Table 1.
Characteristics of the ABCD Sample (n = 9,116†).
| Duration of breastfeeding | |||||
|---|---|---|---|---|---|
| 0 months (n = 1,875) | 1–6 months (n = 3,241) | 7–12 months (n = 2,198) | >12 months (n = 1,802) | p-Value‡ | |
| Age at baseline, months | 118.98 ± 7.28 | 119.39 ± 7.48 | 118.69 ± 7.56 | 118.47 ± 7.59 | <0.001 |
| Birth weight, oz | 106.82 ± 22.99 | 109.40 ± 24.19 | 115.19 ± 22.59 | 118.80 ± 20.89 | <0.001 |
| Maternal age at birth of child | 27.05 ± 6.42 | 29.02 ± 6.19 | 30.50 ± 5.54 | 31.10 ± 5.51 | <0.001 |
| Weeks born premature | 1.2 ± 2.47 | 1.2 ± 2.48 | 0.7 ± 1.87 | 0.5 ± 1.58 | <0.001 |
| Child's sex, n (%) | 0.723 | ||||
| Male | 947 (50.5) | 1,684 (52.0) | 1,145 (52.1) | 935 (51.9) | |
| Female | 928 (49.5) | 1,557 (48.0) | 1,053 (47.9) | 866 (48.1) | |
| Child's race/ethnicity, n (%) | <0.001 | ||||
| White | 692 (36.9) | 1,608 (49.6) | 1,387 (63.1) | 1,188 (65.9) | |
| Black | 617 (32.9) | 455 (14.0) | 158 (7.2) | 86 (4.8) | |
| Hispanic | 361 (19.3) | 772 (23.8) | 393 (17.9) | 319 (17.7) | |
| Asian | 13 (0.7) | 47 (1.5) | 46 (2.1) | 35 (1.9) | |
| Other | 192 (10.2) | 354 (10.9) | 210 (9.6) | 174 (9.7) | |
| Household income in dollars, n (%) | <0.001 | ||||
| <50,000 | 824 (43.9) | 914 (28.2) | 403 (18.3) | 324 (18.0) | |
| 50,000–99,999 | 431 (23.0) | 832 (25.7) | 579 (26.3) | 513 (28.5) | |
| 100,000–199,999 | 287 (15.3) | 886 (27.3) | 749 (34.1) | 641 (35.6) | |
| ≥200,000 | 88 (4.7) | 318 (9.8) | 326 (14.8) | 224 (12.4) | |
| Maternal educational level, n (%) | <0.001 | ||||
| < High school diploma | 221 (11.8) | 177 (5.5) | 91 (4.1) | 60 (3.3) | |
| HS Diploma/GED | 398 (21.2) | 320 (9.9) | 122 (5.6) | 89 (4.9) | |
| Some College | 743 (39.6) | 1,124 (34.7) | 517 (23.5) | 367 (20.4) | |
| Bachelor | 300 (16.0) | 897 (27.7) | 779 (35.4) | 627 (34.8) | |
| Post Graduate Degree | 211 (11.3) | 714 (22.0) | 688 (31.3) | 659 (36.6) | |
| Marital status, n (%) | <0.001 | ||||
| Married | 858 (45.8) | 2,114 (65.2) | 1,748 (79.5) | 1,411 (78.3) | |
| Not Married | 984 (52.5) | 1,095 (33.8) | 441 (20.1) | 386 (21.4) | |
| Tobacco use during pregnancy, n (%) | <0.001 | ||||
| No | 1,660 (88.5) | 3,078 (95.0) | 2,168 (98.6) | 1,774 (98.4) | |
| Yes | 213 (11.4) | 157 (4.8) | 30 (1.4) | 27 (1.5) | |
| Alcohol use during pregnancy, n (%) | <0.001 | ||||
| No | 1,858 (99.1) | 3,174 (97.9) | 2,134 (97.1) | 1,744 (96.8) | |
| Yes | 17 (0.9) | 59 (1.8) | 60 (2.7) | 54 (3.0) | |
| Planned pregnancy, n (%) | <0.001 | ||||
| No | 1,051 (56.1) | 1,346 (41.5) | 593 (27.0) | 485 (26.9) | |
| Yes | 810 (43.2) | 1,880 (58.0) | 1,592 (72.4) | 1,310 (72.7) | |
| Cesarean section, n (%) | <0.001 | ||||
| No | 1,061 (56.6) | 1,850 (57.1) | 1,475 (67.1) | 1,242 (68.9) | |
| Yes | 811 (43.3) | 1,391 (42.9) | 721 (32.8) | 560 (31.1) | |
| Prenatal vitamins, n (%) | <0.001 | ||||
| No | 135 (7.2) | 119 (3.7) | 58 (2.6) | 54 (3.0) | |
| Yes | 1,711 (91.3) | 3,089 (95.3) | 2,121 (96.5) | 1,728 (95.9) | |
| Gestational diabetes, n (%) | <0.001 | ||||
| No | 1,704 (90.9) | 2,982 (92.0) | 2,075 (94.4) | 1,689 (93.7) | |
| Yes | 160 (8.5) | 254 (7.8) | 121 (5.5) | 106 (5.9) | |
| Required oxygen at birth, n (%) | <0.001 | ||||
| No | 1,675 (89.3) | 2,808 (86.6) | 1,987 (90.4) | 1,642 (91.1) | |
| Yes | 180 (9.6) | 396 (12.2) | 193 (8.8) | 145 (8.0) | |
| Cyanosis, n (%) | 0.476 | ||||
| No | 1,796 (95.8) | 3,082 (95.1) | 2,108 (95.9) | 1,723 (95.6) | |
| Yes | 59 (3.1) | 116 (3.6) | 62 (2.8) | 59 (3.3) | |
| Slow heartbeat at birth, n (%) | 0.678 | ||||
| No | 1,790 (95.5) | 3,110 (96.0) | 2,113 (96.1) | 1,726 (95.8) | |
| Yes | 60 (3.2) | 94 (2.9) | 60 (2.8) | 46 (2.6) | |
| Relationship, n (%) | <0.001 | ||||
| Singleton | 1,174 (62.6) | 2,068 (63.8) | 1,564 (71.2) | 1,400 (77.7) | |
| Sibling | 227 (12.1) | 412 (12.7) | 333 (15.2) | 217 (12.0) | |
| Twin | 466 (24.9) | 748 (23.1) | 301 (13.7) | 185 (10.3) | |
| Triplet | 8 (0.4) | 13 (0.4) | 0 (0) | 0 (0) | |
| Days in Incubator | 1.5 ± 5.7 | 1.5 ± 5.1 | 1.0 ± 4.9 | 0.6 ± 3.0 | <0.001 |
| Family conflict (youth reported) | 2.4 ± 2.1 | 2.1 ± 1.9 | 1.9 ± 1.9 | 1.9 ± 1.9 | <0.001 |
| School risk (youth reported) | 20.0 ± 3.0 | 19.9 ± 2.8 | 19.9 ± 2.6 | 19.9 ± 2.8 | 0.940 |
Data are presented as mean (SD), except where noted.
†
Table includes only those who were not missing breastfeeding and neurocognitive data.
‡
t-test for continuous covariates and chi-square test for categorical covariates.