Published by Oxford University Press on behalf of the International Epidemiological Association
Ó The Author 2006; all rights reserved. Advance Access publication 4 December 2006
International Journal of Epidemiology 2006;35:1563–1569
doi:10.1093/ije/dyl212
PAEDIATRIC EPIDEMIOLOGY
Sudden Infant Death Syndrome and the time
of death: factors associated with night-time
and day-time deaths
PS Blair,1* M Ward Platt,2 IJ Smith3 and PJ Fleming1 and the CESDI SUDI Research Group
Accepted
24 August 2006
Objective
To investigate the diurnal occurrence of Sudden Infant Death Syndrome (SIDS)
and interaction with established risk factors in the infant sleeping environment.
Methods
A 3 year population-based case–control study, in five English Health Regions.
Parentally defined day-time or night-time deaths of 325 SIDS infants and
reference sleep of 1300 age-matched controls.
Results
The majority of SIDS deaths (83%) occurred during night-time sleep, although
this was often after midnight and at least four SIDS deaths occurred during every
hour of the day. The length of time from last observed alive until the discovery
of death ranged from ,l to 14 h but was not significantly different from the
corresponding sleep period amongst the controls. Amongst the day-time deaths,
38% of the infants were observed alive 30 min prior to discovery and 9% within
10 min. The risk of placing infants asleep on their side was more marked for
day-time deaths (interaction: P 5 0.0001) nearly half of whom were found
prone, while the risk associated with paternal smoking [OR 5 3.25 (95%CI:
1.88–5.62)] was more marked for night-time deaths (interaction: P 5 0.02). The
adverse effect of unsupervised sleep recognized for night-time practice [OR 5
5.38 (95%CI: 2.67–10.85)] was also significant for day-time sleep [OR 5 10.57
(95%CI: 1.47–75.96)]. Significantly more (P 5 0.002) unobserved SIDS infants
(24.8%) were found with bedclothes over the head compared with those SIDS
infants where a parent was present in the room (11.3%).
Conclusions SIDS can happen at any time of the day and relatively quickly. Parents need to
be made aware that placing infants supine and keeping them under supervision
is equally important for day-time sleeps.
Keywords
SIDS, time of death, interval until discovery, sleeping position, smoking, sleeping
in a separate room, supervision
Sudden Infant Death Syndrome (SIDS) predominantly occurs
during infant sleep periods and common infant care practices
associated with this environment have been established as
having an adverse or beneficial effect. However the infant
1
2
3
Institute of Child Life and Health, Department of Clinical Science, South
Bristol, University of Bristol, UK.
Newcastle Neonatal Service, Royal Victoria Infirmary, Newcastle Upon
Tyne, UK.
Nuffield Institute for Health, Leeds, UK.
* Corresponding author. Institute of Child Life and Health, St Michael’s
Hospital,
Southwell Street,
Bristol
BS2
8EG,
UK.
E-mail:
[email protected]
sleeping environment and associated practices during the night
are often different from those during the day, which may have
implications both in terms of the specific advice we give to parents
and the presumed mechanisms that lead to death. Few studies are
sufficiently large to investigate these two different environments,
and, consequently, the advice given to parents1,2 tends to be
centred on the parental bedroom and night-time sleep.
Recent reports from New Zealand and the Nordic countries
suggest that diurnal variations in major risk factors for SIDS
may signify different causal mechanisms; prone sleep position
was more strongly associated with SIDS occurring during
day-light hours, while night-time deaths were more strongly
associated with co-sleeping, maternal smoking, alcohol and
1563
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INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
drug consumption, infant illness, and the non-prone sleeping
position.3–5
Characteristically SIDS deaths occur in unobserved infant
sleep periods, even for day-time deaths. The exact time of death
is unknown and an estimation cannot be determined at
post-mortem. The typical picture has been described as an
apparently well infant being put to bed in the evening and
found dead the following morning, although there is some
evidence that many of the deaths may occur in the latter part
of the night sleep.6 Establishing the interval between last
observation and discovery of the death, especially short
intervals, is becoming increasingly important to validate
potential mechanisms of causality and to understand the
significance of why some risk factors are specifically associated
with night-time or day-time deaths. Unusually long intervals
may suggest poor parental practice although, to our knowledge,
this has not been reported as a controlled observation.
