Recent national trends in sudden, unexpected infant deaths: more evidence supporting a change in classification or reporting

National SIDS Trends in the United States From 2000 to 2019: A Population-Based Study on 80 Million Live Births

Sudden infant death syndrome (SIDS) is the most common cause of death for infants between 1 month and 1 year of age in the United States. The objective was to examine recent trends in SIDS in the United States, over time and by sex and race. A population-based cross-sectional study was conducted on 80 710 348 live births using data from the Center for Disease Control and Prevention's (CDC) "Birth Data" and "Mortality Multiple Cause" files from 2000 to 2019. Logistic regression examined the effects of sex and race on the risk of SIDS and examined temporal changes in risk across sex and race over the study period. Incidence of SIDS decreased from 6.3 to 3.4/10 000 births from 2000 to 2019, with an overall incidence of 4.9/10 000 births (95% confidence interval [CI] = 4.4-5.3). Male infants were at the greatest risk of SIDS as were black and American Indian infants. Although SIDS incidence decreased by sex and race over time, the decline was smaller among Hispanic and American Indian infants.

Understanding three approaches to reporting sudden unexpected infant death in the USA

INTRODUCTION

In the USA each year, there are approximately 3400 sudden unexpected infant (<1 year of age) deaths (SUID) which occur without an obvious cause before an investigation. SUID includes the causes of death (COD) undetermined/unknown, sleep-related suffocation/asphyxia and sudden infant death syndrome (SIDS); these are often called SUID subtypes. Three common ways SUID subtypes are grouped (SUID subtype groups) include International Classification of Diseases (ICD) Codes, SUID Case Registry Categories or Child Death Review (CDR)-Assigned Causes. These groups are often used to monitor SUID trends and characteristics at the local, state and national levels. We describe and compare the characteristics of these three SUID subtype groups.

DISCUSSION

SUID subtype groups are distinct and not directly interchangeable. They vary in purpose, strengths, limitations, uses, history, data years available, population coverage, assigning entity, guidance documentation and information available to assign subtypes.

CONCLUSION

Making informed decisions about which SUID subtype group to use is important for reporting statistics, increasing knowledge of SUID epidemiology and informing prevention strategies.

Organ weights and length anthropometry measures at autopsy for sudden infant death syndrome cases and other infant deaths in the Chicago infant mortality study

Organ weights are a possible diagnostic or pathophysiological clue to distinguishing sudden infant death syndrome (SIDS) cases from other infant deaths but suffer from major confounding. Using autopsy data from the Chicago Infant Mortality Study, a majority African-American case-control study of deceased infants under 1 year conducted 1993-96, we assessed differences in the weights of brain, thymus, kidneys, lungs, liver, spleen, total body, and four length anthropometry measures in SIDS-diagnosed infants compared to controls. Using exact and coarsened matching, we ran Bayesian linear models with these anthropometry outcomes and repeated the analyses substituting the corresponding fitted allometrically-scaled organ weight indices to account for body size. After detailed analysis and adjustment for potential confounders, we found that matched SIDS infants were generally bigger than controls, with higher mean brain, liver, spleen, thymus, lung, and total body weights, and higher mean head and chest circumference, crown-heel, crown-rump lengths. SIDS infants also had higher mean thymus, liver, spleen, lung and total body weight indices. The association with thymus weight was proportionately greater in magnitude than any other outcome measure and independent of body size. The results of these more detailed analyses are consistent with recent findings from other studies with differing racial compositions, and substantially confirm the primary organ sites for more detailed mechanistic research into the biological dysregulation contributing to underlying pathophysiology of SIDS.

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.

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.

Sudden Infant Death Syndrome: Risk Factors and Newer Risk Reduction Strategies

Sudden infant death syndrome (SIDS) continues to be one of the top causes of infant death in the U.S. Despite significant public health initiatives focused on high-risk populations to enhance sleep environments and techniques. The SIDS rate has remained stable in recent years. Risk factors and newer risk reduction strategies for SIDS are the focus of this review article. We conducted a comprehensive literature search on Medline, Cochrane, Embase, and Google Scholar until July 2022. The following search strings and Medical Subject Heading (MeSH) terms were used: "SIDS," "Sudden Infant Death" and "SUID". We explored the literature on SIDS for its epidemiology, pathophysiology, the role of various etiologies and their influence, associated complications leading to SIDS, and preventive and treatment modalities. Despite a more than 50% drop-in rates since the start of the "Back to Sleep" campaign in 1994, sudden infant death syndrome (SIDS) continues to be the top cause of post-neonatal mortality in the United States, despite continued educational initiatives that support safe sleep and other risk reduction strategies. The new American Academy of Pediatrics guidelines for lowering the risk of SIDS include a lot of emphasis on sleeping habits, bedding, and environment but also include elements that are frequently ignored (i.e., prenatal care, smoking, alcohol and drug use, and childhood vaccinations). This study highlights these less-frequently discussed aspects and identifies treatments that have produced beneficial behavioral shifts that benefit newborns as well as their mothers' health and wellbeing.

