Risk Factors for Suffocation and Unexplained Causes of Infant Deaths

Sleep-Related Sudden Unexpected Infant Death Among Infants Prenatally Substance Exposed

BACKGROUND AND OBJECTIVES

Maternal substance use during pregnancy heightens risk of sudden unexpected infant death (SUID), including through unsafe sleep practices. Families impacted by substance use frequently experience disproportionate social drivers of poor health and family vulnerability likely contributory to fatality risk. Characteristics of sleep-related SUID among infants born prenatally substance exposed versus nonexposed were compared to identify targeted prevention opportunities.

METHODS

Using the Sudden Death in the Young Registry, we examined SUID with sleep-related death between 2015 and 2020 across infants prenatally exposed versus nonexposed. Distribution of sleep environment characteristics, social drivers of poor health, and family vulnerability factors were examined using descriptive statistics and χ2.

RESULTS

Of 2010 infants who experienced sleep-related deaths, 283 (14%) were prenatally exposed. More than half of deaths involved an adult bed (52%, n = 1045) or surface sharing with an adult (53%, n = 1074). Supervisors of prenatally exposed infants were disproportionately impaired at infant death versus nonexposed (34%, n = 97 vs 16%, n = 279). Statistically significant associations between prenatal exposure history and vulnerability factors (insurance, child welfare involvement, intimate partner violence, health care barriers) were identified (P < .05).

CONCLUSIONS

Sleep-related SUID across infants prenatally exposed versus nonexposed differ in sleep environment characteristics and contributory social vulnerability. Disproportionate sleep environment hazards (surface sharing, supervisor impairment) are identified among prenatally exposed infants that should compel targeted prevention efforts, including safe sleep messaging, discouraging surface sharing, and engaging support persons during impairment periods. Addressing social needs and family vulnerability are also paramount to increase access to health care, safe sleep education, and material resource provision.

National Fatality Review Case Reporting System: Twenty Years of Data Collection

The National Fatality Review Case Reporting System (NFR-CRS) is a web-based data collection tool for child death review and fetal and infant mortality review teams. The NFR-CRS captures information from the multidisciplinary review, including the social and community risk factors that may have impacted the death. The NFR-CRS is a nimble data system that has evolved throughout the past 20 years. The most recent enhancements include a life stressors section focused on collecting contextual information such as racism and poverty, revised cause of death sections to better align data collected with risk factors identified in the research, and enhanced data visualizations. The NFR-CRS has improved data quality since the launch of a data quality initiative in 2015. As a result of the data quality initiative, the completeness, consistency, accuracy, and timeliness of the NFR-CRS data have improved. Limitations for the NFR-CRS include the fact that data entered are not population-based, data fields have evolved over time, and there are high percentages of missing and unknown data. Despite its limitations, the NFR-CRS remains a valuable research tool, especially when paired with other data sources.

Using Sudden Unexpected Infant Death-Case Registry Data to Drive Prevention

Sudden unexpected infant death (SUID) is a major contributor to infant death and a persistent public health issue. After an initial decline after the 1994 "Back to Sleep" campaign, SUID numbers plateaued. Currently, ∼10 infants die suddenly and unexpectedly each day in the United States. In 2019, we established a surveillance system for SUID in Cook County, Illinois, partnering our academic medical center, the Cook County Medical Examiner's Office, and child death review to create the Cook County SUID Case Registry. Our data show that, in Cook County, including the city of Chicago, ∼1 infant dies unexpectedly during sleep every week. Of these SUID, ∼25% were because of suffocation/possible suffocation. SUID peaks at 30 to 60 days old. SUID rates are 15 times higher in non-Hispanic Black infants and 3 times higher in Hispanic infants, compared with white infants. Nearly all involved 1 or more unsafe sleep factors. SUID are concentrated in community areas experiencing high hardship. Through our Community Partnership Approaches for Safe Sleep-Chicago team, we have developed collaborative prevention approaches in affected communities, allowing for conversations with families and those who support them to better understand barriers to safe sleep that they experience. These partnerships and our data allow for tailoring of informed prevention approaches to address upstream factors driving disproportionate infant mortality in historically disinvested communities, as well as optimizing the immediate risks posed by the infant sleep environment. Data from our system show the number of SUID declining modestly since our prevention work began.