The study of Sudden Unexpected Deaths in Infancy (part of
the Confidential Enquiry into Stillbirths and Deaths in Infancy:
CESDI SUDI study) was designed to elicit detailed information
on the epidemiology and current risk factors associated with
SIDS after the ‘Back to Sleep’ campaign in 1991 and subsequent
fall in rates. This is a report of the temporal characteristics of
the last sleep and risk factors associated with parentally defined
day-time and night-time deaths of SIDS infants compared with
the reference sleep of age-matched controls.
Methodology
The methodology of the CESDI SUDI study has been described
previously.7 Briefly, it was a large population-based case–
control study conducted over a 3-year period from 1993 to
1996. The study aimed to include all SUDI cases aged 7–364
days from five former Health Regions in England (Northern,
South-West, Trent, Wessex and Yorkshire), a total study
population of 17.7 million. Parental data were collected on a
standard questionnaire by research interviewers and from
parent-held and medical records. Bereaved families were visited
within hours of the death for a narrative account and a second
visit within 2 weeks to complete the questionnaire. Four
age-matched control infants for each case were selected. The
interviewer visited each control family within a week of the
death to collect the same data as for the index case. A period of
‘day-time’ or; ‘night-time’ sleep described as the ‘reference
sleep’ was identified in the 24 h prior to the control interview
corresponding to whether the death occurred during the day or
night according to the index parents. Most of the control
interviews were conducted on weekdays; thus, the control
infants were matched for the month and time of day the death
occurred but not the day of the week.
Cause of death was established by a multi-disciplinary
committee after a full paediatric autopsy to a standard protocol.
All deaths were classified according to the Avon clinicopathological system.7,8 This approach has now been recommended nationally when a sudden unexpected death occurs.9
Variable definition
The time the death was discovered or control infant woke was
taken as a precise point in time from the parent. The last
observation was defined as the last time the parents heard or
saw their baby alive before discovery of the death or the control
infant woke. Position put down was the sleeping position the
SIDS infant was put down for the final sleep before being
discovered dead or the reference sleep of the control infant in
the 24 h prior to interview. Infants described as ‘bed-sharing’
were those found after the last sleep co-sleeping with at least
one parent (on a mattress, sofa, or chair). Infants described as
sleeping in ‘another room’ were those infants sleeping outside
the parental bedroom at night or unsupervised in a room
during a daytime sleep. Infant health prior to the last sleep was
determined using a modified form of the Cambridge ‘Baby
Check’, a previously validated system10,11 used to quantify the
degree of infant illness.
Statistical methodology
Data that were not normally distributed were described by
using medians and inter-quartile ranges (iqr) and the
Mann–Whitney test (two sided) was used to test differences
between these distributions. Median point estimates of time
were calculated assuming a 24 h distribution from 1 a.m. to
12 p.m. Odds ratios, 95% confidence intervals and P-values
were calculated, taking into account matching, with conditional logistic regression by using the statistical package SAS.
The factors adjusted for in the multivariate model were all
significant in the univariate and multivariate analyses at the
5% level after stepwise logistic regression. The covariates
included infant factors (age, birth centile, gender, and
gestational age), family factors (young maternal age, unemployment, and family size), and previously identified risk
factors that may interact with day and night sleep (sleeping
position put down, parental proximity in terms of sharing the
same room or the same sleep surface, parental smoking and
taking of illegal drugs, recent maternal alcohol consumption,
head covering, and recent infant illness).
Because of the time lag to arrange interviews the control
infants were about 10 days older than the index infants. The
variable for infant age was, therefore, included in all univariate
and multivariate analyses. For the analysis of night-time and
day-time sleeps the data are presented separately but the
interaction was constructed by including the multiplicative
term of two factors for the whole dataset. The sometimes large
odds ratios given for the day-time deaths reflect the small
numbers in the comparison groups and should be interpreted
in the context of the large confidence intervals also provided.
Results
(i) Characteristics of infant sleep
We asked the parents whether their baby died during what
they considered their night-time or day-time routine; 83%
(270/325) responded that the death occurred during the night
sleep and 17% (55/325) responded during the day. An attempt
was made to match the control reference sleep to a similar daytime/night-time dichotomy and was to a large extent successful
(93.0% successful matching). The proportion of controls with a
day-time reference sleep was 16% (205/1300).
