Table 1 Demographic characteristics of the ABCD participants enrolled for neuroimaging analysis
| Â | Baseline analysis (9-10 years) | Â | Follow-up analysis (11-12 years) | Â | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|  |  ≤ 33 weeks (N = 432) | 34 ~ 35 weeks (N = 528) | 36 weeks (N = 563) | 37 ~ 39 weeks (N = 542) |  ≥ 40 weeks (N = 9138) | F/χ2 (P value) |  ≤ 33 weeks (N = 266) | 34 ~ 35 weeks (N = 205) | 36 weeks (N = 267) | 37 ~ 39 weeks (N = 261) |  ≥ 40 weeks (N = 4297) | F/χ2 (P value) |
Age (years) a | 10.0 (0.62) | 10.0 (0.59) | 10.0 (0.61) | 10.0 (0.61) | 9.9 (0.63) | 13.1 (1.1 × 10−10) | 12.0 (0.63) | 12.0 (0.64) | 12.1 (0.64) | 12.0 (0.63) | 11.9 (0.64) | 8.5 (7.6 × 10−7) |
Gender b | Â | Â | Â | Â | Â | 5.5 (0.24) | Â | Â | Â | Â | Â | 3.16 (0.53) |
 Female | 201 | 237 | 284 | 245 | 4399 |  | 111 | 93 | 116 | 121 | 1999 |  |
 Male | 231 | 291 | 279 | 297 | 4739 |  | 155 | 112 | 151 | 140 | 2298 |  |
BMI a | 18.7 (4.32) | 17.9 (3.83) | 18.8 (4.07) | 18.9 (3.99) | 18.8 (4.18) | 5.7 (0.001) | 18.6 (3.71) | 18.1 (3.87) | 18.0 (4.0) | 19.1 (4.27) | 18.7 (4.00) | 3.48 (0.008) |
Total parent income b |  |  |  |  |  | 48.8 (6.8 × 10−8) |  |  |  |  |  | 33.4 (5.3 × 10−5) |
 < $50,000 (low) | 127 | 85 | 135 | 119 | 2530 |  | 53 | 53 | 36 | 58 | 1153 |  |
 $50,000–100,000 (middle) | 108 | 148 | 162 | 137 | 2359 |  | 72 | 59 | 87 | 85 | 1171 |  |
 > $100,000 (high) | 197 | 295 | 266 | 286 | 4249 |  | 141 | 93 | 144 | 118 | 1973 |  |
Parents Education a | 16.2 (2.66) | 17.2 (2.17) | 16.8 (2.46) | 16.7 (2.66) | 16.6 (2.81) | 9.52 (1.2 × 10−7) | 16.6 (2.74) | 16.4 (2.40) | 17.3 (2.00) | 16.7 (2.45) | 16.7 (2.70) | 3.73 (0.005) |
Race b |  |  |  |  |  | 42.2 (3.1 × 10−5) |  |  |  |  |  | 21.3 (0.05) |
 White | 302 | 406 | 389 | 409 | 6183 |  | 32 | 26 | 30 | 31 | 609 |  |
 Black | 68 | 63 | 99 | 51 | 1503 |  | 213 | 154 | 212 | 197 | 3077 |  |
 Indian | 2 | 2 | 2 | 3 | 52 |  | 20 | 25 | 23 | 31 | 584 |  |
 Others | 60 | 57 | 73 | 79 | 1400 |  | 1 | 0 | 2 | 2 | 27 |  |
Puberty a | 1.89 (0.68) | 1.80 (0.57) | 1.90 (0.59) | 1.83 (0.56) | 1.82 (0.62) | 3.31 (0.01) | 1.75 (0.53) | 1.88 (0.63) | 1.73 (0.54) | 1.87 (0.56) | 1.79 (0.61) | 3.30 (0.01) |
Maternal age at birth a | 32.2 (7.22) | 32.7 (6.58) | 32.5 (7.53) | 33.2 (8.17) | 31.7 (8.39) | 6.66 (2.4 × 10−5) | 33.2 (7.05) | 33.0 (6.84) | 32.4 (6.29) | 32.2 (7.06) | 31.8 (8.08) | 3.24 (0.01) |
Prenatal substance exposure before knowing of pregnancy b | Â | Â | Â | Â | Â | 15.2 (0.51) | Â | Â | Â | Â | Â | 5.29 (0.99) |
 Tobacco | 54 | 71 | 106 | 85 | 1179 |  | 46 | 18 | 30 | 50 | 536 |  |
 Marijuana | 19 | 17 | 36 | 27 | 530 |  | 11 | 5 | 6 | 14 | 235 |  |
 Cocaine/crack | 3 | 3 | 4 | 2 | 73 |  | 1 | 0 | 2 | 1 | 33 |  |
 Heroin/morphine | 0 | 1 | 0 | 0 | 21 |  | 0 | 0 | 1 | 0 | 11 |  |
 Oxytocin | 2 | 1 | 0 | 1 | 35 |  | 0 | 1 | 0 | 0 | 16 |  |
Prenatal substance exposure after knowing of pregnancy b |  |  |  |  |  | 13.7 (0.62) |  |  |  |  |  | 14.5 (0.27) |
 Tobacco | 21 | 28 | 40 | 32 | 445 |  | 17 | 9 | 13 | 14 | 184 |  |
 Marijuana | 7 | 4 | 13 | 9 | 189 |  | 7 | 2 | 1 | 4 | 83 |  |
 Cocaine/crack | 2 | 2 | 2 | 2 | 35 |  | 1 | 0 | 1 | 0 | 16 |  |
 Heroin/morphine | 0 | 1 | 0 | 0 | 17 |  | 0 | 0 | 1 | 0 | 8 |  |
 Oxytocin | 2 | 1 | 0 | 1 | 19 |  | 0 | 1 | 0 | 0 | 6 |  |