The Evidence

Ed Mitchell

Department of Paediatrics, University of Auckland

Auckland, New Zealand

9 October 2013

MoH Safe Sleep – How to protect your baby:

• Put your baby to sleep on their back with their face up.

• Ensure your baby’s face is clear of bedding and they can’t get trapped or strangled. Avoid using pillows and bumper pads; don’t put baby down on soft surfaces; make sure there are no loose blankets; remove any cords from bedding; ensure there are no gaps in their bed. (Unintentional suffocation)

• Your baby is safest in their own bed (a cot, bassinette, wahakura or pepipod) and in the same room as their parent/caregiver (when the parent/caregiver is also asleep). Babies shouldn’t sleep in bed with another person (either adult or child).

• Your baby should be smokefree in the womb and after birth. Also make sure friends and family don’t smoke around baby.

• If possible, breastfeed your baby.

Outline

• Sleeping position• Smokefree• Breastfeeding• Sleeping in the parental bedroom• Bed sharing• Accidental suffocation

Sleeping position

• Overwhelming evidence from case-control studies that prone sleeping position is associated with SIDS

• The recommendation that placing infants to sleep on their back (“Back to Sleep”) has been associated with a dramatic fall in SIDS mortality

• Infant care practice surveys show that few infants are placed prone to sleep

• Thus prone sleeping position as a risk factor has largely been eliminated

Unaccustomed to prone sleeping

Usual Last sleep Cases Controls Adj OR

Non-prone Non-prone 37% 62% 1.0

Prone Non-prone 3% 2% 3.0

Non-prone Prone 8% 1% 19.3

Prone Prone 56% 32% 4.6

• Infants unaccustomed to the prone sleep position are at much greater risk for SIDS when placed prone than if they had been used to prone sleeping.

• It is uncertain why the infants were placed prone, but it does emphasise that all caregivers, such as grandparents, need to know the preferred sleeping position is supine.

Risk of SIDS associated with side sleeping position compared with back

At least 10 published studies

New Zealand, Australia, UK, US, Germany, Scandinavia

Pooled OR=2.0 (95% CI=1.7, 2.4)

Side sleeping position is unstable with infants mostly rolling onto their back, but occasionally rolling onto their front. This has been called “secondary prone”.

Conclusion:

Infants placed supine (back) to sleep are at the lowest risk of SIDS, which supports the recommendation that this is the preferred sleeping position of healthy infants.

Risk of SIDS associated with maternal smoking in pregnancy

• 52 studies prior to “Back to Sleep” campaigns• At least 17 studies since “Back to Sleep”• These come from UK, US, NZ, Germany,

Scandinavia, Netherlands• All showed an increased risk• Pooled OR = 3.9 (3.8-4.1)

Risk of SIDS associated with father’s smoking where the mother is a non-smoker

7 studies

From UK (3), New Zealand (2), Scandinavia (2), Europe (1)

Pooled OR = 1.5 (95% CI = 1.2, 1.8)

Conclusions: Smoking and SIDS

• There is substantial evidence that maternal smoking in pregnancy causes SIDS (OR = 3.9)

• The effect of environmental tobacco smoking (ETS) is small, but statistically significant

• The predominant effect from maternal smoking is likely to be in utero exposure of the fetus

Amount smoked by mother

Amount smoked by the mother

Implications

Using the odds ratios in the DH figure, reducing maternal smoking from 20+ cigarettes per day to 10-19/day lowers the risk by a quarter, whereas getting those who smoke 1-9/day to stop lowers their risk by three quarters.

Breastfeeding and reduced risk of SIDS: A meta-analysis (Hauck et al, 2011)

• Identified 23 studies• Pooled univariate OR = 0.49 (95% CI=0.45-0.53)• However, this might represent confounding by

socioeconomic status• 9 studies reported multivariate risk which included

adjustment for socioeconomic status

Multivariable analysis of any breastfeeding versus no breastfeeding (N=9)

Study or Subgroup

Chen 2004Fleming 1996Hauck 2003Jonville-Bera 2001Mitchell 1997Ponsonby 1995Stray-Pedersen 2005Vennemann 2009Wennergren 1997

Total (95% CI)

Heterogeneity: Chi² = 16.54, df = 8 (P = 0.04); I² = 52%Test for overall effect: Z = 4.80 (P < 0.00001)

log[]