Figure 1 shows the distribution of the times at which the
SIDS deaths were discovered or the control infants awoke. The
SIDS AND THE TIME OF DEATH
1565
%
25
20
SIDS (N=321)
15
Controls (N=1299)
10
5
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Nearest hour of the day the SIDS infant was discovered or the control infant woke (24 hr clock)
Figure 1 The time the SIDS death was discovered or controls awoke (to the nearest hour)
matching produced distributions that were similar in shape
although fewer control infants woke during the evening period
and more tended to wake in the morning at an earlier time
than when the deaths were discovered. The median time SIDS
deaths were discovered [8.30 a.m. (iqr: 7.00–11.10 a.m.)] was
90 min later (P , 0.0001) than the median time control infants
woke [7.00 a.m. (iqr: 5.45–8.30 a.m.)]. This difference was
slightly more marked during weekends and amongst the more
deprived families (social classes IV, V, and the unemployed) but
was still significantly different (P , 0.0001) during weekdays
and amongst the less deprived families. SIDS infants found in
the co-sleeping environment tended to be discovered earlier
[median 5 7.30 a.m. (iqr: 5.50–8.50 a.m.)] than solitary
sleeping SIDS infants [median 9.00 a.m. (iqr: 7.25–12.45 a.m.)]
but this was still significantly later (P 5 0.002) than when the
corresponding co-sleeping controls awoke from reference sleep
[median 5 6.30 a.m. (iqr: 4.40–8.00 a.m.)]. Half of the SIDS
infants (51%) were discovered during the morning hours
(5.30 a.m. to 9.30 a.m.) although at least four SIDS deaths
occurred during every hour of the 24 h day.
The median age of those SIDS deaths occurring during the
night sleep [84 days (iqr: 53–141 days)] was over a month less
(P 5 0.001) than those SIDS deaths occurring during a day-time
sleep [120 days (iqr: 85–184 days)]. Notably the median age of
the co-sleeping SIDS infants [59 days (iqr: 33–100 days)], a
practice which predominantly occurs during the night, was
much less than those SIDS infants who slept alone [112 days
(iqr: 69–169 days)]. Restricting the age comparison of day-time
and night-time deaths to the solitary sleeping SIDS infants
yielded no significant difference (P 5 0.10).
The length of time from last seen or heard alive until
discovery of the night-time death ranged from less than an
hour to 14 h (Figure 2). The median interval for the SIDS
infants was 4 h 45 min (iqr: 2h 30 min—7 h 15 min), slightly
less than the corresponding interval for the controls, 5 h 5 min
(iqr: 3–8 h), and not quite significant (P 5 0.054). Of the 270
parentally defined night-time deaths, 29.1% were last observed
alive between 6 p.m. and prior to midnight, 46.1% between
midnight and prior to 4 a.m., and 24.8% from 4 a.m. onwards.
A fifth of the SIDS infants (20.1%) were observed alive within
2 h before discovery of the night-time death, 11.4% within an
hour, and 6.8% within 30 min. At last observation 78.7% of
the night-time SIDS infants were described by the parents as
apparently healthy.
Figure 3 shows this time interval was much shorter for
day-time sleeps, for both SIDS infants and controls. The median
time from when the SIDS infants were last seen or heard alive
until they were discovered dead after a day-time sleep was 1 h
15 min (iqr: 28 min–1 h 35 min), slightly longer than the time
until the controls awoke, 50 min (iqr: 30 min–1 h 30 min), but
again not significantly different (P 5 0.22).
For day-time sleeps, 37% (69/186) of control infants and
38% of the SIDS infants (20/53) had been checked within
30 min of waking or being found dead. For 9% (5/53) of SIDS
infants, and 11% (21/186) of controls this interval was 10 min
or less. At last observation 78.2% of the day-time SIDS infants
were described by the parents as apparently healthy.
Interaction with day-time or night-time sleep
Table 1 lists risk factors investigated for an interaction with
day-time or night-time sleep.
The interaction between the position in which the infant was
placed for sleep and whether this was a day-time or night-time
sleep was significant (P 5 0.0003), although this was largely due
to infants being placed on their side (interaction: P 5 0.0001)
rather than prone (P 5 0.40). The risk of placing infants on
their side was not significant at night when controlled for other
covariates in the multivariate model (P 5 0.11) but was
significant during the day (P 5 0.003). Of those SIDS infants
put down on their side to sleep at night 30% were found prone
compared with 45% during the day, although this did not
reach significance (P 5 0.19). Most of the control infants (97%)
put down on their side were usually put down in that position;
however, the corresponding proportion was 86% for night-time
deaths and 75% for day-time deaths.
