An 8 year study of risk factors for SIDS: bed-sharing versus non-bed-sharing

Death from Failed Protection? An Evolutionary-Developmental Theory of Sudden Infant Death Syndrome

Sudden infant death syndrome (SIDS) has been mainly described from a risk perspective, with a focus on endogenous, exogenous, and temporal risk factors that can interact to facilitate lethal outcomes. Here we discuss the limitations that this risk-based paradigm may have, using two of the major risk factors for SIDS, prone sleep position and bed-sharing, as examples. Based on a multipronged theoretical model encompassing evolutionary theory, developmental biology, and cultural mismatch theory, we conceptualize the vulnerability to SIDS as an imbalance between current physiologic-regulatory demands and current protective abilities on the part of the infant. From this understanding, SIDS appears as a developmental condition in which competencies relevant to self-protection fail to develop appropriately in the future victims. Since all of the protective resources in question are bound to emerge during normal infant development, we contend that SIDS may reflect an evolutionary mismatch situation-a constellation in which certain modern developmental influences may overextend the child's adaptive (evolutionary) repertoire. We thus argue that SIDS may be better understood if the focus on risk factors is complemented by a deeper appreciation of the protective resources that human infants acquire during their normal development. We extensively analyze this evolutionary-developmental theory against the body of epidemiological and experimental evidence in SIDS research and thereby also address the as-of-yet unresolved question of why breastfeeding may be protective against SIDS.

Evidence Base for 2022 Updated Recommendations for a Safe Infant Sleeping Environment to Reduce the Risk of Sleep-Related Infant Deaths

Every year in the United States, approximately 3500 infants die of sleep-related infant deaths, including sudden infant death syndrome (SIDS) (International Statistical Classification of Diseases and Related Health Problems 10th Revision [ICD-10] R95), ill-defined deaths (ICD-10 R99), and accidental suffocation and strangulation in bed (ICD-10 W75). After a substantial decline in sleep-related deaths in the 1990s, the overall death rate attributable to sleep-related infant deaths have remained stagnant since 2000, and disparities persist. The triple risk model proposes that SIDS occurs when an infant with intrinsic vulnerability (often manifested by impaired arousal, cardiorespiratory, and/or autonomic responses) undergoes an exogenous trigger event (eg, exposure to an unsafe sleeping environment) during a critical developmental period. The American Academy of Pediatrics recommends a safe sleep environment to reduce the risk of all sleep-related deaths. This includes supine positioning; use of a firm, noninclined sleep surface; room sharing without bed sharing; and avoidance of soft bedding and overheating. Additional recommendations for SIDS risk reduction include human milk feeding; avoidance of exposure to nicotine, alcohol, marijuana, opioids, and illicit drugs; routine immunization; and use of a pacifier. New recommendations are presented regarding noninclined sleep surfaces, short-term emergency sleep locations, use of cardboard boxes as a sleep location, bed sharing, substance use, home cardiorespiratory monitors, and tummy time. In addition, additional information to assist parents, physicians, and nonphysician clinicians in assessing the risk of specific bed-sharing situations is included. The recommendations and strength of evidence for each recommendation are published in the accompanying policy statement, which is included in this issue.

Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment

Each year in the United States, ∼3500 infants die of sleep-related infant deaths, including sudden infant death syndrome (SIDS) (International Classification of Diseases, 10th Revision [ICD-10] R95), ill-defined deaths (ICD-10 R99), and accidental suffocation and strangulation in bed (ICD-10 W75). After a substantial decline in sleep-related deaths in the 1990s, the overall death rate attributable to sleep-related infant deaths has remained stagnant since 2000, and disparities persist. The triple risk model proposes that SIDS occurs when an infant with intrinsic vulnerability (often manifested by impaired arousal, cardiorespiratory, and/or autonomic responses) undergoes an exogenous trigger event (eg, exposure to an unsafe sleeping environment) during a critical developmental period. The American Academy of Pediatrics recommends a safe sleep environment to reduce the risk of all sleep-related deaths. This includes supine positioning; use of a firm, noninclined sleep surface; room sharing without bed sharing; and avoidance of soft bedding and overheating. Additional recommendations for SIDS risk reduction include human milk feeding; avoidance of exposure to nicotine, alcohol, marijuana, opioids, and illicit drugs; routine immunization; and use of a pacifier. New recommendations are presented regarding noninclined sleep surfaces, short-term emergency sleep locations, use of cardboard boxes as a sleep location, bed sharing, substance use, home cardiorespiratory monitors, and tummy time. Additional information to assist parents, physicians, and nonphysician clinicians in assessing the risk of specific bed-sharing situations is also included. The recommendations and strength of evidence for each recommendation are included in this policy statement. The rationale for these recommendations is discussed in detail in the accompanying technical report.

Maternal intentions towards infant sleeping practices in Ireland

AIM

Mortality from Sudden Infant Death Syndrome (SIDS) has reduced by 50%-85% globally. Despite improvements from 1990 to 2009, the Irish SIDS rate has plateaued. Reasons for this are unclear, but may be related to a reduced parental SIDS awareness. Our study aimed to assess intentions regarding infant sleeping practices in mothers in Ireland.

METHODS

A cross-sectional survey of post-partum mothers was performed in the Rotunda Hospital over a four month period. Mothers with a history of SIDS, miscarriage or neonatal admissions were excluded.

RESULTS

Of 451 participants, unsafe sleeping positions were intended by 15.4%, reduced by Irish ethnicity [AOR = 0.52, 95% CI = 0.277-0.959, P = .036]. Safe sleep locations were intended by 66%, increased by Irish ethnicity [AOR = 2.6, 95% CI = 1.617-4.191, P < .001], and reduced by young maternal age [AOR = 0.15, 95% CI = 0.03-0.713, P = .02]. Maternal smoking was more likely in mothers with lower educational level [AOR = 3.51, 95% CI = 1.169-10.56, P = .03]. Soft bedding use was intended by 34.8%, increased in younger mothers [AOR = 2.28, 95% CI = 1.04-4.98, P = .04]. Breastfeeding was intended by 72.2%, decreased by Irish ethnicity [AOR = 0.14, 95% CI = 0.067-0.271, P < .001], and low maternal education [AOR = 0.22, 95% CI = 0.117-0.406, P < .001].