-0.174350.058269-0.91629-0.59784-0.07257-0.15082-1.42712-0.84397

-0.693147

SE

0.1146090.3176570.3195820.3071360.4203370.4012450.86918

0.2393540.21979

Weight

48.3%6.3%6.2%6.7%3.6%3.9%0.8%

11.1%13.1%

100.0%

IV, Fixed, 95% CI

0.84 [0.67, 1.05]1.06 [0.57, 1.98]0.40 [0.21, 0.75]0.55 [0.30, 1.00]0.93 [0.41, 2.12]0.86 [0.39, 1.89]0.24 [0.04, 1.32]0.43 [0.27, 0.69]0.50 [0.33, 0.77]

0.68 [0.58, 0.80]

IV, Fixed, 95% CI

0.01 0.1 1 10 100Favors Breastfeeding Favors Not Breastfeeding

Room sharing

Scragg et al, Lancet 1995

Yes

No

Room sharing last sleep but not bed sharing

Percent exposed

Univariate Multivariate

Author Country Case Control OR (95% CI)

Scragg (1996) New Zealand

20.7 37.1 0.44 0.25

Blair (1999) England 25.3 39.0 0.53 0.51

Hauck (2003) United States

20.8 28.1 0.67 Not reported

Carpenter (2004)

Europe 28.0 44.5 0.49 0.32

Tappin (2005) Scotland 35.8 63.5 0.32 0.31

Conclusion

Room sharing providing the infant is not bed sharing decreases the risk of SIDS 3-fold.

Recommendation

Parent/s should sleep in the same room as baby for first six months.

Definition of co-sleeping and bed sharing

• Co-sleeping and bed sharing were synonymous, however the advocates of co-sleeping have broadened the term to include parents and infants sleeping in close proximity (e.g. room sharing but not bed sharing). Accordingly, this term should be avoided.

• Bed sharing is defined as the parent sleeping with the infant on the same sleeping surface (usually a mattress). A key feature is that the parent is asleep.

Bed sharing in the New Zealand case-control study (1987-1990).

Cases Controls OR

Yes 24.0 10.5 2.7 (2.0, 3.6)

No

Mitchell

76.0

et al, 1992

89.5 1.0

Confirmation that bed sharing is a risk for SIDS SIDS

Vennemann et al, J Pediatrics, 2012

Interaction between maternal smoking and infant bed sharing

Mother Bed Last two Last

smoked sharing weeks sleep

No No 1.0 1.0

Yes No 1.4 1.5

No Yes 1.7 1.0

Yes Yes 3.9 4.6

(Expected 2.4 1.5)

Scragg et al, BMJ 1993

Meta-analysis of bed sharing and risk of SIDS by maternal smoking status

Bed sharing infants who were placed back in their own cot to sleep

• Are not at increased risk (CESDI, Irish)• However, mothers may intend to place their

infant back in own cot, but fall asleep. This may account for why tired mothers and SIDS cases unaccustomed to bed sharing appear to be at higher risk.

• This provides strong evidence that bed sharing is the problem, and not just the characteristics of the families that bed share.

ORs (log scale) for SIDS and 95% CIs of bed-sharing by infant age and mother smoking or not during pregnancyCarpenter et al, Lancet, 2004

Bed sharing when parents do not smoke: Is there a risk of SIDS?

Bob Carpenter et al, BMJ Open 2013)

• Combined data from 5 case-control studies • ECAS (excluding CESDI), 1992 to1996 • Scottish 1996–2000 • New Zealand 1987–1990

• Irish 1994 to 2003• GeSID 1999 to 2003

• 1472 cases and 4679 controls

Bed Sharing Odds Ratios by age for Breast Fed infants

when neither parent or both parents smokeO

dds

Rat

ios

log

scal

e

Estimated ORs 95%CI

Estimated SIDS rate per 1000 live births for selected groups (mother 26-30yrs, 2nd child, birthweight 2500-3499g;

SIDS rate=0.5/1000)

Risk factorFeeding

presentSmoking

Room but not bed sharing

Bed sharing

Ratio of rates

Breast None 0.08 0.23 2.7

Bottle None 0.13 0.34 2.7

Breast Mother 0.13 1.27 9.7

Breast Both parents 0.24 1.88 7.7

Bottle Both parentsplus alcohol

1.77 27.5 16.0

If parents follow our SIDS prevention messages the SIDS rate is very low.

If they bed share but otherwise do the right things the risk is increased almost 3 fold.

