Table 1 Demographics and baseline characteristics by feeding groups in the analysis set (N = 106)Subject characteristics

Age at enrollment, days (median [IQR])

43 (30 − 49)

33 (29 − 39)

39 (32 − 49)

0.097

0.706

0.067

Gender

1.000

1.000

1.000

 Male

19 (50.0%)

11 (50.0%)

22 (47.8%)

-

-

-

 Female

19 (50.0%)

11 (50.0%)

24 (52.2%)

-

-

-

Ethnicity

1.000

0.202

0.324

 Caucasian

36 (94.7%)

21 (95.5%)

46 (100.0%)

-

-

-

 Other

2 (5.3%)

1 (4.6%)

0 (0.0%)

-

-

-

Days breastfed since birth (median [IQR])

43 (30 − 49)

33 (29 − 39)

0 (0 − 5)

0.100

< 0.001

< 0.001

Days formula-fed since birth (median [IQR])

0 (0 − 0)

30 (16 − 32)

38 (30 − 49)

< 0.001

< 0.001

0.007

Mother’s age, days (median [IQR])

33 (30 − 36)

32 (29 − 35)

29 (26 − 34)

0.299

0.004

0.150

Mother’s highest level of education

0.600

0.202

0.194

 Primary school

0 (0.0%)

0 (0.0%)

5 (10.9%)

-

-

-

 High school

9 (23.7%)

5 (22.8%)

10 (21.7%)

-

-

-

 College or above

18 (47.4%)

13 (59.1%)

17 (37.0%)

-

-

-

 Professional school

11 (29.0%)

4 (18.2%)

14 (30.4%)

-

-

-

Mother smoked during pregnancy

1 (2.6%)

2 (9.1%)

10 (21.7%)

0.548

0.010

0.311

Father’s age, days (median [IQR])

34 (31 − 37)

36 (33 − 39)

31 (29–36)

0.160

0.040

0.006

Father’s highest level of education

0.664

0.012

0.043

 Primary school

0 (0.0%)

0 (0.0%)

5 (10.9%)

-

-

-

 High school

6 (15.8%)

4 (18.2%)

7 (15.2%)

-

-

-

 College or above

18 (47.4%)

12 (54.6%)

10 (21.7%)

-

-

-

 Professional school

14 (36.8%)

5 (22.8%)

17 (37.0%)

-

-

-

 Missing, unknown, or less than primary school

0 (0.0%)

1 (4.6%)

7 (15.2%)

-

-

-

Father is a smoker

8 (21.1%)

9 (40.9%)

25 (54.4%)

0.132

0.002

0.430