Co-sleeping was a significant risk for both night-time and
day-time sleep as was infants sleeping in a different room from
their parents. This latter practice, which occurs in a quarter of
the control population at night-time, is the most common
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INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
%
14
12
SIDS (N=264)
10
Controls (N=1076)
8
6
4
2
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Length of time from when infant last seen/heard and time SIDS infant was discovered or the control infant woke
from what the parents described as a 'night-time' sleep
Figure 2 Length of time until SIDS discovered or controls awoke (Night) (Nearest hour from time last seen/heard until discovered)
%
60
50
SIDS (N=53)
Controls (N=186)
40
30
20
10
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Length of time from when infant last seen/heard and time SIDS infant was discovered or the control infant woke
from what the parents described as a 'day-time' sleep
Figure 3 Length of time until SIDS discovered or controls awoke (Day) (Nearest hour from time last seen/heard until discovered)
practice during the day, 64% of the day-time control reference
sleeps and 75% of the day-time deaths occurring in an
unsupervised room. Notably 31.0% of SIDS infants sleeping
separately from the parental bedroom were found with
bedclothes over their head compared with 14.8% by the
parental bed and 7.5% who slept in the parental bed. Similarly
13.2% of SIDS infants found after an unsupervised day-time
sleep were found with head covering compared with none of the
supervised SIDS infants. Overall 24.8% (27/109) of unsupervised SIDS infants were found with head covering compared
with 11.3% (22/194) where the parent was present (P 5 0.002).
The prevalence of maternal smoking during pregnancy was
higher amongst mothers of infants who died during the night
although there was no significant interaction. There was,
however, a significant interaction with habitual paternal smoking,
which carried a significant risk for night-time deaths (P , 0.0001)
but not for those deaths that occurred during the day (P 5 0.89).
There was no significant multivariate interaction with other
risk factors in the sleeping environment such as maternal
alcohol consumption (P 5 0.63), parental use of illegal drugs
(P 5 0.78), recent infant illness (P 5 0.63), or head covered by
bedding (P 5 0.77).
Discussion
Although SIDS victims are often discovered after a night-time
sleep the death can occur during any hour of the day and relatively quickly. Three-quarters of the infants who died during
what the parents described as a night-time sleep were still
observed alive after midnight, a fifth were still alive within 2 h of
the final event. Of those who died during the day over a third were
observed alive 30 min prior to death, 9% within 10 min. The fact
that most SIDS parents described their infants as seeming to be
well for this last observation suggests at least for some of these
deaths that the onset of the final event was undetectable or very
quick. For some deaths the time between when the SIDS infant
was last observed alive and found dead seemed very long but was
actually no different from when some of the control infants were
last observed and found after the reference sleep suggesting little
evidence of poor parental practice.