CONCLUSION

Educational campaigns on safe sleep for infants in Ireland need to address modifiable SIDS risks factors, focusing on younger, non-Irish mothers, with lower educational attainment.

Global trends in the extent of death scene investigation performed for sudden and unexpected death of infant (SUDI) cases: A systematic review

Sudden unexpected death of infants (SUDI) is the rapid and unexpected death of an infant aged less than 1year old. These deaths are referred for a medico-legal investigation to establish cause of death. National and regional protocols for the investigation of SUDI cases have been established in some countries and these typically include a death scene investigation component. However, there is a paucity of literature detailing the nature and extent of death scene investigation protocols. A systematic review was conducted to review the scope of death scene investigation of SUDI cases worldwide. Relevant articles (n=74) were identified by searching four literature databases, three discipline-specific journals, as well as each article's reference list, until saturation was reached. Of the 16 countries represented by the included articles, seven made specific reference to the standardised protocol used, which included photography, interviews and/or scene re-enactments. The remaining 54 studies appeared to include a subset of these analyses during death scene investigation, which varied between countries, and between SUDI admissions. This may be attributed to the differing socio-economic standings of countries, and the resources available. Only four studies were from developing countries, three of which originated from South Africa. Overall, where a standardised death scene investigation was performed, it added value to the post-mortem investigation; as such, death scene investigation should be encouraged in SUDI investigation. To this end, protocols should be established nationally, and contain core analyses, which could be expanded depending on the needs and resources of the country.

Health Messaging and African-American Infant Sleep Location: A Randomized Controlled Trial

Infant-parent bedsharing increases the risk of SIDS and other sleep-related deaths. Despite AAP recommendations to avoid bedsharing, public health efforts have been unsuccessful in changing behaviors. African-American infants are more than twice as likely to die from SIDS and other sleep-related deaths, and are also twice as likely to bedshare with their parents. Further, African-American parents have a high degree of self-efficacy with regards to preventing infant suffocation, but low self-efficacy with regards to SIDS risk reduction. It is unclear whether messages emphasizing suffocation prevention will decrease bedsharing. To evaluate the impact of specific health messages on African-American parental decisions regarding infant sleep location. We conducted a randomized, controlled trial of African-American mothers of infants. The control group received standard messaging emphasizing AAP-recommended safe sleep practices, including avoidance of bedsharing, for the purposes of SIDS risk reduction. The intervention group received enhanced messaging emphasizing safe sleep practices, including avoidance of bedsharing, for both SIDS risk reduction and suffocation prevention. Participants completed interviews at 2-3 weeks, 2-3 months, and 5-6 months after the infant's birth. 1194 mothers were enrolled in the study, and 637 completed all interviews. Bedsharing, both usually (aOR 1.005 [95 % CI 1.003, 1.006]) and last night (aOR 1.004 [95 % CI 1.002, 1.007]) increased slightly but statistically significantly with infant age (p < 0.001). Receipt of the enhanced message did not impact on sleep location. Maternal belief that bedsharing increased the risk of SIDS or suffocation declined over 6 months (p < 0.001) and did not differ by group assignment. African-American mothers who received an enhanced message about SIDS risk reduction and suffocation prevention were no less likely to bedshare with their infants.

CLINICAL TRIALS REGISTRATION

Clinical Trials.gov identifier NCT01361880.

Parent-infant co-sleeping and the implications for sudden infant death syndrome

In 2015 the National Institute for Health and Care Excellence (NICE) updated its 2006 guideline to clarify the association between parent infant co-sleeping and sudden infant death syndrome (SIDS). The practice of co-sleeping is a topic of continuing controversy and debate. Rather than highlighting the risks, the emphasis of the NICE guideline is to provide parents with balanced information so that they can make informed decisions about where their babies sleep. This contradicts previous public health messages on co-sleeping that discourages parents from the practice. Consequently, the updated national guideline has been criticised for failing to provide parents with safer sleep information, which has led to widespread confusion for parents and professionals. Health professionals can deliver safer sleep advice to support parents in their decision-making. However, as a result of inconsistent guidelines and evidence about parent-infant co-sleeping, health professionals may feel apprehensive and ill-equipped to provide advice and support. This article draws on a non-exhaustive literature review to discuss the risks and benefits of parent-infant co-sleeping, and the implications of this practice for SIDS. It also aims to provide transparency and improve understanding for health professionals so that they can support parents to adopt safer sleep strategies for their baby.

Sleep-Related Infant Deaths in Victoria: A Retrospective Case Series Study

BACKGROUND

There is general agreement that in some circumstances, sharing a sleep surface of any kind with an infant increases the risk of sudden unexpected death in infancy. There is a paucity of research conducted in Australia examining this issue. This study examines the frequency and distribution of sleep-related infant deaths in a defined population, and reports the proportion that occurred in the context of bed-sharing.

METHODS

A retrospective population-based case series study was conducted of infants (≤365 days) who died in a sleeping context during the period 1 January 2008 to 31 December 2010 in the state of Victoria, Australia. Information about the infant, caregiver, sleeping environment and bed-sharing was collected from a review of the coroner's death investigation record.

RESULTS

During the 3-year study period, 72 infant deaths occurred in a sleeping context. Of these, 33 (45.8 %) occurred in the context of bed-sharing: n = 7 in 2008; n = 11 in 2009; and n = 15 in 2010. Further analysis of the 33 deaths occurring in the context of bed-sharing showed that in this group, bed-sharing was largely intentional, habitual and most often involved the mother as one of the parties.

CONCLUSIONS

Given the case series nature of the study design, a causal relationship between bed-sharing and infant death could not be inferred. However the fact that nearly half of all sleep-related deaths occurred in the context of bed-sharing, provides strong support for the need to undertake definitive analytic studies in Australia so that evidence-based advice can be provided to families regarding the safety of bed-sharing practices.

