Null model

Model 1

Model 2

Model 3

Model 4

Model 5

Model 6

Model 7

Model 8

Model 9

β

P

β

P

β

P

β

P

β

P

β

P

β

P

β

P

β

P

β

P

Intercept

15.2471

<0.001

12.6501

<0.001

12.8187

<0.001

11.28

<0.001

12.7736

<0.001

12.6949

<0.001

12.8078

<0.001

12.6118

<0.001

12.6628

<0.001

12.7622

<0.001

Age 0 year

REF

REF

REF

REF

REF

REF

REF

REF

REF

Age 1.5 year

4.0715

<0.001

3.9414

<0.001

5.5908

<0.001

4.0141

<0.001

4.2522

<0.001

4.2721

<0.001

4.1562

<0.001

3.8118

<0.001

3.7615

<0.001

Age 2 year

3.4631

<0.001

3.3388

<0.001

4.9701

<0.001

3.4098

<0.001

3.3805

<0.001

3.4895

<0.001

3.5224

<0.001

3.3695

<0.001

3.336

<0.001

Age 3 year

3.0416

<0.001

2.9167

<0.001

4.7529

<0.001

3.0082

<0.001

3.3894

<0.001

3.1509

<0.001

3.1085

<0.001

2.9379

<0.001

2.9246

<0.001

Low birth weight vs. ≥2500 g

−2.0189

<0.001

Low birth weight × age 0

REF

Low birth weight × age 1.5

1.4965

<0.001

Low birth weight × age 2

1.4696

<0.001

Low birth weight × age 3

1.4312

<0.001

Preterm vs. others

1.4493

<0.001

Preterm × age 0

REF

Preterm × age 1.5

−1.608

<0.001

Preterm × age 2

−1.5914

<0.001

Preterm × age 3

−1.809

<0.001

First child vs. others

−0.293

0.0355

−0.2926

0.0357

First child × age 0

REF

First child × age 1.5

0.1595

0.259

0.1706

0.2278

First child × age 2

0.1684

0.2201

0.1714

0.2134

First child × age 3

0.1385

0.2973

0.1407

0.2906

Smoking vs. non-smoking mother

−0.0292

0.8934

Maternal smoking × age 0

REF

Maternal smoking × age 1.5

−0.1969

0.4922

Maternal smoking × age 2

0.08705

0.7506