Table 1 Sociodemographic characteristics of the sample according to feeding status (1 month)

 Mother’s Age

4772

–

29.46^A (4.49)

1861

–

28.95^B (4.58)

4463

–

26.73^C (4.85)

420.75 (2)**

 Primipara (Y)

4617

42.7^A

–

1791

46.5^B

–

4183

39.7^C

–

18.55 (2)**

 Self-reported smoking in pregnancy (Y)

4686

15.8^A

–

1825

21.0^B

–

4268

31.1^C

–

109.92 (2)**

 Self-reported partner’s daily cigarette consumption

4242

–

3.06^A (7.09)

1617

–

4.02^B (8.08)

3476

–

5.25^C (8.47)

75.13 (2)**

Mother’s Education

4487^A

–

1721^B

–

3789^C

–

1203.61 (8)**

 CSE

7.9

9.5

22.6

 Vocational

6.9

8.5

14.6

 O-Level

32.6

37.7

42.5

 A-Level

29.9

28.8

16.3

 University Degree

22.7

15.6

3.9

 Partner’s Education

4256^A

–

1623^B

–

3398^C

–

830.94 (8)**

 CSE

10.9

14.7

25.6

 Vocational

7.2

8.6

12.2

 O-Level

21.1

23.8

26.4

 A-Level

29.4

32.5

28

 University Degree

31.4

20.3

7.9

 Crowding Index

4580^A

 –

1795^A

–

4163^B

–

345.88 (6)**

 ≤ 0,5 person per room

49

49.1

33.7

 > 0,5–0,75 person per room

30.9

32.2

32.8

 >  0,75–1 person per room

16

14

25

 > 1 person per room

4.1

4.7

8.6

 HOME Score

4363

–

10.41^A (1.55)

1643

–

10.37^A (1.59)

3661

–

10.13^B (1.64)

30.80 (2)**

 Maternal return to work (Y)

4432

34.3^A

–

1695

40^B

–

3789

28.8^C

–

70.71 (2)**

 Self-reported maternal smoking since birth (Y)

4594

14.3^A

–

1778

19.3^B

–

4057

31.3^C

–

370.46 (2)**

 Maternal depressive symptoms (32 gestational weeks)

4503

–

6.47^A (4.81)

1740

–

6.68^A (4.91)

4008

–

7.45^B (5.16)

42.80 (2)**

 Maternal depressive symptoms (8 weeks postpartum)

4590

–

5.61^A (4.40)

1776

–

6.08^B (4.80)

4054

–

6.30^C (4.98)

23.64 (2)**

 Baby’s sex (M)

4772

50.2^A

–

1861

53.1^B

–

4463

52.6^C

–

7.08 (2)*

 Baby’s Birthweight

4772

–

3498.61^A (445.40)

1861

–

3488.09^A (465.16)

4463

–

3461.16^B (469.63)

7.88 (2)**

 Gestational Age

4772

–

39.67^A (1.39)

1861

–

39.67^A (1.44)

4463

–

39.66^A (1.48)

0.89 (2)

 IQ (Total – 4y)

440

–

107.05^A (14.46)

181

–

106.73^A (12.68)

298

–

100.53^B (13.58)

21.70 (2) **

 IQ (Total – 8y)

3052

–

107.47^A (16.16)

1134

–

105.61^B (16.21)

1989

–

99.98^C (15.58)

134.25 (2) **

 Hyperactivity (SDQ – 4y)

3786

–

3.62^A (2.28)

1393

–

3.94^B (2.26)

3037

–

4.29^C (2.31)

72.07 (2)**

 Emotional Symptoms (SDQ – 4y)

3821

–

1.40^A (1.49)

1412

–

1.45^A (1.49)

3060

–

1.46^A (1.50)

0.24 (2)

 Conduct Problems (SDQ – 4y)

3816

–

1.84^A (1.36)

1408

–

1.98^B (1.48)

3064

–

2.02^C (1.41)

14.61 (2)**

 Total Behavior Score (SDQ – 4y)

3718

–

8.27^A (4.40)

1370

–

8.85^B (4.50)

2970

–

9.37^C (4.61)

48.95 (2)**

 Hyperactivity (SDQ – 9y)

3273

–

2.71^A (2.12)

1229

–

3.01^B (2.34)

2336

–

3.05^C (2.22)

20.96 (2)**

 Emotional Symptoms (SDQ – 9y)

3269

–

1.44^A (1.63)

1224

–

1.51^A (1.72)

2338

–

1.58^A (1.79)

1.75 (2)

 Conduct Problems (SDQ – 9y)

3279

–

1.21^A (1.34)

1224

–

1.26^A (1.31)

2339

–

1.33^B (1.41)

4.33 (2)**

 Total Behavior Score (SDQ – 9y)

3245

–

6.41^A (4.65)

1219

–

6.90^B (4.81)

2318

–

7.02^C (5.01)

12.99 (2)**