SIDS and Other Sleep-Related Infant Deaths: Evidence Base for 2016 Updated Recommendations for a Safe Infant Sleeping Environment

Approximately 3500 infants die annually in the United States from sleep-related infant deaths, including sudden infant death syndrome (SIDS), ill-defined deaths, and accidental suffocation and strangulation in bed. After an initial decrease in the 1990s, the overall sleep-related infant death rate has not declined in more recent years. Many of the modifiable and nonmodifiable risk factors for SIDS and other sleep-related infant deaths are strikingly similar. The American Academy of Pediatrics recommends a safe sleep environment that can reduce the risk of all sleep-related infant deaths. Recommendations for a safe sleep environment include supine positioning, use of a firm sleep surface, room-sharing without bed-sharing, and avoidance of soft bedding and overheating. Additional recommendations for SIDS risk reduction include avoidance of exposure to smoke, alcohol, and illicit drugs; breastfeeding; routine immunization; and use of a pacifier. New evidence and rationale for recommendations are presented for skin-to-skin care for newborn infants, bedside and in-bed sleepers, sleeping on couches/armchairs and in sitting devices, and use of soft bedding after 4 months of age. In addition, expanded recommendations for infant sleep location are included. The recommendations and strength of evidence for each recommendation are published in the accompanying policy statement, "SIDS and Other Sleep-Related Infant Deaths: Updated 2016 Recommendations for a Safe Infant Sleeping Environment," which is included in this issue.

Sudden unexpected death in infancy: aetiology, pathophysiology, epidemiology and prevention in 2015

Despite the fall in numbers of unexpected infant deaths that followed the 'Back to Sleep' campaigns in the early 1990 s in the UK and many other countries, such deaths remain one of the largest single groups of deaths in the postneonatal period in many Western countries. Changes in the ways in which unexpected infant deaths are categorised by pathologists and coroners, and increasing reluctance to use the term 'sudden infant death syndrome', make assessment of nationally and internationally collected data on incidence potentially inaccurate and confusing. In this paper, we review current understanding of the epidemiology and aetiology of unexpected deaths in infancy, and current hypotheses on the pathophysiology of the processes that may lead to death. We also review interventions that have been adopted, with variable degrees of effectiveness in efforts to reduce the numbers of deaths, and new approaches that offer the possibility of prevention in the future.

Bed-sharing and unexpected infant deaths: what is the relationship?

For much of human history infant survival has been largely predicated by close and continuous contact between the infant and the primary carer - almost always the mother. Many factors in post-industrial human society - notably tobacco smoking, alcohol intake and the use of recreational drugs- have been associated with increased risk to infants sleeping in close proximity to their mothers. This is particularly true for mothers who choose not to breastfeed. The question of the risks and possible benefits of bed-sharing for mothers who plan to breastfeed, do not smoke, do not drink alcohol or take recreational drugs, and are aware of how to ensure a safe infant sleep environment need to be quantified. In this paper we review the evidence from several epidemiological studies and identify the factors that make bedsharing more or less hazardous for the infant. This analysis is important in allowing us to give parents accurate and unbiased information on which to make their own choices about optimal night time care of their infants without demonising normal parental behaviour or practices.

Are baby hammocks safe for sleeping babies? A randomised controlled trial

AIM

Two reports of infants found dead after sleeping in baby hammocks have raised international concern about the safety of infant hammocks. We therefore tested whether hammock sleep affected oxygenation in infants, when they were at an age of high risk of sudden, unexpected infant death.

METHODS

Healthy, full-term 4- to 8-week-old infants were randomised to sleep either in a commercially available hammock (n = 14) or a standard bassinet (n = 9), and sleep state, oxygen desaturation (a fall in peripheral haemoglobin oxygen saturation (SpO2 ) ≥ 4%, for ≥ 4 sec from baseline to nadir), apnoea and hypopnoea, and mean SpO2 were analysed.

RESULTS

There was no significant difference in mean SpO2 (both 98.5%) or rate of oxygen desaturation events between the hammock and the bassinet cot (mean ± SD, 24 ± 20 vs. 28 ± 23 events per hour), but infants slept less in the hammock (59 ± 31 vs. 81 ± 34 min, p < 0.02).

CONCLUSION

When correctly used, the hammock sleep position did not compromise the upper airway of sleeping infants. The significance of shorter duration of sleep in the hammocks is unclear. These findings should not be applied to all baby hammocks, nor to older babies, particularly once the infant can roll. Given that it is not possible to predict when an infant will be able to roll, we strongly recommend that hammocks should not be used for unsupervised sleep.

Is "Bed Sharing" Beneficial and Safe during Infancy? A Systematic Review

Background. There is conflicting evidence regarding the safety and efficacy of bed sharing during infancy-while it has been shown to facilitate breastfeeding and provide protection against hypothermia, it has been identified as a risk factor for SIDS. Methods. A systematic search of major databases was conducted. Eligible studies were observational studies that enrolled infants in the first 4 weeks of life and followed them up for a variable period of time thereafter. Results. A total of 21 studies were included. Though the quality of evidence was low, bed sharing was found to be associated with higher breastfeeding rates at 4 weeks of age (75.5% versus 50%, OR 3.09 (95% CI 2.67 to 3.58), P = 0.043) and an increased risk of SIDS (23.3% versus 11.2%, OR 2.36 (95% CI 1.97 to 2.83), P = 0.025). Majority of the studies were from developed countries, and the effect was almost consistent across the studies. Conclusion. There is low quality evidence that bed sharing is associated with higher breast feeding rates at 4 weeks of age and an increased risk of SIDS. We need more studies that look at bed sharing, breast feeding, and hazardous circumstance that put babies at risk.

Bed sharing when parents do not smoke: is there a risk of SIDS? An individual level analysis of five major case-control studies

OBJECTIVE

To resolve uncertainty as to the risk of Sudden Infant Death Syndrome (SIDS) associated with sleeping in bed with your baby if neither parent smokes and the baby is breastfed.

DESIGN

Bed sharing was defined as sleeping with a baby in the parents' bed; room sharing as baby sleeping in the parents' room. Frequency of bed sharing during last sleep was compared between babies who died of SIDS and living control infants. Five large SIDS case-control datasets were combined. Missing data were imputed. Random effects logistic regression controlled for confounding factors.

SETTING

Home sleeping arrangements of infants in 19 studies across the UK, Europe and Australasia.

