Table 1.
Comparisons of Child and Family Characteristics Between Preschoolers With Autism Spectrum Disorder and Controls in the Study to Explore Early Development
| Total sample (n = 1549) |
Among breastfed children (n = 1371) |
|||||
|---|---|---|---|---|---|---|
| Variable | ASDa n = 673 |
Controls n = 876 |
P-value | ASDa (n = 577) |
Controls (n = 794) |
P-value |
| Breastfeeding initiation (n, %) | ||||||
| Yes | 577 (85.7) | 794 (90.6) | 577 (100) | 794 (100) | n/a | |
| No (ref) | 96 (14.3) | 82 (9.4) | 0.003 | 0 | 0 | |
| Breastfeeding duration (months) | ||||||
| Mean (SDb) | n/a | n/a | 7.3 (7.2) | 9.3 (7.2) | <0.0001 | |
| Median | n/a | n/a | n/a | 6.0 | 8.5 | <0.0001 |
| Breastfeeding duration (tertiles) | ||||||
| High (≥12 months) | n/a | n/a | n/a | 141 (24.5) | 277 (34.9) | |
| Middle (6.0 months-<12.0 months) | n/a | n/a | n/a | 152 (26.3) | 255 (32.1) | |
| Low (<6.0 months) | n/a | n/a | n/a | 284 (49.2) | 262 (33.0) | <0.0001 |
| Child sex (n, %) | ||||||
| Female | 124 (18.4) | 412 (47.0) | 108 (18.7) | 379 (47.7) | ||
| Male | 549 (81.6) | 464 (53.0) | <0.0001 | 469 (81.3) | 415 (52.3) | <0.0001 |
| Gestational age (n, %) | ||||||
| Preterm (<37 weeks) | 109 (16.2) | 81 (9.3) | 91 (15.8) | 72 (9.1) | ||
| Term (≥37 weeks) | 560 (83.2) | 792 (90.4) | 482 (83.5) | 721 (90.8) | ||
| Missing | 4 (0.6) | 3 (0.3) | 0.0001 | 4 (0.7) | 1 (0.1) | 0.0002 |
| Child birthweight (n, %) | ||||||
| Low (<2500 g) | 89 (13.2) | 61 (7.0) | 75 (13.0) | 54 (6.8) | ||
| Normal (≥2500 g) | 568 (84.4) | 799 (91.2) | 487 (84.4) | 727 (91.6) | ||
| Missing | 16 (2.4) | 16 (1.8) | 0.0001 | 15 (2.6) | 13 (1.7) | 0.0002 |
| Child Apgar score at the 5th minutec | ||||||
| Mean (SDb) | 8.8 (0.6) | 8.9 (0.6) | 8.8 (0.6) | 8.9 (0.6) | ||
| Median | 9.0 | 9.0 | 0.08 | 9.0 | 9.0 | 0.18 |
| Maternal age at child’s birth (years) | ||||||
| Mean (SDb) | 31.7 (5.5) | 32.1 (5.3) | 31.9 (5.4) | 32.3 (5.1) | ||
| Median | 32.2 | 32.5 | 0.15 | 32.3 | 32.6 | 0.16 |
| Parity of the index child (n, %) | ||||||
| Second or later birth | 353 (52.4) | 470 (53.7) | 302 (52.3) | 419 (52.8) | ||
| First birth | 318 (47.3) | 404 (46.1) | 274 (47.5) | 373 (47.0) | ||
| Missing | 2 (0.3) | 2 (0.2) | 0.87 | 1 (0.2) | 2 (0.2) | 0.94 |
| Birth plurality (n, %) | ||||||
| Multiple | 54 (8.0) | 32 (3.7) | 48 (8.3) | 29 (3.6) | ||
| Singleton | 617 (91.7) | 842 (96.1) | 528 (91.5) | 763 (96.1) | ||
| Missing | 2 (0.3) | 2 (0.2) | 0.0009 | 1 (0.2) | 2 (0.3) | 0.001 |
| Maternal ethnicity (n, %) | ||||||
| Hispanic | 80 (11.9) | 77 (8.8) | 71 (12.3 | 71 (8.9) | ||
| Non-Hispanic | 592 (88.0) | 799 (91.2) | 505 (87.5) | 723 (91.1) | ||
| Missing | 1 (0.1) | 0 (0.1) | 0.07 | 1 (0.2) | 0 | 0.06 |
| Maternal race (n, %) | ||||||
| Non-Hispanic African American | 134 (19.9) | 106 (12.1) | 102 (17.7) | 78 (9.8) | ||
| Others | 113 (16.8) | 105 (12.0) | 104 (18.0) | 96 (12.1) | ||
| Non-Hispanic White | 423 (62.9) | 661 (75.5) | 369 (63.9) | 616 (77.6) | ||
