Table 1 Characteristics of CHILD cohort study participants included in the current analysis with and without CBCL scores at 5 years

Breastfeeding Practices

Breastfeeding mode 3 months

2264

756

 No breast milk (i.e. formula only)

281

(12.4)

151

(20.0)

< 0.001

 Breast milk and formula

576

(25.4)

215

(28.4)

 Breast milk only (some expressed)

767

(33.9)

209

(27.6)

 Breast milk only (all direct)

640

(28.3)

181

(23.9)

Breastfeeding at 6 months

2305

730

 No breastfeeding (i.e. formula only)

482

(20.9)

241

(33.0)

< 0.001

 Partial breastfeeding

1392

(60.4)

370

(50.7)

 Exclusive breastfeeding

431

(18.7)

119

(16.3)

Breastfeeding at 12 months

2335

815

 No

1225

(52.5)

570

(69.9)

< 0.001

 Yes

1110

(47.5)

245

(30.0)

Breastfeeding at 24 months

2335

815

< 0.001

 No

2114

(90.5)

790

(96.9)

 Yes

221

(9.5)

25

(3.1)

Postpartum Depression

6 months

2032

521

 Score ≥ 16

262

(13.0)

109

(20.9)

< 0.001

1 year

2074

485

 Score ≥ 16

265

(12.8)

105

(21.6)

< 0.001

2 years

1941

298

 Score ≥ 16

305

(15.7)

49

(16.4)

0.75

Parent-Child Dysfunction

1 year

2076

487

 Score ≥ 20 (85th percentile)

383

(13.6)

79

(16.2)

0.14

2 Years

1948

299

 Score ≥ 20 (85th percentile)

281

(14.4)

50

(16.7)

0.30

Child Behaviour Checklist

Internalizing behaviour problems (t-score)

2342

44.6

[9.2]

-

Externalizing behaviour problems (t-score)

2342

39.8

[9.6]

-

Total behaviour problems (t-score)

2342

41.3

[9.2]

-

Confounders

Child sex (female)

2342

1112

(47.5)

927

434

(46.8)

0.73

ADHD genetic risk score

2051

-0.01

[1.0]

649

0.02

[1.0]

0.52

Number of older siblings

2342

926

 None

1239

(52.9)

521

(56.3)

0.20

 One

804

(34.3)

290

(31.3)

 Two or more

299

(12.8)

115

(12.4)

Prenatal stress (range 0–40)

2188

12.3

[6.3]

787

13.2

[6.5]

< 0.001

Prenatal depression

2180

339

 Score ≥ 16

339

(15.6)

167

(21.4)

< 0.001

Smoking during pregnancy

2305

157

(6.8)

860

128

(14.9)

< 0.001

Maternal education (post-secondary degree)

2288

1813

(79.2)

842

577

(68.5)

< 0.001

Maternal race

2331

882

 White

1739

(74.6)

602

(68.3)

< 0.001

 Asian

369

(15.8)

137

(15.5)

 First Nations or Other

223

(9.6)

143

(16.2)

Marital status (married or common law)

2298

2191

(95.3)

858

777

(90.6)

< 0.001

Household income

2289

844

 $0- $29,999

80

(3.5)

64

(7.6)

< 0.001

 $30,000- $59,999

303

(13.2)

116

(13.7)

 $60,000- $99,999

598

(26.1)

183

(21.7)

 $100,000- $150,000 or over

1111

(48.5)

383

(45.4)

 Prefer not to say

197

(8.6)

98

(11.6)

Birth weight (kg)

2290

3.5

[0.5]

900

3.4

[0.5]

0.07

Gestational age (weeks)

2305

39.2

[1.4]

900

39.1

[1.4]

0.04

Birth mode (vaginal)

2308

1734

(75.1)

902

667

(74.0)

0.50

Study site

2342

927

 Winnipeg

724

(30.9)

272

(29.3)

< 0.001

 Toronto

499

(21.3)

274

(29.6)

 Vancouver

568

(24.3)

159

(17.2)

 Edmonton

551

(23.5)

222

(23.9)