PARTICIPANTS

1472 SIDS cases, and 4679 controls. Each study effectively included all cases, by standard criteria. Controls were randomly selected normal infants of similar age, time and place.

RESULTS

In the combined dataset, 22.2% of cases and 9.6% of controls were bed sharing, adjusted OR (AOR) for all ages 2.7; 95% CI (1.4 to 5.3). Bed sharing risk decreased with increasing infant age. When neither parent smoked, and the baby was less than 3 months, breastfed and had no other risk factors, the AOR for bed sharing versus room sharing was 5.1 (2.3 to 11.4) and estimated absolute risk for these room sharing infants was very low (0.08 (0.05 to 0.14)/1000 live-births). This increased to 0.23 (0.11 to 0.43)/1000 when bed sharing. Smoking and alcohol use greatly increased bed sharing risk.

CONCLUSIONS

Bed sharing for sleep when the parents do not smoke or take alcohol or drugs increases the risk of SIDS. Risks associated with bed sharing are greatly increased when combined with parental smoking, maternal alcohol consumption and/or drug use. A substantial reduction of SIDS rates could be achieved if parents avoided bed sharing.

Sudden infant death syndrome in Korea: a retrospective analysis of autopsy-diagnosed cases

This study aimed to elucidate the demographic and sleeping environmental factors associated with sudden infant death syndrome (SIDS) in Korea. The autopsy reports of all SIDS cases reported to the National Forensic Service and Seoul National University College of Medicine between 1996 and 2008 were reviewed for data collection and analysis to identify the risk factors for SIDS. Analysis of the 355 SIDS cases reported within the study period revealed that of the 168 (47.3%) cases for which sleeping position before death had been reported, 75 (44.7%) cases had occurred after placement in prone or side position. Of the 204 (57.5%) cases for which bed-sharing situation had been reported, 121 (59.3%) deaths had occurred during bed-sharing, of which 54 (44.6%) infants were under 3 months of age, a significantly younger age than that of the non-bed-sharing cases (P = 0.0279). Analysis of the results indicated no tendency toward an increase or decrease in the use of a prone or side position. Rather, there was a statistically significant increasing trend for bed-sharing over the study period (OR, 1.087; 95% CI, 1.004-1.177; P = 0.04). These findings indicate the need for nationwide educational programs promoting a safe sleeping environment to enhance SIDS prevention.

Does cosleeping contribute to lower testosterone levels in fathers? Evidence from the Philippines

Because cross-species evidence suggests that high testosterone (T) may interfere with paternal investment, the relationships between men's transition to parenting and changes in their T are of growing interest. Studies of human males suggest that fathers who provide childcare often have lower T than uninvolved fathers, but no studies to date have evaluated how nighttime sleep proximity between fathers and their offspring may affect T. Using data collected in 2005 and 2009 from a sample of men (n = 362; age 26.0 ± 0.3 years in 2009) residing in metropolitan Cebu, Philippines, we evaluated fathers' T based on whether they slept on the same surface as their children (same surface cosleepers), slept on a different surface but in the same room (roomsharers), or slept separately from their children (solitary sleepers). A large majority (92%) of fathers in this sample reported practicing same surface cosleeping. Compared to fathers who slept solitarily, same surface cosleeping fathers had significantly lower evening (PM) T and also showed a greater diurnal decline in T from waking to evening (both p<0.05). Among men who were not fathers at baseline (2005), fathers who were cosleepers at follow-up (2009) experienced a significantly greater longitudinal decline in PM T over the 4.5-year study period (p<0.01) compared to solitary sleeping fathers. Among these same men, baseline T did not predict fathers' sleeping arrangements at follow-up (p>0.2). These results are consistent with previous findings indicating that daytime father-child interaction contributes to lower T among fathers. Our findings specifically suggest that close sleep proximity between fathers and their offspring results in greater longitudinal decreases in T as men transition to fatherhood and lower PM T overall compared to solitary sleeping fathers.

Scientific consensus forum to review the evidence underpinning the recommendations of the Australian SIDS and Kids Safe Sleeping Health Promotion Programme--October 2010

This paper summarises a 1-day scientific consensus forum that reviewed the evidence underpinning the Australian SIDS and Kids Safe Sleeping Health Promotion Programme. The focus was on each of the potentially modifiable risk factors for sudden unexpected deaths in infancy, including sudden infant death syndrome (SIDS) and fatal sleeping accidents. In particular infant sleeping position, covering of the face, exposure to cigarette smoke, room sharing, unsafe sleeping environments, bed sharing, immunisation, breastfeeding, pacifier use and Indigenous issues were discussed in depth. The participants recommended that future 'Reducing the Risk' campaign messages should focus on back to sleep, face uncovered, avoidance of cigarette smoke before and after birth, safe sleeping environment, room sharing and sleeping baby in own cot.

Autopsy findings of co-sleeping-associated sudden unexpected deaths in infancy: relationship between pathological features and asphyxial mode of death

AIM

Co-sleeping is associated with increased risk of sudden unexpected death in infancy (SUDI)/sudden infant death syndrome (SIDS). The aim of this study is to examine autopsy findings from a single U.K. specialist centre to determine the relationship between co-sleeping and cause of death.

METHODS

Retrospective analysis of >1500 paediatric autopsies carried out by paediatric pathologists over a 10-year period. SUDI was defined as sudden unexpected death of an infant aged 7-365 days; deaths were categorised into explained SUDI (cause of death was determined) and unexplained SUDI (equivalent to SIDS).

RESULTS

There were 546 SUDI; sleeping arrangements were specifically recorded in 314; of these, 174 (55%) were co-sleeping-associated deaths. Almost two thirds (59%) of unexplained SUDI were co-sleeping compared to 44% explained SUDI (95% confidence interval (CI) 1.0-27.2%, P=0.03); however, this difference remained statistically significant only for the first 5 months of life (95% CI 3.5-33.2%, P=0.01). In unexplained SUDI aged < 6 months, there were no significant differences between co-sleeping and non-co-sleeping deaths with respect to ante-mortem symptoms, intrathoracic petechiae, macroscopic lung appearances, pulmonary haemosiderin-laden macrophages, and isolation of specific bacterial pathogens; however, fresh intra-alveolar haemorrhage was reported more commonly in co-sleeping (54%) than in those that were not (38%; 95% CI 1.4-30.5%, P=0.03).