| Missing | 3 (0.4) | 4 (0.4) | <0.0001 | 2 (0.4) | 4 (0.5) | <0.0001 |
| Maternal education at child’s birth (n, %) | ||||||
| No college degree | 317 (47.1) | 290 (33.1) | 248 (43.0) | 237 (29.9) | ||
| College degree or higher | 354 (52.6) | 585 (66.8) | 327 (56.7) | 556 (70.0) | ||
| Missing | 2 (0.3) | 1 (0.1) | <0.0001 | 2 (0.3) | 1 (0.1) | <0.0001 |
| Maternal place of birth (n, %) | ||||||
| Outside the United States | 143 (21.2) | 119 (13.6) | 136 (23.6) | 113 (14.2) | ||
| In the United States | 530 (78.8) | 757 (86.4) | <0.0001 | 441 (76.4) | 681 (85.8) | <0.0001 |
| Mother employment status (n, %) | ||||||
| Employed | 489 (72.7) | 696 (79.4) | 424 (73.5) | 629 (79.2) | ||
| Not employed | 183 (27.2) | 176 (20.1) | 153 (26.5) | 161 (20.3) | ||
| Missing | 1 (0.1) | 4 (0.5) | 0.003 | 0 | 4 (0.5) | 0.007 |
| Mother marital status (n, %)c | ||||||
| Not married | 173 (30.2) | 165 (22.4) | 126 (26.0) | 133 (20.0) | ||
| Married | 398 (69.6) | 573 (77.6) | 357 (73.8) | 531 (80.0) | ||
| Missing | 1 (0.2) | 0 | 0.003 | 1 (0.2) | 0 | 0.03 |
| Mother smoking status (n, %) | ||||||
| Smoker | 262 (38.9) | 301 (34.4) | 218 (37.8) | 272 (34.3) | ||
| Not smoker | 409 (60.8) | 571 (65.2) | 358 (62.0) | 518 (65.2) | ||
| Missing | 2 (0.3) | 4 (0.4) | 0.16 | 1 (0.2) | 4 (0.5) | 0.26 |
| Maternal neuropsychiatric diagnosesd (n, %) | ||||||
| Yes | 130 (19.3) | 89 (10.2) | 108 (18.7) | 78 (9.8) | ||
| No | 543 (80.7) | 786 (89.7) | 469 (81.3) | 715 (90.1) | ||
| Missing | 0 (0.0) | 1 (0.1) | <0.0001 | 0 | 1 (0.1) | <0.0001 |
| Mother broader autism phenotype | ||||||
| Yes | 43 (7.5) | 33 (4.3) | 0.01 | 34 (6.9) | 25 (3.6) | 0.009 |
| No | 530 (92.50) | 735 (95.7) | 460 (93.1) | 675 (96.4) | ||
| Mode of delivery of the child (n, %) | ||||||
| All others | 418 (62.1) | 606 (69.2) | 364 (63.1) | 555 (69.9) | ||
| Cesarean | 255 (37.9) | 270 (30.8) | 0.004 | 213 (36.9) | 239 (30.1) | 0.008 |
| Family income (n, %) | ||||||
| $10,000–<30,000 | 156 (23.2) | 114 (13.0) | 118 (20.4) | 86 (10.8) | ||
| $30,000–<70,000 | 175 (26.0) | 184 (21.0) | 146 (25.3) | 164 (20.7) | ||
| $70,000–<110,000 | 161 (23.9) | 245 (27.9) | 143 (24.8) | 232 (29.2) | ||
| $>110,000 | 161 (23.9) | 307 (35.1) | 155 (26.9) | 290 (36.5) | ||
| Missing | 20 (3.0) | 26 (3.0) | <0.0001 | 15 (2.6) | 22 (2.8) | <0.0001 |
| Study site | ||||||
| California | 101 (15.0) | 138 (15.8) | 93 (16.1) | 130 (16.4) | ||
| Colorado | 138 (20.5) | 188 (21.5) | 121 (20.9) | 176 (22.2) | ||
| Georgia | 132 (19.6) | 169 (19.3) | 0.67 | 112 (19.4) | 147 (18.5) | 0.92 |
| Maryland | 103 (15.3) | 123 (14.0) | 86 (14.9) | 110 (13.8) | ||
| North Carolina | 102 (15.2) | 151 (17.2) | 92 (15.9) | 139 (17.5) | ||
| Pennsylvania | 97 (14.41) | 107 (12.2) | 73 (12.6) | 92 (11.6) | ||
Note. Bolds values are assessed at a P-value of ≤0.20.
a
ASD: autism spectrum disorder.
b
SD: standard deviation.
c
Available only in five sites.
d
Neuropsychiatrie diagnoses include depression, anxiety, seizure disorder, and intellectual disability.