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Table 2 Risk factors for infant mortality, by Indigenous status

From: Determinants of infant mortality for children of women prisoners: a longitudinal linked data study

 

Indigenous infants (n = 25,962)

Non-Indigenous infants (n = 16,712)

Survived

Died

Survived

Died

n

n

%

RR

(95% CI)

p-value

n

n

%

RR

(95% CI)

p-value

Infants

25,532

430

1.7

   

16,596

116

0.7

   

Demographic factors

Sexa

            

Male

13,052

240

1.8

1.20

(0.99–1.45)

0.058

8586

64

0.7

1.14

(0.79–1.65)

0.468

Female*

12,438

190

1.5

   

7991

52

0.6

   

Maternal Indigenous status

Indigenous

24,321

418

1.7

1.72

(0.97–3.05)

0.062

      

Non-Indigenous*

1211

12

1.0

   

16,596

116

0.7

   

Socioeconomic statusb

Very low (0–5%)

6793

128

1.8

2.16

(1.38–3.39)

0.001

996

15

1.5

3.50

(1.88–6.54)

<.001

Low (6–25%)

11,095

195

1.7

2.02

(1.30–3.13)

0.002

4461

50

1.1

2.62

(1.65–4.15)

<.001

Medium (26–50%)

5054

83

1.6

1.89

(1.18–3.01)

0.008

4517

23

0.5

1.20

(0.69–2.07)

0.523

High (51–100%)*

2546

22

0.9

   

6584

28

0.4

   

Geographical remotenessc

Major cities/Inner regional*

10,331

160

1.5

   

13,574

88

0.6

   

Outer regional

4185

73

1.7

1.12

(0.85–1.48)

0.404

1811

22

1.2

1.86

(1.17–2.97)

0.009

Remote

4776

75

1.5

1.01

(0.77–1.33)

0.922

834

5

0.6

0.93

(0.38–2.27)

0.865

Very remote

6195

120

1.9

1.25

(0.98–1.58)

0.066

326

< 5

0.3

0.47

(0.07–3.40)

0.458

Baseline Pregnancy Risk Factors

Multiple gestation

Yes

568

23

3.9

2.43

(1.61–3.66)

<.001

414

13

3.0

4.81

(2.73–8.50)

<.001

No*

24,964

407

1.6

   

16,182

103

0.6

   

Birth spacing

< 18 months

3011

82

2.7

1.74

(1.37–2.21)

<.001

1112

19

1.7

2.70

(1.66–4.40)

<.001

Firstborn/18 months+*

22,521

348

1.5

   

15,484

97

0.6

   

Maternal age

12–19 years

7628

122

1.6

0.91

(0.72–1.17)

0.471

1740

21

1.2

2.36

(1.41–3.94)

0.001

20–24 years

9420

158

1.6

0.96

(0.76–1.20)

0.713

3916

47

1.2

2.35

(1.57–3.52)

<.001

25–34 years*

7533

132

1.7

   

9054

46

0.5

   

35 + years

951

18

1.9

1.08

(0.66–1.76)

0.761

1886

< 5

0.1

0.21

(0.05–0.86)

0.030

Parity

Nulliparous

9035

126

1.4

0.82

(0.66–1.03)

0.093

7954

53

0.7

0.99

(0.67–1.45)

0.939

Parity 1–2*

10,847

184

1.7

   

7539

51

0.7

   

Parity 3+

5650

120

2.1

1.25

(0.99–1.57)

0.058

1103

12

1.1

1.60

(0.86–2.99)

0.140

Pregnancy complications

Abruptio placentae and other disordersd

Yes

122

8

6.2

3.77

(1.91–7.42)

<.001

90

< 5

4.3

6.31

(2.38–16.8)

<.001

No*

25,410

422

1.6

   

16,506

112

0.7

   

Placenta previa

Yes

87

< 5

3.3

2.02

(0.66–6.17)

0.217

109

0

0

   

No*

25,445

427

1.7

   

16,487

116

0.7

   

Premature rupture of membranes

Yes

1200

34

2.8

1.72

(1.22–2.43)

0.002

445

5

1.1

1.63

(0.67–3.97)

0.284

No*

24,332

396

1.6

   

16,151

111

0.7

   

Infection related hospitalisation in pregnancye

Yes

2041

34

1.6

0.99

(0.70–1.40)

0.947

388

< 5

0.5

0.73

(0.18–2.96)

0.664

No*

23,491

396

1.7

   

16,208

114

0.7

   

Other maternal factors/Exposures during pregnancy

Substance use related service contactf

Yes

397

15

3.6

2.24

(1.35–3.72)

0.002

293

6

2.0

2.99

(1.33–6.76)

0.008

No*

25,135

415

1.6

   

16,303

110

0.7

   

Hospitalisation for external causes of injuryg

Yes

1479

38

2.5

1.56

(1.12–2.17)

0.008

278

< 5

1.1

1.55

(0.50–4.86)

0.450

No*

24,053

392

1.6

   

16,318

113

0.7

   

Mental health related service contacth

Yes

768

12

1.5

0.93

(0.52–1.64)

0.794

427

5

1.2

1.70

(0.70–4.14)

0.244

No*

24,764

418

1.7

   

16,169

111

0.7

   

Sibling in contact with child protectioni

Yes

852

30

3.4

2.13

(1.48–3.07)

<.001

237

6

2.5

3.70

(1.64–8.33)

0.002

Firstborn/No*

24,680

400

1.6

   

16,359

110

0.7

   
  1. *Reference category
  2. a42 Indigenous and 19 non-Indigenous infants missing sex
  3. b46 Indigenous and 38 non-Indigenous infants missing socioeconomic status
  4. c47 Indigenous and 51 non-Indigenous infants missing remoteness
  5. dExcludes placenta previa
  6. eInfection related hospitalisation in pregnancy
  7. fSubstance use (including alcohol) or poisoning related service contact (hospital or mental health service)
  8. gHospitalisation for external causes of injury in pregnancy (excludes poisoning)
  9. hMental health service contact in pregnancy (excludes substance use) (hospital or mental health service)
  10. iOlder sibling(s) in contact with child protection system in infant’s pregnancy