SIDS AND THE TIME OF DEATH
1567
Table 1 Interaction of risk factors with day-time and night-time sleep
Night-time
SIDS
Risk factors
N
Day-time
OR (95% CI)
Controls
%
N
%
a
(Multivariate )
SIDS
P-value
N
Interaction
Controls
%
N
%
OR [95% CI]
Stratum Overall
a
(Multivariate ) P-value
P-value
P-value
0.0003
Position put down
Back
120 45.6
732 67.0
1.00 (Ref)
Side
105 39.9
326 29.9
1.54 (0.91–2.59)
Front
38 14.4
34
3.1
6.20 (2.21–17.40)
21 38.9 163 80.3
0.11 24 44.4
35 17.2
5
1.00 (Ref)
13.43 (2.40–75.05)
0.003
0.0001
2.5
10.35 (1.18–90.80)
0.03
0.40
1.00 (Ref)
0.0005
9 16.7
6 10.9
62 30.4
8 14.5
12
Parental proximity
Same room 103 38.1
b
622 56.8
1.00 (Ref)
Same bed
94 34.8
183 16.7
7.02 (3.54–13.91) ,0.0001
Different
room
73 27.0
290 26.5
5.38 (2.67–10.85) ,0.0001 41 74.5 130 63.7
Maternal smoking
83 31.1
801 73.2
1.00 (Ref)
Yes
184 68.9
293 26.8
2.66 (1.56–4.53)
88 33.0
694 63.4
Yes
179 67.0
400 36.6
No
33 12.7
No
No
1.00 (Ref)
0.25
1.00 (Ref)
2.56 (0.57–11.44)
0.40
0.22
1.00 (Ref)
71 34.8
1.11 (0.24–5.28)
51 92.7 198 97.5
1.00 (Ref)
0.02
0.89
36
0.003
4
7.3
5
2.5 14.34 (0.42–493.49)
0.63
0.14
f
43 16.5
54
4.9
1.95 (0.82–4.61)
47 87.0 192 94.6
0.13
7 13.0
11
5.4
1.00 (Ref)
3.93 (0.24–65.05)
0.78
0.34
g
232 88.2 1050 96.3
31 11.8
40
1.00 (Ref)
3.7
2.85 (1.03–7.89)
209 82.6 1050 96.7
1.00 (Ref)
Head covering
Yes
55 26.8
27 49.1 133 65.2
1.00 (Ref)
217 83.5 1039 95.1
Yes
No
1.00 (Ref)
7.60 (2.54–22.71)
Yes
Infant illness
27 49.1 150 73.2
0.0003 28 50.9
3.25 (1.88–5.62) ,0.0001 28 50.9
3.3
Parental drugs
0.58
0.17
e
226 87.3 1058 96.7
Yes
0.01
0.02
d
No
Maternal alcohol
10.57 (1.47–75.96)
c
No
Paternal smoking
5.9 43.60 (2.31–823.09)
50 90.9 199 97.5
0.04
5
9.1
5
1.00 (Ref)
2.5
0.85 (0.03–25.76)
45 90.0 201 99.0
1.00 (Ref)
0.63
0.92
h
44 17.4
36
3.3 17.43 (6.19–49.14) ,0.0001
5 10.0
2
1.0 14.43 (0.25–841.04)
0.77
0.20
a
Controlling for (i) infant factors: age, birth centile, gender, gestational age, (ii) family factors: young maternal age, unemployment, family size, and (iii) the
above risk factors.
b
Includes co-sleeping in the parental bed, on a sofa, or on a chair.
c
Maternal smoking during pregnancy.
d
Mothers without partners were assumed to be mothers with non-smoking partners.
e
Mothers who consumed more than 2 units of alcohol (equivalent to 1 pint of beer of 2 small glasses of wine) in the 24 h prior to the death or end of control
reference sleep.
f
Parental use of illegal drugs (mainly cannabis) after the birth of the infant.
g
Based on Cambridge Baby Check score of 13 or more (infant ill and requires a doctor).
h
Infant found with head covered by bedding.
Many of the risk factors associated with SIDS were significant for both night-time and day-time deaths, but there
were some important differences. We confirm the significant
interaction between infant sleeping position and day-time
deaths but unlike the New Zealand and Nordic studies the
marked increase in the significance was for infants being put
down on their side rather than prone. The prevalence of being
positioned prone was more marked for day-time sleep but
the interaction was not significant and was not explained by
the difference in the definition of what constitutes a ‘day-time’
or ‘night-time’ sleep between the studies, as it persisted when
we re-analysed our data using the New Zealand3,4 and Nordic
definitions.5 The proportion of infants put down prone were
much higher in these previous studies, which may suggest
that our findings are more synonymous with infant care
practices after the ‘Back to Sleep’ campaign. Although the
prone position is now used infrequently12,13 the side
positioning is still commonly used,14 especially amongst
pre-term infants after hospital discharge15 and amongst
bed-sharing infants.16 Placing infants on their side to sleep
was the most common practice amongst SIDS infants who
died during the day in our study, almost half of them
were found prone and a quarter were not usually placed in
this position. The key message from all of these studies is to
place the infant supine for day-time as well as night-time
sleeps.
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Co-sleeping, recent maternal alcohol consumption, and
parental use of illegal drugs were more marked during night-time
deaths, but, unlike the New Zealand study, we did not find any
significant interaction. Co-sleeping infants tended to be discovered dead earlier than solitary sleeping SIDS infants, although the
bed-sharing control infants also woke from the reference sleep
significantly earlier than the control infants who slept elsewhere.
