Table 1 Mean and standard deviation of neurodevelopment indices by infant age and participants’ characteristics (n = 343) a
Characteristic | n (%) or mean ± SD b | 6 months (n = 306) | 12 months (n = 252) | ||||||
|---|---|---|---|---|---|---|---|---|---|
MDI | P-value | PDI | P-value | MDI | P-value | PDI | P-value | ||
Total | 98.0 ± 10.9 | 97.0 ± 13.9 | 101.3 ± 15.9 | 94.6 ± 16.2 | |||||
Maternal age | 30.1 ± 3.3 | ||||||||
≤30 years | 208 (60.6) | 98.9 ± 11.7 | 0.10 | 98.1 ± 14.1 | 0.08 | 100.5 ± 15.8 | 0.34 | 94.5 ± 15.5 | 0.89 |
>30 years | 135 (39.4) | 96.7 ± 9.3 | 95.2 ± 13.4 | 102.5 ± 16.1 | 94.8 ± 17.2 | ||||
Maternal education | |||||||||
≤ High school | 58 (16.9) | 98.0 ± 11.0 | 1.00 | 98.5 ± 13.4 | 0.39 | 100.5 ± 14.0 | 0.75 | 95.0 ± 18.5 | 0.88 |
≥ University | 285 (83.1) | 98.0 ± 11.0 | 96.7 ± 13.9 | 101.4 ± 16.3 | 94.6 ± 15.7 | ||||
Monthly family income | |||||||||
< $2,000 | 41 (12.0) | 98.7 ± 9.2 | 0.78 | 98.7 ± 14.7 | 0.45 | 97.2 ± 17.4 | 0.10 | 96.0 ± 18.8 | 0.61 |
$2,000-$4,000 | 165 (48.1) | 98.3 ± 11.9 | 97.5 ± 14.1 | 100.5 ± 15.2 | 93.7 ± 16.3 | ||||
> $4,000 | 137 (39.9) | 97.5 ± 10.0 | 95.8 ± 13.2 | 103.7 ± 16.2 | 95.4 ± 15.1 | ||||
Sex | |||||||||
Male | 175 (51.0) | 97.0 ± 10.9 | 0.09 | 94.6 ± 14.4 | 0.002 | 99.7 ± 16.5 | 0.11 | 93.4 ± 16.6 | 0.22 |
Female | 168 (49.0) | 99.1 ± 10.9 | 99.5 ± 12.9 | 102.9 ± 15.1 | 95.9 ± 15.6 | ||||
Birth Weight (kg) | 3.33 ± 0.35 | ||||||||
Gestational age (weeks) | 39.2 ± 1.0 | ||||||||