CONCLUSIONS

Co-sleeping is associated with unexplained SUDI/SIDS in infants aged < 6 months, suggesting that co-sleeping is related to the pathogenesis of death in younger infants. The finding that intra-alveolar haemorrhage is more common in co-sleeping suggests that a minority of co-sleeping-associated deaths may be related to an asphyxial process.

Risk factor changes for sudden infant death syndrome after initiation of Back-to-Sleep campaign

OBJECTIVE

To test the hypothesis that the profile of sudden infant death syndrome (SIDS) changed after the Back-to-Sleep (BTS) campaign initiation, document prevalence and patterns of multiple risks, and determine the age profile of risk factors.

METHODS

The San Diego SIDS/Sudden Unexplained Death in Childhood Research Project recorded risk factors for 568 SIDS deaths from 1991 to 2008 based upon standardized death scene investigations and autopsies. Risks were divided into intrinsic (eg, male gender) and extrinsic (eg, prone sleep).

RESULTS

Between 1991-1993 and 1996-2008, the percentage of SIDS infants found prone decreased from 84.0% to 48.5% (P < .001), bed-sharing increased from 19.2% to 37.9% (P < .001), especially among infants <2 months (29.0% vs 63.8%), prematurity rate increased from 20.0% to 29.0% (P = .05), whereas symptoms of upper respiratory tract infection decreased from 46.6% to 24.8% (P < .001). Ninety-nine percent of SIDS infants had at least 1 risk factor, 57% had at least 2 extrinsic and 1 intrinsic risk factor, and only 5% had no extrinsic risk. The average number of risks per SIDS infant did not change after initiation of the BTS campaign.

CONCLUSIONS

SIDS infants in the BTS era show more variation in risk factors. There was a consistently high prevalence of both intrinsic and especially extrinsic risks both before and during the Back-to-Sleep era. Risk reduction campaigns emphasizing the importance of avoiding multiple and simultaneous SIDS risks are essential to prevent SIDS, including among infants who may already be vulnerable.

The Black and White of infant back sleeping and infant bed sharing in Florida, 2004-2005

Not using the infant back sleep position is an established risk factor for sudden unexpected infant death (SUID). Infant bed sharing may also increase SUID risk, particularly under certain circumstances. Both of these infant sleeping behaviors are disproportionately higher among Black mothers. We explored the relationship between not using the infant back sleeping and infant bed sharing, developed separate risk factor profiles for these behaviors, and identified maternal characteristics contributing to racial differences in their practice. Merged 2004-2005 birth certificate and Pregnancy Risk Assessment Monitoring System data for 2,791 non-Hispanic Black and White Florida women were evaluated using univariable and multivariable analyses to develop risk factor profiles for infrequent back sleeping and frequent bed sharing. Cross-product interaction terms were introduced to identify factors contributing to racial differences. Infrequent back sleeping and frequent bed sharing were reported by two-thirds of Black women and one-third of White women. There was no association between the infant sleeping behaviors when adjusted for race (adjusted odds ratio [aOR], 1.04; 95% CI, 0.83-1.31). The infant sleeping behaviors shared no common independent maternal characteristics. Father acknowledgement on the birth certificate was a strong contributor to racial differences in infrequent back sleeping while breastfeeding, trimester of entry to prenatal care, and maternal depression revealed notable racial differences for bed sharing. Behavior-specific and race-specific public health messages may be an important public health strategy for reducing risky infant sleeping behaviors and decreasing SUIDs.

Bed sharing and the risk of sudden infant death syndrome: can we resolve the debate?

OBJECTIVE

To conduct a meta-analysis on the relationship between bed sharing and sudden infant death syndrome (SIDS) risk.

STUDY DESIGN

Data from PubMed and Medline were searched for studies published after Jan 1, 1970. The search strategy included articles with the terms "sudden infant death syndrome," "sudden unexpected death," and "cot death" with "bed sharing" or "co-sleeping." To further specify the potential risk of bed sharing and SIDS, subgroup analyses were performed.

RESULTS

Eleven studies met inclusion criteria and were included in the final meta-analysis. The combined OR for SIDS in all bed sharing versus non-bed sharing infants was 2.89 (95% CI, 1.99-4.18). The risk was highest for infants of smoking mothers (OR, 6.27; 95% CI, 3.94-9.99), and infants <12 weeks old (OR, 10.37; 95% CI, 4.44-24.21).

CONCLUSIONS

Bed sharing is a risk factor for SIDS and is especially enhanced in smoking parents and in very young infants.

SIDS and other sleep-related infant deaths: expansion of recommendations for a safe infant sleeping environment

Despite a major decrease in the incidence of sudden infant death syndrome (SIDS) since the American Academy of Pediatrics (AAP) released its recommendation in 1992 that infants be placed for sleep in a nonprone position, this decline has plateaued in recent years. Concurrently, other causes of sudden unexpected infant death occurring during sleep (sleep-related deaths), including suffocation, asphyxia, and entrapment, and ill-defined or unspecified causes of death have increased in incidence, particularly since the AAP published its last statement on SIDS in 2005. It has become increasingly important to address these other causes of sleep-related infant death. Many of the modifiable and nonmodifiable risk factors for SIDS and suffocation are strikingly similar. The AAP, therefore, is expanding its recommendations from being only SIDS-focused to focusing on a safe sleep environment that can reduce the risk of all sleep-related infant deaths including SIDS. The recommendations described in this report include supine positioning, use of a firm sleep surface, breastfeeding, room-sharing without bed-sharing, routine immunization, consideration of a pacifier, and avoidance of soft bedding, overheating, and exposure to tobacco smoke, alcohol, and illicit drugs. The rationale for these recommendations is discussed in detail in this technical report. The recommendations are published in the accompanying "Policy Statement--Sudden Infant Death Syndrome and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment," which is included in this issue (www.pediatrics.org/cgi/doi/10.1542/peds.2011-2220).