Community partnership approaches to safe sleep (CPASS) program evaluation

BACKGROUND

Sudden unexpected infant death (SUID) continues to be a leading cause of death in infants in the United States (US), with significant disparities by race and socio-economic status. Infant safe sleep behaviors are associated with decreasing SUID risk, but challenges remain for families to practice these routinely. The objective of this program was to implement and evaluate a novel approach for an infant safe sleep pilot program built upon partnerships between hospitals and community-based organizations (CBOs) serving pregnant and parenting families in at-risk communities.

METHODS

Community Partnership Approaches to Safe Sleep (CPASS) was a prospectively implemented infant safe sleep program. CPASS included children's hospitals partnered with CBOs across five US cities: Portland, OR, Little Rock AR, Chicago, IL, Birmingham, AL, and Rochester, NY. The program consisted of (1) monthly learning community calls; (2) distribution of Safe Sleep Survival Kits; and (3) surveys of sites and families regarding program outcomes. Survey measures included (1) site participation in CPASS activities; (2) recipients' use of Safe Sleep Kits; and (3) recipients' safe sleep knowledge and behaviors.

RESULTS

CPASS learning community activities were consistently attended by at least two representatives (1 hospital-based, 1 CBO-based) from each site. Across the five sites, 1002 safe kits were distributed over 9 months, the majority (> 85%) to families with infants ≤ 1 month old. Among participating families, 45% reported no safe sleep location before receipt of the kit. Family adherence to nighttime safe sleep recommendations included: (1) no bedsharing (M 6.0, SD 1.8, range 0-7); (2) sleep on back (M 6.3, SD 1.7, range 0-7); and (3) sleep in a crib with no blankets/toys (M 6.0, SD 2.0, range 0-7). Site interviews described how participation in CPASS influenced safe sleep conversations and incorporated local data into counseling. Hospital-CBO relationships were strengthened with program participation.

CONCLUSIONS

The CPASS pilot program provides a new, innovative model built on hospital-community partnerships for infant safe sleep promotion in SUID-impacted communities. CPASS reached families before their infant's peak age risk for SUID and empowered families with knowledge and resources to practice infant safe sleep. Important lessons learned included improved ways to center and communicate with families.

Maternal Obesity and Risk of Sudden Unexpected Infant Death

Importance

Rates of maternal obesity are increasing in the US. Although obesity is a well-documented risk factor for numerous poor pregnancy outcomes, it is not currently a recognized risk factor for sudden unexpected infant death (SUID).

Objective

To determine whether maternal obesity is a risk factor for SUID and the proportion of SUID cases attributable to maternal obesity.

Design, Setting, and Participants

This was a US nationwide cohort study using Centers for Disease Control and Prevention National Center for Health Statistics linked birth-infant death records for birth cohorts in 2015 through 2019. All US live births for the study years occurring at 28 weeks' gestation or later from complete reporting areas were eligible; SUID cases were deaths occurring at 7 to 364 days after birth with International Statistical Classification of Diseases, Tenth Revision cause of death code R95 (sudden infant death syndrome), R99 (ill-defined and unknown causes), or W75 (accidental suffocation and strangulation in bed). Data were analyzed from October 1 through November 15, 2023.

Exposure

Maternal prepregnancy body mass index (BMI; calculated as weight in kilograms divided by height in meters squared).

Main Outcome and Measure

SUID.

Results

Of 18 857 694 live births eligible for analysis (median [IQR] age: maternal, 29 [9] years; paternal, 31 [9] years; gestational, 39 [2] weeks), 16 545 died of SUID (SUID rate, 0.88/1000 live births). After confounder adjustment, compared with mothers with normal BMI (BMI 18.5-24.9), infants born to mothers with obesity had a higher SUID risk that increased with increasing obesity severity. Infants of mothers with class I obesity (BMI 30.0-34.9) were at increased SUID risk (adjusted odds ratio [aOR], 1.10; 95% CI, 1.05-1.16); with class II obesity (BMI 35.0-39.9), a higher risk (aOR, 1.20; 95% CI, 1.13-1.27); and class III obesity (BMI ≥40.0), an even higher risk (aOR, 1.39; 95% CI, 1.31-1.47). A generalized additive model showed that increased BMI was monotonically associated with increased SUID risk, with an acceleration of risk for BMIs greater than approximately 25 to 30. Approximately 5.4% of SUID cases were attributable to maternal obesity.