The finding that SIDS infants found after a night sleep were
significantly younger than those found in the day appears to be a
feature of co-sleeping rather than night-time sleeps.17,18
Previous findings of a lower SIDS risk if infants share the same
room but not the same bed as the parents19,20 has led to current
advice that parents should put the infant cot by the parental bed
for at least the first 6 months.1,2 This analysis suggests that the
risk associated with the absence of parental supervision is also
significant for day-time sleeps, a setting in which it was far more
common for infants to sleep alone in a room and challenges the
assumption of protection being limited to where infants sleep at
night. In particular we found that unsupervised SIDS infants
were more likely to be found with bedclothes covering their
head. Parental presence during infant sleep does not guarantee
the infant is being constantly observed, indeed this is not usually
the case and SIDS can also occur under closely monitored
conditions.21 However, having the sleeping infant nearby
during the day may alert parents to circumstances such as
infants rolling from the side to the prone position or bedclothes
covering the infant head or face. In conjunction with this
parents also need to be made aware of the risks associated with
inappropriate sleeping environments for young infants during
day-time naps such as car seats.22
The prevalence of maternal smoking during pregnancy was
higher amongst the mothers of SIDS infants discovered after
the night-sleep compared with those discovered during the day,
but the interaction was not significant. We did, however, find a
significant interaction with paternal smoking, which was not a
significant risk for those infants who died during the day but
highly significant for infants who died at night. These findings
are in the same direction as the New Zealand and Nordic
studies and potentially support previous indications of a strong
link between prenatal and post-natal infant exposure to
tobacco smoke and co-sleeping.17,18,23,24
The significant interactions found in other studies between
infant illness, sweating, and colds with night-time sleep was
not confirmed in this study neither was an interaction found
with head covering and period of sleep.
The SIDS deaths were discovered on average 90 min later
than when the control infants woke. This does not appear to be
explained by socioeconomic status nor any differences in
practice between weekdays or weekends. Recall bias in unlikely
as most of the SIDS mothers were interviewed within hours of
the death. This difference between discovery and waking could
be related to patterns of parental sleep, as we have previously
reported that SIDS parents in general went to bed later than
the controls.7 Although this finding could be an artefact of
comparing sleeping infants to dead ones, a unique study of
sleep recordings obtained from infants who subsequently
died of SIDS showed decreased waking time during the
early morning.25 Another study comparing SIDS deaths
with near-miss SIDS found that the latter were discovered
and rescued earlier than those infants who died, suggesting
that the lack of observation could be a key factor in these
deaths.26
We conclude that although SIDS commonly occurs unobserved
during night-time sleep, the onset of the final event can occur
relatively quickly and at any time of the day. There are important
differences between sleeping during night and day that may
reflect a different diurnal pathogenesis for sudden infant deaths.
Current advice on reducing risk should emphasize that placing
infants supine for sleep, and keeping them under supervision, is
important both by night and day.
Acknowledgements
Funding was provided for these studies by grants from: (i) The
Foundation for the Study of Infant Deaths (FSID); (ii) Babes in
Arms; (iii) The Confidential Enquiry into Stillbirths and Deaths in
Infancy. This manuscript is only being submitted to the
International Journal of Epidemiology and will not be submitted
elsewhere while under consideration. All authors are responsible
for the reported research and have participated in the concept and
design; analysis and interpretation of data; drafting of the
manuscript; and have approved the manuscript to be submitted.
None of the authors have any conflict of interest. The references
have been checked for accuracy and completeness. Professor
P.J.F. will act as guarantor for the paper.
KEY MESSAGES
SIDS is predominantly an unobserved event that occurs during night-time and day-time infant sleep.
The length of time from last parental observation of a seemingly well infant until the discovery of death was
sometimes quite short suggesting that the onset of the final event for some deaths was undetectable or very quick.
The possible protective effect of having an adult in the same room as the sleeping infant during the night is
equally applicable for day-time deaths and may reduce the risk of young infants rolling prone or bedclothes
covering the infant head.
Most risk factors associated with SIDS were significant for both night-time and day-time deaths although
paternal smoking was only significant for night-time deaths and placing infants on their side to sleep was more
marked amongst the day-time deaths.
SIDS AND THE TIME OF DEATH
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