Table 1 Demographic information for the full sample of infants with data at either 6 or 12 months (N’s provided separately at the bottom of the table)

Sex

Female

6 (13.6%)

67 (47.5%)

28 (34.1%)

 < 0.001

Male

38 (86.4%)

74 (52.5%)

54 (65.9%)

Maternal education

High School

2 (4.5%)

7 (5.0%)

3 (3.7%)

0.102

College

30 (68.2%)

90 (63.8%)

44 (53.7%)

Graduate

12 (27.3%)

44 (31.2%)

35 (42.7%)

Race

Black/African-American

1 (2.3%)

5 (3.5%)

4 (4.9%)

0.46

More Than One Race

6 (13.6%)

16 (11.3%)

9 (11.0%)

White

37 (84.1%)

117 (83.0%)

69 (84.1%)

Asian

0 (0%)

3 (2.1%)

0 (0%)

Ethnicity

Hispanic

2 (4.5%)

9 (6.4%)

5 (6.1%)

0.416

Not Hispanic

42 (95.5%)

130 (92.2%)

77 (93.9%)

Unknown/Not Reported

0 (0%)

2 (1.4%)

0 (0%)

24-Month MSEL expressive language T-score

Mean (SD)

36.4 (11.3)

49.1 (11.2)

52.9 (9.34)

 < 0.001

Median [Min, Max]

36.0 [20.0, 58.0]

48.0 [25.0, 76.0]

54.0 [28.0, 73.0]

Missing

1 (2.3%)

3 (2.1%)

0 (0%)

24-Month MSEL receptive language T-score

Mean (SD)

33.3 (16.2)

52.1 (10.2)

57.2 (8.11)

 < 0.001

Median [Min, Max]

23.0 [20.0, 68.0]

52.0 [20.0, 74.0]

58.0 [30.0, 77.0]

Missing

1 (2.3%)

3 (2.1%)

0 (0%)

24-Month language delay

No language delay

16 (36.4%)

121 (85.8%)

80 (97.6%)

 < 0.001

Language delay

27 (61.4%)

17 (12.1%)

2 (2.4%)

Unknown

1 (2.3%)

3 (2.1%)

0 (0%)

6-Month sample Ns

N = 33

N = 105

N = 73

12-Month sample Ns

N = 39

N = 129

N = 71