The combination of parental smoking, bed sharing AND alcohol is lethal (2.8/100).

If you add other factors the risk becomes even higher:

• Birthweight of 2.25.kg• Mother aged 18 years• Maternal smoker• Partner smokes• 2+ units of alcohol• Bottle feeding• Bed sharing

Risk >100/1000, i.e. 10%

The role of alcohol in New Zealand

• Review of all infant deaths referred to the coroner in the Auckland region, 2000-2009

• Reviewed police records• Total of 188 sudden unexpected deaths in infancy (SUDI)• 121 occurred while bed sharing = 64%• Alcohol was implicated in 17 = 14% of bed sharing deaths

Hutchison et al, Acta Paediatrica, 2011

Could maternal obesity (+/- sagging mattress) increase the risk?

Conclusions 1: Bed sharing and SIDS

• There is no risk from bed sharing if the mother stays awake.

• Bed sharing infants placed back in their cot are not at increased risk of SIDS.

• The risk of SIDS with bed sharing is high when the mother smokes or smoked in pregnancy.

• Maternal alcohol increases the risk.• Maternal obesity increases the risk.• There is a small increased risk when the mother does not

smoke in infants <3 months of age.

Conclusions 2: Bed sharing and SIDS

• Bed sharing is associated with a longer duration of breastfeeding, but the effect is small

• There is no evidence that bed sharing is protective against SIDS in any group

• The only group shown NOT to be at increased risk is infants 3+ months of age, not preterm or low birthweight, with non-smoking parents and no parental alcohol or recreational drugs use and not sleeping on a sofa

Why is this issue important

• Although SIDS has dropped dramatically, SUDI continues to be the major cause of death in the postneonatal age group. For most countries the SUDI rate is around 0.5/1000 live births (SIDS 0.25/1000), but 1.1/1000 in NZ

• 50-70% of SUDIs are occurring in a bed sharing environment, and this reaches 90+% in the first month of life. (In a 10 year review in Auckland 64% were bed sharing and this was 92% in those less than one month of age.)

What might be done?

1. Parents have the right to know

2. Modelling appropriate infant care practices in obstetric units is vital.

3. CYMRC is emphasising that the mechanism is likely to be due to suffocation. Suffocation is clearly preventable.

4. CYMRC is supporting the use of wahakura and pepi-pods.

5. Community advertising should be considered.

Definition of Sudden Unexpected Death in Infancy

• Not an ICD code

• Seen through the eyes of the caregiver• Under 1 year• Excludes major external force e.g. motor vehicle• Unexpected Death usually in Sleep• Death without caregivers being alerted to a problem

Includes

Suffocation in bed, wedged, face covered, overlain

Unrecognised illness, e.g. infectious, metabolic, cardiac

SIDS (no cause after complete assessment)

Unascertained

Sudden Unexpected Death in Infancy

• 60-70 SUDI per year• Many preventable• A public health emergency?!

• Good news 3,000 babies have not died since 1992• Disappeared off nation’s radar?

• “Among the industrialized nations, New Zealand has the highest rate 1.1/1000” • Maori 2.3, Pacific 1.3, Other 0.5 (per 1000 live births)

SUDI and bed sharing, 2003-2007

Number of deaths = 359

Bed sharing status unknown = 101

Bed sharing 154 (60%)

Not bed sharing 104 (40%)

Why do infants sleep in unsafe places?

• lack of awareness• infant unsettled

o moved to unsafe space

• no safe arrangement availableo no cot, too cold, over crowded

• make shift arrangementso social gathering, away from home, decorating

• parental intoxication

Suffocation or Strangulation in Bed

• Entrapment/wedgingo Soft surfaces, bedding poor fitting, bed/wallo Broken cotso Sofa, pillows and cushionso Domestic chaos

• Overlayingo Adult > sibling > mother while feeding

• Infants 20 times more likely to suffocate in adult bed than in a cot or bassinette

• Hazards away from home and make shift

Own Sleep Space

• Risk from bed sharing increased by• Smoke exposure• Infant preterm or low birth weight• Under 3 months old• If others in the sleep space difficult to rouse e.g. alcohol, drugs,

medicines, toddlers.• Sofa sleeping

• Parents have a right to know risks of bed sharing• Own sleep space essential if others risks cluster

The CYMRC recommends that the Commission should:

 

Support DHBs in developing quality improvement systems that promote evidence-based safe sleeping practices for infants, which are modelled in every DHB and supported by clear policy and audit systems.