Sudden Unexpected Infant Deaths: 2015-2020

OBJECTIVE

Although the US infant mortality rate reached a record low in 2020, the sudden infant death syndrome (SIDS) rate increased from 2019. To understand if the increase was related to changing death certification practices or the coronavirus disease 2019 (COVID-19) pandemic, we examined sudden unexpected infant death (SUID) rates as a group, by cause, and by race and ethnicity.

METHODS

We estimated SUID rates during 2015 to 2020 using US period-linked birth and death data. SUID included SIDS, unknown cause, and accidental suffocation and strangulation in bed. We examined changes in rates from 2019 to 2020 and assessed linear trends during prepandemic (2015-2019) using weighted least squares regression. We also assessed race and ethnicity trends and quantified COVID-19-related SUID.

RESULTS

Although the SIDS rate increased significantly from 2019 to 2020 (P < .001), the overall SUID rate did not (P = .24). The increased SIDS rate followed a declining linear trend in SIDS during 2015 to 2019 (P < .001). Other SUID causes did not change significantly. Our race and ethnicity analysis showed SUID rates increased significantly for non-Hispanic Black infants from 2019 to 2020, widening the disparities between these two groups during 2017 to 2019. In 2020, <10 of the 3328 SUID had a COVID-19 code.

CONCLUSIONS

Diagnositic shifting likely explained the increased SIDS rate in 2020. Why the SUID rate increased for non-Hispanic Black infants is unknown, but warrants continued monitoring. Interventions are needed to address persistent racial and ethnic disparities in SUID.

Risk Factors for Suffocation and Unexplained Causes of Infant Deaths

BACKGROUND

Observational studies have improved our understanding of the risk factors for sudden infant death syndrome, but separate examination of risk for sleep-related suffocation and unexplained infant deaths has been limited. We examined the association between unsafe infant sleep practices and sudden infant deaths (sleep-related suffocation and unexplained causes including sudden infant death syndrome).

METHODS

We conducted a population-based case-control study using 2016 to 2017 Centers for Disease Control and Prevention data. Controls were liveborn infants from the Pregnancy Risk Assessment Monitoring System; cases were from the Sudden Unexpected Infant Death Case Registry. We calculated risk factor prevalence among cases and controls and crude and adjusted odds ratios.

RESULTS

We included 112 sleep-related suffocation cases with 448 age-matched controls and 300 unexplained infant death cases with 1200 age-matched controls. Adjusted odds for sleep-related suffocation ranged from 18.7 (95% confidence interval [CI]: 6.8-51.3) among infants not sharing a room with their mother or caregiver to 1.9 (95% CI: 0.9-4.1) among infants with nonsupine sleep positioning. Adjusted odds for unexplained death ranged from 7.6 (95% CI: 4.7-12.2) among infants not sharing a room with their mother or caregiver to 1.6 (95% CI: 1.1-2.4) among nonsupine positioned infants.

COCLUSIONS

We confirmed previously identified risk factors for unexplained infant death and independently estimated risk factors for sleep-related suffocation. Significance of associations for suffocation followed similar patterns but was of larger magnitude. This information can be used to improve messaging about safe infant sleep.

Maternal, infant, and environmental risk factors for sudden unexpected infant deaths: results from a large, administrative cohort

OBJECTIVES

Many studies of sudden unexpected infant death (SUID) have focused on individual domains of risk factors (maternal, infant, and environmental), resulting in limited capture of this multifactorial outcome. The objective of this study was to examine the geographic distribution of SUID in San Diego County, and assess maternal, infant, and environmental risk factors from a large, administrative research platform.

STUDY DESIGN

Births in California between 2005 and 2017 were linked to hospital discharge summaries and death files. From this retrospective birth cohort, cases of SUID were identified from infant death files in San Diego County. We estimated adjusted hazard ratios (aHRs) for infant, maternal, and environmental factors and SUID in multivariable Cox regression analysis. Models were adjusted for maternal sociodemographic characteristics and prenatal nicotine exposure.

