Table 1. Maternal, family, and infant characteristics
Maternal age at birth (years)
Maternal prioritized ethnicity
European
Māori
Otherc
Total (n)
209
209
-207
206
209
209
208
207
162
208
206
209
209
207
209
209
-
n (%)
177 (84.7)
15 (7.2)
17 (8.2)
9 (4.4)
113 (54.6)
57 (27.5)
28 (13.5)
14 (6.8)
41 (19.9)
29 (14.1)
122 (59.2)
120 (57.4)
33 (15.8)
7 (3.4)
49 (23.4)
193 (92.8)
10 (4.8)
5 (2.4)
74 (35.9)
93 (45.2)
39 (18.9)
20 (9.6)
80 (38.3)
92 (44.0)
17 (8.1)
0.88b
162 (77.5)
24 (11.5)
23 (11.0)
Mean (SD)
31.5 (5.0)
2 (1)a
6.8 (4)
12.7 (3.4)
0 (1)
40.0 (1.3)
3522 (484)
-
Maternal BMI (pre-pregnancy) categories
Underweight
Healthy
Overweight
Obese
Maternal education
Year 11 or lower
Year 12 or 13
Post-secondary
Degree or higher
Maternal employment
Working (full-time, part-time, or casual)
Maternity leave (paid or unpaid)
Student (and possibly working)
Not working (includes carers)
Parity
Maternal EPDS
Maternal Stress
Maternal AUDIT-C
Living arrangements
With child’s father/partner
With family
Other
NZDep2006
1-3 (low deprivation)
4-7
8-10 (high deprivation)
Family income (NZDd)
≤$30,000
-$70,000
Over $70,000
Not provided
Gestation (weeks)
Birth weight (g)
Infant sex (M:F)
Infant prioritised ethnicity
European
Māori
Otherc
a
median (IQR)
b
ratio
c
Other includes Pacific, Asian, Middle Eastern, Latin American, African
d
NZD, New Zealand dollars. $70,000 represents average annual household income in region
Unless otherwise stated, maternal and family data were collected at baseline (third trimester)
Table 2. Data source for SUDI Risk score and the number of infants in this study following best practice
Best practice
Risk factor
Data Source
Supine sleep position
Prone or side sleep
position
Gilbert et al, 2005 (15)
Risk score
Odds ratio (95% C.I.)
6.91 (4.63-10.32)
Any breastfeeding
No breastfeeding
Hauck et al, 2011 (18)
Usual pacifier use
No pacifier use
Hauck et al, 2005 (19)
Current Study
Age (weeks) n
19
195
Following best practice, n (%)
Yes
No
176 (90.3)
19 (9.7)
2.63 (1.85-3.7)a
8.7c
199
178 (89.4)
21 (10.6)
1.41 (1.12-1.69)b
19
194
36 (18.6)
158 (81.4)
No bed sharing &
No maternal smoking
in pregnancy
a
b
unadjusted odds ratios
adjusted odds ratios
37 (19.4)
No bed sharing &
Maternal smoking
in pregnancy
Carpenter et al, 2004 (16)
1.98b
3
191
Bed sharing &
No maternal
smoking in
pregnancy
Vennemann et al, 2012 (17)
1.66 (0.91-3.01)b
-
Bed sharing &
Maternal smoking
in pregnancy
Vennemann et al, 2012 (17)
6.27 (3.94-9.99)b
-
154 (80.6)
12 (6.3)
-
-
24 (12.6)
-
-
1 (0.5)
Table 3. Predictors of SUDI risk scores
Predictor
Maternal age at birth (years)
Fractional polynomial transformed
predictors
20
25
30
35
40
Linear predictor
Maternal prioritized ethnicity
European
Māori
Other
Maternal BMI pre-pregnancy (per unit)
Maternal education
Year 11 or lower
Year 12 or 13
Post-secondary
Degree or higher
Maternal employment
Not working
Full-time, part-time, casual
Parity (per birth)
EPDS (per point)
Stress (per point)
AUDIT-C (per point)
Living arrangements
Without partner or family
With partner
With family
NZDep2006 (per decile)
n
176
176
174
173
176
176
175
175
140
176
173
Unadjusted
Ratio of
geometric
means
95% CI
1.00
0.23
0.16
0.16
0.17
1.00
1.79
0.98
1.01
1.00
0.50
0.39
0.33
1.00
0.64
1.15
1.06
1.02
0.97
1.00
1.35
1.55
1.02
0.12–0.44
0.07–0.34
0.08–0.33
0.09–0.34
1.12–2.88
0.67–1.43
0.99–1.03
0.31–0.80
0.23–0.64
0.21–0.51
0.52–0.79
1.05–1.27
1.03–1.09
0.99–1.06
0.84–1.11
0.57–3.19
0.56–4.28
0.97–1.06
P-value
< 0.001
0.053
0.297
< 0.001
0.001
0.004
< 0.001
0.177
0.657
0.697
0.489
Adjusted a (n=170)
Ratio of
geometric
means
95% CI
P-value
0.97
1.00
1.21
0.92
1.00
0.61
0.52
0.52
1.00
0.79
1.13
1.03
1.01
-
0.95–1.00
0.75–1.95
0.64–1.32
0.37–1.00
0.31–0.87
0.33–0.83
0.64–0.98
1.01–1.26
1.00–1.06
0.98–1.05
-
0.030
0.649
0.042
0.031
0.028
0.036
0.353
-
Family income (NZDb)
176
≤$30,000
1.00
-$70,000
0.93
0.62–1.39
Over $70,000
0.62
0.41–0.92
Not provided
1.39
0.81–2.37
Gestation (per week)
176
0.98
0.90–1.07
Infant sex
176
Girl
1.00
Boy
0.88
0.70–1.10
a
Adjusted for all other variables in the model
b
NZD, New Zealand dollars. $70,000 represents average annual household income in region
Unless otherwise stated, maternal and family data were collected at baseline (third trimester)
< 0.001
0.708
0.246
-
1.00
0.94
0.77
1.38
1.00
0.90
0.63–1.41
0.51–1.17
0.80–2.38
0.73–1.10
0.062
0.283
-