | 37.1% | 44 | 23.4% | 151 | 35.3% | |||
| ≥35 | 80 | 19.3% | 23 | 12.2% | 54 | 12.6% | |||
| Mean paternal age, years (+/− SD) | 32.76 (6.11) [N = 398] | 30.43 (7.55) [N = 171] | 31.47 (6.12) [N = 412] | 0.0026 | 0.0001 | 0.0843 | |||
| Paternal Age (Years) | 0.0892 | < 0.0001 | 0.0316 | ||||||
| <20 | 7 | 1.8% | 8 | 4.7% | 8 | 1.9% | |||
| 20–24 | 29 | 7.3% | 32 | 18.7% | 50 | 12.1% | |||
| 25–29 | 87 | 21.9% | 44 | 25.7% | 96 | 23.3% | |||
| 30–34 | 120 | 30.2% | 39 | 22.8% | 127 | 30.8% | |||
| ≥35 | 155 | 38.9% | 48 | 28.1% | 131 | 31.8% | |||
| Maternal Weight at XAFP Blood draw (lbs) | 151.91 (36.04) | 158.98 (37.12) | 150.70 (34.02) | 0.6149 | 0.0275 | 0.0070 | |||
| Gestational Age at XAFP Blood draw (days) | 119.20 (8.84) | 119.99 (9.23) | 118.68 (8.40) | 0.3811 | 0.3182 | 0.0849 | |||
| Gestational Age at Birth (weeks) | 39.29 (0.21) [N = 402] | 38.36 (0.32) [N = 179] | 39.85 (0.25) [N = 416] | 0.0869 | 0.0128 | 0.0007 | |||
| <33 (weeks) | 9 | 2.2% | 15 | 8.4% | 7 | 1.7% | 0.8336 | 0.0011 | 0.0001 |
| 33–<37 | 39 | 9.7% | 23 | 12.8% | 39 | 9.4% | |||
| ≥37 | 354 | 88.1% | 141 | 78.8% | 370 | 88.9% | |||
| Birth Season2 | 0.9688 | 0.0479 | 0.0482 | ||||||
| Spring (March – May) | 129 | 31.08% | 51 | 27.13% | 132 | 30.84% | |||
| Summer (June – August) | 116 | 27.95% | 41 | 21.81% | 116 | 27.10% | |||
| Autumn (September – November) | 94 | 22.65% | 44 | 23.40% | 103 | 24.07% | |||
| Winter (December – February) | 76 | 18.31% | 52 | 27.66% | 77 | 17.99% | |||
1
Trisomy 21 cases were excluded from the DD group
2
GP controls were frequency matched to ASD cases on child’s sex, birth month and birth year.
Bolding indicates p-values <0.05.
Abbreviations: ASD: autism spectrum disorder; DD: developmental delay; GP: general population.