Table 1.
Demographic and medical characteristics of the sample
| Sample characteristics | Full sample (N = 601) |
Included (N = 470) |
Excluded (N = 131) |
p-value |
|---|---|---|---|---|
| Maternal characteristics* | ||||
| Maternal education: < HS/GED | 13% (79/598) | 15% (68/468) | 8.5% (11/130) | 0.07 |
| Low SES: Hollingshead = 5 | 9.9% (59/599) | 8.5% (40/469) | 15% (19/130) | 0.04 |
| Minority race or ethnicity± | 58% (347/601) | 55% (257/470) | 69% (90/131) | 0.004 |
| No partner | 25% (152/600) | 26% (124/470) | 22% (28/130) | 0.26 |
| Neonatal characteristics | Full sample (N = 704) |
Included (N = 542) |
Excluded (N = 162) |
p-value |
|---|---|---|---|---|
| Infant gender = Male | 56% (388/697) | 55% (299/539) | 56% (89/158) | 0.85 |
| Multiple gestation | 26% (184/697) | 27% (145/539) | 25% (39/158) | 0.58 |
| Cesarean delivery | 71% (495/696) | 71% (382/539) | 72% (113/157) | 0.79 |
| PMA at Birth (weeks) | 27.0 ± 1.92 | 27.0 ± 1.92 | 27.0 ± 1.92 | 0.86 |
| Birth weight (grams) | 948.3 ± 280.6 | 951.1 ± 281.8 | 938.5 ± 277.0 | 0.62 |
| Head circumference (cm) | 24.5 ± 2.43 | 24.5 ± 2.48 | 24.4 ± 2.24 | 0.70 |
| PMA at Discharge (weeks) | 40.5 ± 5.43 | 40.3 ± 5.20 | 41.29 ± 6.12 | 0.05 |
| Length of NICU stay (LOS days) | 93.5 ± 41.9 | 91.7 ± 40.1 | 99.7 ± 47.4 | 0.05 |
| Weight at discharge (grams) | 3013 ± 905 | 3001 ± 861 | 3057 ± 1042 | 0.50 |
| Severe retinopathy of prematurity | 5.9% (41/697) | 6.3% (34/539) | 4.4% (7/158) | 0.38 |
| Necrotizing enterocolitis/sepsis | 18% (128/697) | 19% (103/539) | 16% (25/158) | 0.35 |
| Chronic lung disease | 51% (357/697) | 51% (277/539) | 51% (80/158) | 0.87 |
| Serious brain injury+ | 13% (92/694) | 13% (69/539) | 15% (23/155) | 0.51 |
Means ± standard deviations (continuous) or percentage and frequencies (categorical) of demographic and medical characteristics. p-values refer to the comparison of included versus excluded individuals and were obtained from t-tests (continuous variables) and chi-squared tests (categorical variables)
PMA, postmenstrual age; HS, high school; GED, General Equivalency Diploma; SES, socioeconomic status
*All mothers with prenatal data were included in the latent class analysis. Included versus excluded in this Table refers to individuals with data for the epigenome-wide analysis
±Minority race or ethnicity was defined as any non-White race (e.g., Black, Asian) or ethnicity (e.g., Hispanic and/or Latino/a)
+Serious brain injury included parenchymal echodensity, periventricular leukomalacia, or ventricular dilation diagnosed via cranial ultrasound