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Table 1 Demographic and medical characteristics of the sample

From: Prenatal risk factors and neonatal DNA methylation in very preterm infants

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

  1. 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)
  2. PMA, postmenstrual age; HS, high school; GED, General Equivalency Diploma; SES, socioeconomic status
  3. *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
  4. ±Minority race or ethnicity was defined as any non-White race (e.g., Black, Asian) or ethnicity (e.g., Hispanic and/or Latino/a)
  5. +Serious brain injury included parenchymal echodensity, periventricular leukomalacia, or ventricular dilation diagnosed via cranial ultrasound