Table 1 Characteristics of the study sample according to ethnic group

Prenatal pre-pregnancy factors

Age (year)

32.4 (4.1)¹

29.0 (6.3)

26.5 (5.2)

27.6 (5.5)

31.3 (5.1)

Parity (%)

0

60.9

46.2

39.5

47.3

54.5

1

31.7

27.3

35.8

27.3

32.4

≥ 2

7.5

26.5

24.7

25.3

13.1

Maternal education (%)

0-5 years

7.0

42.6

56.5

54.2

22.4

6-10 years

34.3

47.8

38.5

40.8

40.0

> 10 years

58.7

9.6

5.0

5.0

37.6

Height (cm)

171 (6.2)

166 (6.2)

162 (5.1)

164 (6.7)

166 (7.2)

BMI mother (kg/m²)

22.6 (3.3)

24.4 (5.2)

24.6 (4.6)

25.1 (4.4)

22.7 (3.8)

Hypertension (%)

Pre-existent

3.2

3.8

3.1

4.7

3.6

Gestational

11.8

8.9

5.0

7.2

7.4

Diabetes (%)

Pre-existent

0.5

2.1

1.9

2.4

0.8

Gestational

0.1

0.8

0.6

0.0

0.4

Smoking (%)

None

90.4

89.5

80.2

97.6

90.0

1-5 cigarettes/day

6.2

7.6

13.0

1.2

6.2

≥ 6 cigarettes/day

3.4

3.0

6.8

1.2

3.8

Physical activity (%)

Not

6.6

34.5

32.7

34.7

20.1

Low

19.5

41.6

50.0

39.6

28.4

Moderate

32.0

16.4

11.7

20.8

23.8

High

41.9

7.6

5.6

4.9

27.7

Birth outcomes

Birth weight (kg)

3.51 (0.55)

3.26 (0.62)

3.39 (0.53)

3.46 (0.50)

3.39 (0.54)

Gestational age (wk)

39.9 (1.7)

39.3 (2.0)

39.5 (1.8)

40.0 (1.5)

39.8 (1.7)

Gender (%)

Boy

50.8

47.1

50.0

53.5

46.5

Girl

49.2

52.9

50.0

46.5

53.5

Postnatal factors

Exclusive breastfeeding (%)

None

18.5

18.9

5.6

12.2

18.3

< 1 month

7.1

12.6

17.3

13.1

8.6

1-3 months

30.7

40.3

31.5

42.0

30.9

> 3 months

43.7

28.2

45.7

32.7

42.2

Infant weight gain during the first 6 months (100 g/mo)

7.07 (1.34)

7.60 (1.56)

7.83 (1.50)

7.79 (1.47)

7.10 (1.35)

BMI 2 yr (kg/m²)

16.2 (1.3)

16.2 (1.4)

16.8 (1.7)

16.9 (1.7)

16.1 (1.4)

Overweight 2 yr (%)

7.1

9.2

19.8

16.7

8.8