Table 1 Basic characteristics of the two groups of cohorts

Mother’s age (years)

27.3 ± 3.9

27.5 ± 4.1

-0.379

0.414

29.0 ± 4.4

29.2 ± 4.5

-0.382

0.702

Mother’s BMI (x ± s)

20.8 ± 1.6

21.0 ± 1.5

-1.094

0.274

21.0 ± 1.8

21.0 ± 1.9

-0.272

0.786

Parity (n, %)

5.733

0.017

2.521

0.112

 One child

724 (53.8)

72 (43.9)

596 (46.5)

65 (54.1)

 Second child or more

622 (46.2)

92 (56.0)

683 (53.4)

55 (45.8)

GBS Screening (n, %)

1206.195

 < 0.001

730.014

 < 0.001

 Positive

33 (2.5)

162 (98.7)

65 (5.1)

108 (90.0)

 Negative

1313 (97.5)

2 (1.3)

1214 (94.9)

12 (10.0)

Mother’s allergy history (n, %)

128 (9.5)

12 (7.3)

0.835

0.361

110 (8.6)

14 (11.7)

1.277

0.258

Whether received higher education (n, %)

1081 (80.3)

132 (80.5)

0.003

0.957

922 (72.1)

91 (75.8)

0.770

0.380

Gender (man, n, %)

702 (52.1)

103 (62.8)

6.662

0.010

711 (55.6)

58 (48.3)

2.334

0.127

Gestational age (weeks x ± s)

39.5 ± 1.0

39.2 ± 1.1

1.645

0.100

39.3 ± 1.0

39.4 ± 1.0

-1.210

0.227

Weight of birth (g x ± s)

3362 ± 396

3416 ± 415

-1.644

0.100

3462 ± 447

3542 ± 473

-1.850

0.065

Feeding method (n, %)

10.846

0.004

1.336

0.113

 Breast feeding

1060 (78.7)

138 (84.1)

963 (75.2)

96 (80.0)

 Artificial feeding

12 (8.9)

5 (3.0)

24 (1.8)

2 (1.7)

 Mixed feeding

274 (20.4)

21 (12.8)

292 (22.8)

22 (18.3)

Whether used antibiotics in infant (n, %)

92 (6.8)

68 (41.4)

185.044

 < 0.001

99 (7.7)

46 (38.3)

110.521

 < 0.001

Incidence of atopic dermatitis in 2 years children (n, %)

150 (11.1)

75 (45.0)

140.204

 < 0.001

163 (12.7)

9 (7.5)

3.370

0.185