SIDS and other sleep-related infant deaths: expansion of recommendations for a safe infant sleeping environment

Despite a major decrease in the incidence of sudden infant death syndrome (SIDS) since the American Academy of Pediatrics (AAP) released its recommendation in 1992 that infants be placed for sleep in a nonprone position, this decline has plateaued in recent years. Concurrently, other causes of sudden unexpected infant death that occur during sleep (sleep-related deaths), including suffocation, asphyxia, and entrapment, and ill-defined or unspecified causes of death have increased in incidence, particularly since the AAP published its last statement on SIDS in 2005. It has become increasingly important to address these other causes of sleep-related infant death. Many of the modifiable and nonmodifiable risk factors for SIDS and suffocation are strikingly similar. The AAP, therefore, is expanding its recommendations from focusing only on SIDS to focusing on a safe sleep environment that can reduce the risk of all sleep-related infant deaths, including SIDS. The recommendations described in this policy statement include supine positioning, use of a firm sleep surface, breastfeeding, room-sharing without bed-sharing, routine immunizations, consideration of using a pacifier, and avoidance of soft bedding, overheating, and exposure to tobacco smoke, alcohol, and illicit drugs. The rationale for these recommendations is discussed in detail in the accompanying "Technical Report--SIDS and Other Sleep-Related Infant Deaths: Expansion of Recommendations for a Safe Infant Sleeping Environment," which is included in this issue of Pediatrics (www.pediatrics.org/cgi/content/full/128/5/e1341).

Alcohol as a risk factor for sudden infant death syndrome (SIDS)

AIM

To test whether alcohol is a risk factor for sudden infant death syndrome (SIDS).

DESIGN AND SETTING

US epidemiological study using computerized death certificates, linked birth and infant death dataset, and Fatality Analysis Reporting System.

PARTICIPANTS

All SIDS cases (n = 129,090) and other infant deaths (n = 295,151) from 1973-2006; all persons involved in late-night alcohol-related crashes (n = 135,946) from 1994-2008.

MEASUREMENTS

Three measures were used: the expected number of deaths on New Year versus the observed number (expected values were determined using a locally weighted scatterplot smoothing polynomial), the average number of weekend deaths versus the average number of weekday deaths, and the SIDS death rate for children of alcohol-consuming versus non-alcohol-consuming mothers.

FINDINGS

These measures indicate that the largest spikes in alcohol consumption and in SIDS (33%) occur on New Year, alcohol consumption and SIDS increase significantly on weekends, and children of alcohol-consuming mothers are much more likely to die from SIDS than are children of non-alcohol-consuming mothers.

CONCLUSIONS

Alcohol consumption appears to be a risk factor for sudden infant death syndrome, although it is unclear whether alcohol is an independent risk factor, a risk factor only in conjunction with other known risk factors (like co-sleeping), or a proxy for other risk factors associated with occasions when alcohol consumption increases (like smoking). Our findings suggest that caretakers and authorities should be informed that alcohol impairs parental capacity and might be a risk factor for sudden infant death syndrome; in addition, future research should further explore possible connections between sudden infant death syndrome and alcohol.

Bed-sharing among six-month-old infants in western Sweden

AIM

In spite of several reports of an increased risk of sudden infant death syndrome (SIDS) in connection with bed-sharing, it is not an uncommon practice. The aim of this study was to examine bed-sharing at 6 months of age and the factors that are associated with bed-sharing.

METHODS

Our cohort comprised 8176 randomly chosen families. At 6 month of age, the families received an invitation to the study, with a questionnaire, which was completed by 5605 families (response rate 68.5%).

RESULTS

Of the families, 19.8% bed-shared. In the multivariate analysis, we found a correlation between breast-feeding and bed-sharing (breast-feeding at 6 months: OR 1.94; 95% CI 1.56, 2.41). Moreover, we found an association with 3+ nightly awakenings at 6 months (2.70; 2.20, 3.32). It was more common to share a bed if the parent was single (2.04; 1.19, 3.51) and less common if the infant was bottle-fed in the first week (0.70; 0.54, 0.90). Never using a pacifier was associated with a higher frequency of bed-sharing.

CONCLUSION

We found a correlation between breast-feeding and bed-sharing as well as between sleeping problems and a single parent. A lower percentage of infants sleeping in the parental bed were seen in association with formula feeding in the first week after birth.

Where should my baby sleep: a qualitative study of African American infant sleep location decisions

BACKGROUND

African American infants are of higher risk for sudden infant death syndrome (SIDS) and accidental suffocation than other infants and are up to 4 times more likely to bedshare with their parents.

OBJECTIVE

To investigate, using qualitative methods, factors influencing African American parents' decisions regarding infant sleep location (room location and sleep surface).

METHODS

Eighty-three mothers participated in focus groups or individual interviews. Questions probed reasons for infant sleep location decisions and influences on decision making.

RESULTS

Most of the mothers in this study slept in the same room as their infant. Reasons for roomsharing included space, convenience, and safety. Mothers largely decided on infant sleep surface because of space for/availability of crib, comfort, convenience, and safety. Both roomsharing and bedsharing were often chosen to make feeding and checking on the infant more convenient. Mothers who chose not to bedshare cited privacy, concern that the infant would become attached to the parents' bed, and fears about suffocation. Mothers who chose to bedshare often cited the ability to maintain vigilance while asleep. Low-income mothers also used bedsharing as a defense against environmental dangers.

CONCLUSION

African American mothers in this study viewed both roomsharing and bedsharing as strategies to keep their infants safe. Efforts to encourage roomsharing without bed-sharing must address parental concerns about space for/ availability of a crib, convenience, infant and parent comfort, and infant safety.

Bed sharing among black infants and sudden infant death syndrome: interactions with other known risk factors

OBJECTIVE

Bed sharing has been associated with sudden infant death syndrome (SIDS) and may contribute to the racial disparity seen in infant mortality. It is unclear how bed sharing interacts with other factors to impact SIDS risk. We aimed to measure the effects of bed sharing on risk of SIDS in blacks and to determine whether the risk is modified by other characteristics of the sleep environment.

METHODS

Characteristics of 195 black infants who died of SIDS were compared with matched controls. The moderating influence of known SIDS risk factors on the effect of bed sharing on risk of SIDS was examined using logistic regression.