Conclusions and Relevance

The findings suggest that infants born to mothers with obesity are at increased risk of SUID, with a dose-dependent association between increasing maternal BMI and SUID risk. Maternal obesity should be added to the list of known risk factors for SUID. With maternal obesity rates increasing, research should identify potential causal mechanisms for this association.

The risk of sleep-related death in an inclined sleep environment

BACKGROUND

Unsafe sleep environments are the primary modifiable risk factor for sudden unexpected infant death (SUID). Despite this knowledge, products that deviate from the American Academy of Pediatrics (AAP) safe sleep recommendations continue to be commonplace, such as inclined sleepers. Analyses to estimate risk among these products are lacking, perpetuating their presence in the marketplace. We present a method of comparing risk of SUID in an inclined sleeper to an AAP-recommended sleep environment.

METHODS

A case-control analysis using publicly available and previously published survey data was conducted for SUID events occurring between January 1, 2018 and April 12, 2019 (the date of the first inclined sleeper recall). SUID deaths were categorized as occurring in an AAP-recommended sleep environments or in an inclined sleeper. Exposure Odds Ratios (OR) are reported as the risk of SUID among infants using inclined sleepers relative to an AAP-recommended sleep environment.

RESULTS

During the study period, 4,900,573 births and 4,363 SUID deaths occurred in the US. Control characteristics were similar between previous night users of an AAP-recommended sleep environment (24%) and inclined sleepers (3.8%). Inclined sleepers were associated with a 5-fold (OR: 5.1; 95% CI: 3.2, 7.9) increased risk of SUID among infants < 12 months compared to infants in an AAP-recommended sleep environment. This risk was greatest among infants ≥ 4 months (RR: 10.4; 95% CI: 5.1, 21.5).

CONCLUSIONS

This novel analysis fills a longstanding gap in risk assessments of inclined infant sleep products. More timely risk analyses may improve the safety of the marketplace.

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.

"Things changed very quickly": Maternal intentions and decision-making about infant sleep surface, location, and position

INTRODUCTION

Approximately 3400 infants die suddenly and unexpectedly each year in the United States; many of these deaths include modifiable risk factors (such as a non-supine position, sleeping on a soft surface, or loose bedding or items in the environment). Interventions have been successful at improving parental knowledge about recommendations to reduce risk of sleep-related infant deaths, as well as improving intention to adopt recommendations. However, follow-up studies have found a disconnect between knowledge/intentions to adhere to recommendations and actual practices. Exploring maternal decision-making about infant sleep practices can better elucidate the disconnect between knowledge of infant sleep recommendations and the practice of it, and thus, inform more effective safe sleep interventions. The purpose of this study was to gain a more in-depth understanding of decision-making around infant sleep practices, and barriers and facilitators to adopting safe infant sleep recommendations.

METHODS

Semi-structured in-home interviews were conducted with 22 families (20 mothers and 2 mother-father dyads) of infants up to 6 months of age.

RESULTS

Thematic analysis of the transcripts revealed six themes: Plans changed when baby came, Trying things to figure out what works (infant preferences), Safety concerns, What's comfortable for me (maternal preferences), They say…(advice), and Trying to be careful.

CONCLUSION

These results suggest that knowledge of infant sleep recommendations alone is not enough to ensure adherence and that decision-making is a dynamic and ongoing process affected by multiple factors. Findings have implications for timing and content of risk reduction efforts, as well as for data collection in research studies.

Characteristics of Sudden Unexpected Infant Deaths on Shared and Nonshared Sleep Surfaces

OBJECTIVES

Describe characteristics of sudden unexpected infant deaths (SUID) occurring on shared or nonshared sleep surfaces.

METHODS

We examined SUID among residents of 23 US jurisdictions who died during 2011 to 2020. We calculated frequencies and percentages of demographic, sleep environment, and other characteristics by sleep surface sharing status and reported differences of at least 5% between surface sharing and nonsharing infants.