RESULTS

There were 211 (44/100,000 live births; absolute risk 0.04%) infants with a SUID among 484,905 live births. There was heterogeneity in geographic distribution of cases. Multiparity (0.05%; aHR 1.4, 95% confidence interval (CI) 1.1, 1.9), maternal depression (0.11%; aHR 1.8, 95% CI 1.0, 3.4), substance-related diagnoses (0.27%; aHR 2.3, 95% CI 1.3, 3.8), cannabis-related diagnosis (0.35%; aHR 2.7, 95% CI 1.5, 5.0), prenatal nicotine use (0.23%; aHR 2.5, 95% CI 1.5, 4.2), preexisting hypertension (0.11%; aHR 2.3, 95% CI 1.2, 4.3), preterm delivery (0.09%; aHR 2.1, 95% CI 1.5, 3.0), infant with a major malformation (0.09%; aHR 2.0, 95% CI 1.1, 3.6), respiratory distress syndrome (0.12%; aHR 2.6, 95% CI 1.5, 4.6), and select environmental factors were all associated with SUID.

CONCLUSIONS

Multiple risk factors were confirmed and expanded upon, and the geographic distribution for SUID in San Diego County was identified. Through this approach, prevention efforts can be targeted to geographies that would benefit the most.

The global burden of sudden infant death syndrome from 1990 to 2019: a systematic analysis from the Global Burden of Disease study 2019

BACKGROUND

Sudden infant death syndrome (SIDS) still remains one of the leading causes of infant death worldwide, especially in high-income countries. To date, however, there is no detailed information on the global health burden of SIDS.

AIMS

To characterize the global disease burden of SIDS and its trends from 1990 to 2019 and to compare the burden of SIDS according to the socio-demographic index (SDI).

DESIGN

Systematic analysis based on the Global Burden of Disease (GBD) 2019 data.

METHODS

Epidemiological data of 204 countries from 1990 to 2019 were collected via various methods including civil registration and vital statistics in the original GBD study. Estimates for mortality and disease burden of SIDS were modeled. Crude mortality and mortality rates per 100 000 population were analyzed. Disability-adjusted life years (DALYs) and DALY rates were also assessed.

RESULTS

In 2019, mortality rate of SIDS accounted for 20.98 [95% Uncertainty Interval, 9.15-46.16] globally, which was a 51% decrease from 1990. SIDS was most prevalent in Western sub-Saharan Africa, High-income North America and Oceania in 2019. The burden of SIDS was higher in males than females consistently from 1990 to 2019. Higher SDI and income level was associated with lower burden of SIDS; furthermore, countries with higher SDI and income had greater decreases in SIDS burden from 1990 to 2019.

CONCLUSIONS

The burden of SIDS has decreased drastically from 1990 to 2019. However, the improvements have occurred disproportionately between regions and SDI levels. Focused preventive efforts in under-resourced populations are needed.

Important Advances in Pediatric Injury Prevention

In children, injuries are the leading cause of death, a major source of disability, and the number one cause of death for children after the first year of life. The principles of injury prevention include surveillance, coalitions, communication, interventions, and evaluation. This article discusses a number of common pediatric injuries and their prevention strategies. This review article addresses key components of injury prevention and specifically addresses the following injuries: motor vehicle crashes (with a section on teen driver crashes, sleep-related injury, and death), poisoning, all-terrain vehicle crashes, drowning, and firearm injuries. Injuries are preventable occurrences that can result in devastating sequelae or death. We present an overview of the more common pediatric injuries along with injury-prevention strategies.

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.

A proof-of-concept study to construct Bayesian network decision models for supporting the categorization of sudden unexpected infant death

Sudden infant death syndrome (SIDS) remains a leading cause of infant death in high-income countries. Supporting models for categorization of sudden unexpected infant death into SIDS/non-SIDS could reduce mortality. Therefore, we aimed to develop such a tool utilizing forensic data, but the reduced number of SIDS cases renders this task inherently difficult. To overcome this, we constructed Bayesian network models according to diagnoses performed by expert pathologists and created conditional probability tables in a proof-of-concept study. In the diagnostic support model, the data of 64 sudden unexpected infant death cases was employed as the training dataset, and 16 known-risk factors, including age at death and co-sleeping, were added. In the validation study, which included 8 new cases, the models reproduced experts’ diagnoses in 4 or 5 of the 6 SIDS cases. Next, to confirm the effectiveness of this approach for onset prediction, the data from 41 SIDS cases was employed. The model predicted that the risk of SIDS in 0- to 2-month-old infants exposed to passive smoking and co-sleeping is eightfold higher than that in the general infant population, which is comparable with previously published findings. The Bayesian approach could be a promising tool for constructing SIDS prevention models.