RESULTS

Almost half (47.4%) of the study population bed shared during the last/reference sleep (58% cases and 37% controls). Bed sharing was associated with 2 times greater risk of SIDS compared with not bed sharing. The deleterious effect of bed sharing was more pronounced with a soft sleep surface, pillow use, maternal smoking, and younger infant age. However, bed sharing was still associated with an increased risk of SIDS, even when the infant was not using a pillow or sleeping on a firm surface. The strongest predictors of SIDS among bed-sharing infants were soft sleep surface, nonuse of a pacifier, and maternal smoking during pregnancy.

CONCLUSIONS

Bed sharing is a common practice among black infants. It is associated with a clear and strong increased risk of SIDS, which is even greater when combined with other known risk factors for SIDS. This practice likely contributes to the excess incidence of SIDS among blacks, and culturally competent education methods must be developed to target this high-risk group.

Virological investigations in sudden unexpected deaths in infancy (SUDI)

Previous studies have implicated viral infections in the pathogenesis of sudden unexpected death in infancy (SUDI), and routine virological investigations are recommended by current SUDI autopsy protocols. The aim of this study is to determine the role of post-mortem virology in establishing a cause of death. A retrospective review of 546 SUDI autopsies was carried out as part of a larger series of >1,500 consecutive paediatric autopsies performed over a 10-year period, 1996-2005, in a single specialist centre. Virological tests were performed as part of the post-mortem examination in 490 (90%) of the 546 SUDI autopsies, comprising 4,639 individual virological tests, of which 79% were performed on lung tissue samples. Diagnostic methods included immunofluorescence assays (using a routine respiratory virus panel; 98% of cases), cell culture (61%), rapid culture techniques such as the DEAFF test for CMV (55%), PCR (13%), electron microscopy (10%), and others. Virus was identified in only 18 cases (4%), viz. five cases of enterovirus, four of RSV, three of HSV and CMV, and one each of adenovirus, influenza virus and HIV. In seven of the 18 cases the death was classified as due to viral infection, whilst of the remaining 11 cases, death was due to bacterial infection in five, a non-infective cause in one and unexplained in five. Virus was identified in 33% of deaths due to probable viral infections, but also in 6% of SUDI due to bacterial infections, and in 2% of SUDI due to known non-infective causes and unexplained SUDI. When predominantly using immunofluorescence, virus is identified in only a small proportion of SUDI autopsies, resulting in a contribution to the final cause of death in <2% of SUDI post-mortem examinations. Routine post-mortem virological analysis by means of an immunofluorescence respiratory virus panel appears to be of limited benefit in SUDI for the purposes of determining cause of death. Application of a broader panel using more sensitive detection techniques may reveal more viruses, although their contribution to the final cause of death requires further exploration.

Sleep and sleep ecology in the first 3 years: a web-based study

This study was designed to provide data on sleep patterns during the first 3 years, based on a large US-Canada Internet sample, to assess the prevalence of parental interventions and related factors of infant sleep ecology and to evaluate the links between sleep ecology and sleep. Five thousand six parents completed a web-based online questionnaire about their children, aged from birth to 36 months. The questionnaire included items pertaining to sleep patterns, sleep environment, sleep-related parental interventions, sleep position, and demographic information. The results reflected clear sleep-related developmental changes including a decrease in daytime sleep and total sleep time, as well as consolidation of sleep during the night, which was manifested in a decrease in night wakings and nocturnal wakefulness. Sleep ecology and parental behaviors significantly explained a portion of the variance in the child's sleep patterns. Parental interventions that encourage independence and self-soothing were associated with extended and more consolidated sleep, especially in comparison to more active interactions that were associated with shorter and more fragmented sleep. These findings provide parents and professionals reference data for assessing sleep in young children. Furthermore, the results provide information on specific ecological factors that are associated with increased risk for sleep problems.

Infant sleep location: associated maternal and infant characteristics with sudden infant death syndrome prevention recommendations

OBJECTIVE

To identify factors associated with infant sleep location.

STUDY DESIGN

Demographic information and infant care practices were assessed for 708 mothers of infants ages 0 to 8 months at Women, Infants and Children centers. Generalized linear latent mixed models were constructed for the outcome, sleeping arrangement last night (room-sharing without bed-sharing versus bed-sharing, and room-sharing without bed-sharing versus sleeping in separate rooms).

RESULTS

Two-thirds of the mothers were African-American. A total of 48.6% mothers room-shared without bed-sharing, 32.5% bed-shared, and 18.9% slept in separate rooms. Compared with infants who slept in separate rooms, infants who room-shared without bed-sharing were more likely to be Hispanic (odds ratio [OR], 2.58, 95% CI 1.11-5.98) and younger (3.66- and 1.74-times more likely for infants 0-1 month old and 2-3 months old, respectively, as compared with older infants). Compared with infants who bed-shared, infants who room-shared without bed-sharing were more likely to be 0 to 1 month old (OR, 1.57; 95% CI, 1.05-2.35) and less likely to be African-American (OR, 0.43; 95% CI, 0.26-0.70) or have a teenage mother (OR, 0.37; 95% CI, 0.23-0.58).

CONCLUSIONS

Approximately one-third of mothers and infants bed-share, despite increased risk of sudden infant death syndrome (SIDS). The factors associated with bed-sharing are also associated with SIDS, likely rendering infants with these characteristics at high risk for SIDS.

Sudden infant death syndrome: another year of new hope but no cure

PURPOSE OF REVIEW

Sudden infant death syndrome has inspired increasingly sophisticated studies at a time when rates are declining because of the Back-to-Sleep campaign, but ethnic disparities are widening. This review evaluates and discusses original, recent research in this area.

RECENT FINDINGS

The epidemiology of sudden infant death syndrome was evaluated, corroborating known risk factors and identifying new risk factors such as socioeconomic depression and air pollution. Deficits in our understanding of risk factors for this syndrome persist, suggesting a need for ethnicity-specific education, especially among the underserved. Both autopsy and genetic testing were found to improve diagnostic accuracy or identify other causes of death (e.g. long Q-T syndrome). Debate persists over counseling regarding pacifiers and co-sleeping within the context of breastfeeding. Support was found for a relationship between sudden infant death syndrome and autonomic dysregulation via the serotonergic pathway, but more research is needed.

