Table 1 Characteristics of mother–child pairs included in analyses of cord blood, early-childhood, and mid-childhood samples

Maternal characteristics

  Age at enrollment, years, mean (SD)

32.1 (5.3)

0

32.3 (5.0)

0

0

  Pre-pregnancy BMI, kg/m², mean (SD)

24.8 (5.3)

1

25.9 (6.3)

1

4

  Pre-pregnancy obesity^a

71 (14.6%)

1

22 (18.3%)

1

4

  College graduate

322 (66.4)

0

86 (71.7%)

2

  Annual household income > $70,000

269 (59.9%)

36

71 (64.6%)

20

42

  Smoking status

0

0

0

    Former smoker

102 (21.0%)

–

28 (23.3%)

–

–

    Smoking during pregnancy

54 (11.1%)

–

18 (15.0%)

–

–

    Never smoker

329 (67.8%)

–

74 (61.7%)

–

–

Child characteristics

  Female

231 (47.6%)

0

58 (48.3%)

0

0

  Gestational age, weeks, mean (SD)

39.7 (1.6)

0

39.6 (1.6)

0

0

  Preterm^b

23 (4.7%)

0

7 (5.8%)

0

0

  Birth weight for GA z-score, mean (SD)

0.3 (1.0)

0

0.2 (0.9)

0

1

  Race/ethnicity

0

0

1

    Asian

16 (3.3%)

–

6 (5.0%)

–

–

    Black

62 (12.8%)

–

10 (8.3%)

–

–

    Hispanic

26 (5.4%)

–

4 (3.3%)

–

–

    More than one race or other

56 (11.6%)

–

16 (13.3%)

–

–

    White

325 (67.0%)

–

84 (70.0%)

–

–

  Age at sample collection, years, mean (SD)

–

–

3.4 (0.5)

0

0

  Epigenetic age measures

    Bohlin EGA, weeks, mean (SD)

40.3 (1.2)

0

–

–

0

    Bohlin EGAA, weeks, mean (SD)

0.0 (0.7)

0

–

–

0

    Knight EGA, weeks, mean (SD)

38.8 (1.7)

0

–

–

0

    Knight EGAA, weeks, mean (SD)

0.0 (1.4)

0

–

–

0

    Horvath EA, years, mean (SD)

0.1 (0.2)

0

4.2 (1.0)

0

0

    Horvath EAA, years, mean (SD)

0.0 (0.2)

0

0.0 (0.8)

0

0

    Skin & blood EA, years, mean (SD)

− 0.3 (0.1)

0

2.6 (0.7)

0

0

    Skin & blood EAA, years, mean (SD)

0.0 (0.1)

0

0.0 (0.5)

0

0