RESULTS

Of 7595 SUID cases, 59.5% were sleep surface sharing when they died. Compared with nonsharing infants, sharing infants were more often aged 0 to 3 months, non-Hispanic Black, publicly insured, found supine, found in an adult bed or chair/couch, had a higher number of unsafe sleep factors present, were exposed to maternal cigarette smoking prenatally, were supervised by a parent at the time of death, or had a supervisor who was impaired by drugs or alcohol at the time of death. At least 76% of all SUID had multiple unsafe sleep factors present. Among surface-sharing SUID, most were sharing with adults only (68.2%), in an adult bed (75.9%), and with 1 other person (51.6%). Surface sharing was more common among multiples than singletons.

CONCLUSIONS

Among SUID, surface sharing and nonsharing infants varied by age at death, race and ethnicity, insurance type, presence of unsafe sleep factors, prenatal smoke exposure, and supervisor impairment. Most SUID, regardless of sleep location, had multiple unsafe sleep factors present, demonstrating the need for comprehensive safe sleep counseling for every family at every encounter.

Video Analyses of Sudden Unexplained Deaths in Toddlers

BACKGROUND AND OBJECTIVES

More than 2,900 US children aged younger than 4 years die from unknown causes each year, accounting for more than 219,000 life years lost annually. They are mostly sleep-related and unwitnessed with unremarkable autopsies, limiting our understanding of death mechanisms. We sought to understand potential mechanisms of death by evaluating videos of sudden deaths in toddlers.

METHODS

In our registry of 301 sudden unexplained child deaths, a series of 7 consecutively enrolled cases with home video recordings of the child's last sleep period were independently assessed by 8 physicians for video quality, movement, and sound.

RESULTS

Four boys and 3 girls (13-27 months at death) with terminal videos shared similar demographic features to the 293 other registry cases without video recordings. Five video recordings were continuous and 2 were triggered by sound or motion. Two lacked audio. All continuous recordings included a terminal convulsive event lasting 8-50 seconds; 4 children survived for >2.5 minutes postconvulsion. Among discontinuous videos, time lapses limited review; 1 suggested a convulsive event. Six were prone with face down, and 1 had autopsy evidence of airway obstruction. Primary cardiac arrhythmias were not supported; all 7 children had normal cardiac pathology and whole-exome sequencing identified no known cardiac disease variants.

DISCUSSION

Audio-visual recordings in 7 toddlers with unexplained sudden deaths strongly implicate that deaths were related to convulsive seizures, suggesting that many unexplained sleep-related deaths may result from seizures.

Forgotten Pediatrics: 8 Disturbing Windows on the Past

The 75 years since Pediatrics was first published has witnessed an explosion of the scientific knowledge base informing child health. Yet, the path leading to the present has not been linear. We examine several articles that illustrate some of the unexpected twists and turns that have characterized our specialty's history. We hope that it will provide a reminder of the ever-changing nature of scientific knowledge and the need to continually re-evaluate how our own cultural assumptions shape medical practice.

The fundamental need for unifying phenotypes in sudden unexpected pediatric deaths

A definitive, authoritative approach to evaluate the causes of unexpected, and ultimately unexplained, pediatric deaths remains elusive, relegating final conclusions to diagnoses of exclusion in the vast majority of cases. Research into unexplained pediatric deaths has focused primarily on sudden infant deaths (under 1 year of age) and led to the identification of several potential, albeit incompletely understood, contributory factors: nonspecific pathology findings, associations with sleep position and environment that may not be uniformly relevant, and the elucidation of a role for serotonin that is practically difficult to estimate in any individual case. Any assessment of progress in this field must also acknowledge the failure of current approaches to substantially decrease mortality rates in decades. Furthermore, potential commonalities with pediatric deaths across a broader age spectrum have not been widely considered. Recent epilepsy-related observations and genetic findings, identified post-mortem in both infants and children who died suddenly and unexpectedly, suggest a role for more intense and specific phenotyping efforts as well as an expanded role for genetic and genomic evaluation. We therefore present a new approach to reframe the phenotype in sudden unexplained deaths in the pediatric age range, collapsing many distinctions based on arbitrary factors (such as age) that have previously guided research in this area, and discuss its implications for the future of postmortem investigation.