SUMMARY

The cause of sudden infant death syndrome remains elusive. Recent studies, however, suggest that improved culturally sensitive educational programs, increased diagnostic specificity, and further clarification of the link between genetics and developmental stage might further decrease the number of infants lost to this devastating disease and elucidate the mechanism(s) responsible for this syndrome.

Bed-sharing in the first four months of life: a risk factor for sudden infant death

AIM

To investigate the risk of sudden infant death in the Netherlands during bed-sharing in the first half year of life and the protective effect of breastfeeding on it.

METHODS

During a 10-year period between September 1996 and September 2006 nationwide, 213 cot deaths were investigated.

RESULTS AND DISCUSSION

Of 138 cot deaths of less than 6 months of age, 36 (26%) bed-shared. In a reference group of 1628 babies from infant welfare centres only 9.4% were bed-sharing in the night prior to the interview. After correction for smoking of one or both parents the odds ratio for cot death during bed-sharing with parents decreased with age from 9.1 (CI 4.2-19.4) at 1 month, to 4.0 (CI 2.3-6.7) at 2 months, to 1.7 (CI 0.9-3.4) at 3 months and to 1.3 (CI 1.0-1.6) at 4 through 5 months of age. The excess risk (OR > 1) associated with bed-sharing is itself not significantly influenced by the presence or absence of breastfeeding.

CONCLUSION

Bed-sharing is a serious risk factor for sudden infant death for all babies of less than 4 months of age. From 4 months onwards bed-sharing did not contribute significantly to the risk of cot death anymore in our study.

Are children just small adults? The differences between paediatric and adult sleep medicine

Several important physiological and maturational changes occur in sleep development during the paediatric age range, particularly during infancy and in early childhood. As the pathology of sleep apnoea is superimposed onto a developing and often plastic physiological system, children often show a different pathophysiology to their adult counterparts. These factors need to be incorporated into the evaluation of a child's sleep problems. Particular attention should be paid to the developmental stage of the child. Investigation, interpretation and subsequent management provide further unique challenges and during successive reviews predicted normal changes must also be taken into account. This review article discusses the important physiological and maturational changes that occur in sleep during childhood, some common paediatric sleep conditions and their presentation and the appropriate evaluation and management of these conditions. In the course of the discussion, we have stressed important differences between paediatric and adult sleep medicine.

Identifying infants at risk for sudden infant death syndrome

PURPOSE OF REVIEW

This review examines recent research relevant to the underlying pathophysiology and risk factors for sudden infant death syndrome.

RECENT FINDINGS

Current research focuses on the linkage between known risk factors and vulnerability, genetic contributions, and the role of dysfunctional brainstem neurotransmission in the pathogenesis of this syndrome. While social inequalities, prematurity, maternal smoking, infant sleeping practices and sleep environment, arousal failures and environmental pollutants remain important risk factors, new evidence is emerging that certain genetic polymorphisms may contribute to vulnerability. New neuropathological studies have provided strong support for abnormal brainstem serotonergic function. Since serotonin influences a wide range of physiological systems including breathing, the cardiovascular system, temperature, and sleep-wake cycles, this finding strongly supports the hypothesis that sudden infant death syndrome is the result of dysregulation of the autonomic nervous system and provides biological plausibility for certain risk reduction strategies.

SUMMARY

Despite a putative diagnostic shift, sudden infant death syndrome remains the most common cause of death from 1 month to 1 year of age. Recent studies confirmed established risk factors and have suggested new genetic vulnerabilities. Finally, new evidence supports a key role for abnormalities in brainstem serotonin systems in the pathophysiology of this syndrome.

Sleep arrangements and behavior of bed-sharing families in the home setting

OBJECTIVES

We aimed to provide a quantitative analysis of the sleep arrangements and behaviors of bed-sharing families to further understand the risks and benefits as well as the effects of infant age and room temperature on bed-sharing behaviors.

METHODS

Forty infants who regularly bed shared with > or = 1 parent > or = 5 hours per night were recruited. Overnight video of the family and physiological monitoring of the infant was conducted in infants' homes. Infant sleep position, potential for exposure to expired air, head covering and uncovering, breastfeeding, movements, family sleep arrangements, responses to the infant, and interactions were logged.

RESULTS

All infants slept with their mother. Fathers were included in 18 studies and siblings in 4. Infants usually slept beside the mother, separated from the father/siblings (if present), facing the mother, with head at mothers' breast level, touching, or with mother cradling. Median overnight breastfeeding duration was 40.5 minutes. Mothers commonly faced their infant, but infants were rarely in a position that potentially exposed them to maternal expired air. Fathers were seldom in contact with the infant during sleep. Of the 102 head-covering episodes observed in 22 infants, 80% were because of changes in adult sleep position. Sixty-eight percent of head uncovering was facilitated by the mother; half of these events were prompted by the infant. A 1 degree C increase in room temperature decreased infant head covering by 0.2 hours.

CONCLUSIONS

The mother-infant relationship is of prime importance during bed sharing, whether the father is present or not. The focus around breastfeeding often dictates the sleep position of the infant and mother, though room temperature may also influence this. In colder rooms infants tend to spend more time with their face covered by bedding. Frequent maternal interactions rely on the ability of the mother to arouse with little stimulation. Mothers, perhaps impaired by alcohol, smoking, or overtiredness, may not be able to respond appropriately.

Modifiable risk factors, sleep environment, developmental physiology and common polymorphisms: understanding and preventing sudden infant deaths

Unexpected death in infancy may be a consequence of recognisable pathophysiological processes, or may remain unexplained after thorough investigation. We review the appropriate investigations that should be performed after unexpected infant deaths, and the recent changes to UK law that will make such investigations mandatory from 2008. Current knowledge of the epidemiology and pathophysiology of unexpected infant deaths, together with knowledge of infant developmental physiology leads to an emphasis on the importance of a range of potential gene-environment interactions occurring in vulnerable infants at vulnerable stages of their development.

New knowledge, new insights, and new recommendations

Scientific controversy and media hype in unexpected infant deaths