A network across DHBs should provide clear national guidance, reduce duplication and minimise variation, while also supporting local participation in training and development of safe sleep practices.

Needs Assessment

• Starts before birth • Highlights where extra support needed• Environmental risks• Infant factors

• Plan documents how needs will be met• Parents fully informed as of right• Make good choices easy

Support Families

• Systems to get a space for baby to sleep• Heating to ensure warm• Reduce overcrowding• Wahakura • Pepi Pod• Cot rental system?

• Anticipatory guidance to plan for night time waking management and feeds

• Modeling safe sleep in hospital

Pepi Pod

Wahakura

Risk Communication

• Low correlation between a risk’s • “hazard” (how much harm it’s likely to do) and its• “outrage” (how upset it’s likely to make people)

• Disempowering• SIDS – unexplained can happen to anyone

• Empowering• Suffocation and Strangulation – preventable

New focus of Suffocation and Strangulation

FINAL CONCLUSIONS

• The MoH recommendations on Safe Sleep are evidence based.

• SIDS or SUDI are preventable• Application of what we currently know could eliminate

SIDS (reduce it to 5-6 deaths per annum)• The challenge is to find ways of implementing our

knowledge, especially finding ways to safely bed share.

Pacifiers and risk of SIDS Mitchell, Blair, L’Hoir. Pediatrics 2006

Mitchell 1987-90 New Zealand 0.43

Fleming 1993-95 UK 0.41

L’Hoir 1995-96 Netherlands 0.19

Hauck 1993-96 USA 0.33

Brooke 1996-99 Scotland 0.33

McGarvey 1994-98 Ireland 0.10

Carpenter 1992-96 Europe 0.44

Vennemann 1998-2001 Germany 0.39

The AAP task force recommends use of a pacifier throughout the first year of life according to the following procedures:• The pacifier should be used when placing the infant

down for sleep and not be reinserted once the infant falls asleep. If the infant refuses the pacifier, he or she should not be forced to take it.

• Pacifiers should not be coated in any sweet solution.• Pacifiers should be cleaned often and replaced

regularly. • For breastfed infants, delay pacifier introduction until

1 month of age to ensure that breastfeeding is firmly established.

Other possible health effects of pacifier

Disadvantages• Increased otitis media• Increased dental malocclusion• Decrease in duration of breastfeeding

Advantages• Decrease in dental malocclusion from finger

sucking• Reduction in GE reflux• Reduction in behavioural distress

Possible mechanisms

• Reduction in infant face down• Reduction in GE reflux• Increased arousal• Improved airway

Recommendations

• The evidence is consistent and moderately strong.• The possible detrimental effects have to be balanced

against the low risk of SIDS.• Some countries are now recommending pacifier use, at

least in bottle fed infants.• Pacifiers should no longer be discouraged, but not

specifically encouraged.

Head covering

10 studies with control data

Prevalence in SIDS was 24.6% vs. 3.2% in controls

Pooled unadjusted OR = 9.6 (95% CI = 7.9-11.7)

Pooled adjusted OR = 16.9 (95% CI = 12.6-22.7)

Population attributable risk = 27.1%

Blair et al, Arch Dis Child 2008

Copyright ©2008 BMJ Publishing Group Ltd.

Blair, P S et al. Arch Dis Child 2008;93:778-783

Figure 1 Forest plot of unadjusted odds ratio (and 95% CI) for infants found with head covered by bedclothes after last sleep.

Recommendation

• In UK the “Feet to foot” campaign advised parents to place the feet of the infant at the foot of the cot to prevent head covering (1997).

• This advice was endorsed by the American Academy of Pediatrics (2000).

• Although intuitively sensible there is no evidence that it reduces risk of head covering or lowers risk of SIDS.

Sleeping sack

In The Netherlands the use of the infant sleeping sack is common.

L’Hoir et al showed in 1998 (Eur J Pediatr) that the sleeping sack was associated with a lower risk of SIDS

Its use might prevent (1) head covering, (2) turning to the prone sleeping position, and (3) thermal stress

Case Control OR

No 63% 25% 1.0

Yes 37% 75% 0.3

Immunizations• The anti-immunisation lobby have postulated that

immunisations cause SIDS.

• However, immunizations are associated with a reduced risk of SIDS (possibly because children that are being immunized are well). Pooled OR=0.59 (0.53-0.66)