Table 1 Participant characteristics by frequency of infant consumption of yogurt at 1 year of age

Mother’s age at childbirth

Mean ± SD, y

31.6 ± 4.81

31.3 ± 4.83

31.6 ± 4.77

32.1 ± 4.75

Pre-pregnancy BMI, kg/m ²

< 18.5

701

(5.2)

905

(4.4)

1,002

(5.1)

662

(5.8)

18.5 to < 25

10,770

(80.1)

16,409

(79.6)

15,968

(80.6)

9,053

(79.8)

≥ 25

1,972

(14.7)

3,298

(16.0)

2,841

(14.3)

1,629

(14.4)

Parity

Primiparous

4,720

(35.1)

7,256

(35.2)

8,989

(45.4)

6,374

(56.2)

Multiparous

8,723

(64.9)

13,356

(64.8)

10,822

(54.6)

4,970

(43.8)

Highest education level, y

≤ 12

4,392

(32.7)

7,283

(35.3)

6,036

(30.5)

3,202

(28.2)

12 to < 16

5,641

(42.0)

8,826

(42.8)

8,824

(44.5)

5,092

(44.9)

≥ 16

3,410

(25.4)

4,503

(21.9)

4,951

(25.0)

3,050

(26.9)

Annual household income, JPY

< 4 million

5,416

(40.3)

8,399

(40.8)

7,189

(36.3)

3,794

(33.4)

4 to < 6 million

4,533

(33.7)

6,981

(33.9)

6,788

(34.3)

3,792

(33.4)

≥ 6 million

3,494

(26.0)

5,232

(25.4)

5,834

(29.5)

3,758

(33.1)

Marital status

Married

13,262

(98.7)

20,317

(98.6)

19,580

(98.8)

11,195

(98.7)

Divorced or widowed

181

(1.4)

295

(1.4)

231

(1.2)

149

(1.3)

Alcohol intake

Never

12,323

(91.7)

18,761

(91.0)

18,251

(92.1)

10,550

(93.0)

Former

563

(4.2)

944

(4.6)

870

(4.4)

467

(4.1)

Current

557

(4.1)

907

(4.4)

690

(3.5)

327

(2.9)

Smoking history

Never

8,241

(61.3)

12,195

(59.2)

12,324

(62.2)

7,327

(64.6)

Quit

4,764

(35.4)

7,645

(37.1)

6,930

(35.0)

3,767

(33.2)

Current

438

(3.3)

772

(3.8)

557

(2.8)

250

(2.2)

Employed

No

7,272

(54.1)

10,210

(49.5)

10,164

(51.3)

6,179

(54.5)

Yes

6,171

(45.9)

10,402

(50.5)

9,647

(48.7)

5,165

(45.5)

Cesarean section

No

10,928

(81.3)

16,989

(82.4)

16,170

(81.6)

9,129

(80.5)

Yes

2,515

(18.7)

3,623

(17.6)

3,641

(18.4)

2,215

(19.5)

Gestational weeks

Mean ± SD, weeks

39.3 ± 1.55

39.3 ± 1.44

39.3 ± 1.46

39.3 ± 1.47

Birth weight

Mean ± SD, kg

3035 ± 413.5

3036 ± 402.9

3028 ± 402.9

3016 ± 403.5

Infant sex

Male

6,987

(52.0)

10,324

(50.1)

10,048

(50.7)

5,922

(52.2)

Female

6,456

(48.0)

10,288

(49.9)

9,763

(49.3)

5,422

(47.8)

Major congenital anomaly

No

13,150

(97.8)

20,176

(97.9)

19,364

(97.7)

11,074

(97.6)

Yes

293

(2.2)

436

(2.1)

447

(2.3)

270

(2.4)

Birth season

Spring (months 3–5)

3,000

(22.3)

4,782

(23.2)

4,756

(24.0)

2,731

(24.1)

Summer (months 6–8)

3,381

(25.2)

5,551

(26.9)

5,488

(27.7)

3,228

(28.5)

Fall (months 9–11)

3,856

(28.7)

5,664

(27.5)

5,341

(27.0)

2,969

(26.2)

Winter (months 12–2)

3,206

(23.9)

4,615

(22.4)

4,226

(21.3)

2,416

(21.3)

Night crying at 1 year of age

No

6,827

(50.8)

10,679

(51.8)

10,150

(51.2)

5,883

(51.9)

Yes

6,616

(49.2)

9,933

(48.2)

9,661

(48.8)

5,461

(48.1)

Nursery attendance at 1 year of age

No

9,874

(73.5)

14,157

(68.7)

14,727

(74.3)

9,094

(80.2)

Yes

3,569

(26.6)

6,455

(31.3)

5,084

(25.7)

2,250

(19.8)