Cerebrospinal Fluid Histamine Levels in Healthy Children and Potential Implication for SIDS: Observational Study in a French Tertiary Care Hospital

OBJECTIVE

A defect of the waking systems could constitute a factor of vulnerability for sudden infant death syndrome (SIDS). A decrease in orexin levels, which promotes wakefulness and activates histaminergic neurons (another hypothalamic wake-promoting system) has already been demonstrated between 2 and 6 months. This work aims to study the levels of histamine (HA), tele-methylhistamine (t-MeHA), its direct metabolite, and t-MeHA/HA ratio in the cerebrospinal fluid (CSF) of healthy children, to evaluate the maturation of the histaminergic system and its possible involvement in SIDS.

METHODS

Seventy Eight French children between 0 and 20 years (48.7% boys) were included, all of whom had a clinical indication for lumbar puncture, but subsequently found to be normal. Measurements of HA and t-MeHA in CSF were performed by reverse phase liquid chromatography coupled to mass spectrometry detection. Statistical analyses were performed using Spearman correlations and Non-parametric pairwise ranking tests.

RESULTS

A negative correlation was found between age and CSF HA (r = -0.44, p < 10^-4) and t-MeHA (r = -0.70, p < 10^-4) levels. In pairwise comparisons, no difference in CSF HA and t-MeHA levels was observed between youngest age groups (i.e., 0-2 mo vs. 3-6 mo), but CSF HA and t-MeHA levels were significantly lower in older children (i.e., >6 mo vs. 0-6 mo). The CSF HA decrease with age was only observed in boys, who also presented global lower CSF HA levels than girls.

CONCLUSION

CSF HA and t-MeHA levels decrease with age in boys, and global levels are lower in boys than in girls. These results reveal changes in histaminergic transmission and metabolism during maturation. Whether lower CSF histamine values in boys compared to girls could contribute to their higher risk of SIDS warrants further research.

Epidemiology of sudden infant death syndrome in Mexico, 2005-2020

BACKGROUND

Sudden Infant Death Syndrome (SIDS) constitutes one of the main causes of mortality in children under one year of age in developed countries; it's frequency to varies geographically. In Mexico the real incidence of SIDS is not known.

METHODS

National databases of deaths in children under one year of age, from 2005 to 2020, were analyzed, due to Sudden Unexpected Infant Death (SUID) [SIDS (R95), accidental suffocation in a sleeping environment (W75), and other ill-defined and unspecified causes of mortality (R99), according to the International Classification of Diseases, tenth revision (ICD 10)]. Mortality rates per year of occurrence due to SUID and their subcategories were calculated. Simple frequencies of SIDS were obtained per year and month of occurrence, state of residence, age, place of death, and access to social security services.

RESULTS

In the study period 473,545 infant deaths occurred; 7,714 (1.62%) deaths were due to SUID; of these, 6,489 (84%) were due to SIDS, which is among the 10 leading causes of infant death in Mexico. The average mortality rate for SUID was 22.4/100,000 live births, for SIDS was 18.8/100,000 live births. Mortality rates within the states were variable, ranging from 2.4/100,000 to 105.1/100,000 live births. In 81% of SIDS records there was no autopsy; 38% of deaths due to SIDS occurred in infants under one month of age, up to 87% of deaths occurred in families without social security services or it was unknown, and 76.2% of deaths occurred at home. Deaths were more frequent during the last months of autumn and during winter.

CONCLUSION

In Mexico there is an underregistry of SIDS as cause of death, along with other SUID categories. Health workers need to be trained to improve diagnosis and data registration, including the practice of autopsies; additionally, it is necessary to implement a public health campaign.

Improving Adherence to Safe Sleep Guidelines for Hospitalized Infants at a Children’s Hospital

Supplemental Digital Content is available in the text.

Introduction:

Sudden unexpected infant deaths are a major problem nationally. We had poor adherence to safe sleep recommendations locally at our institution. Given the significance of this problem, hospital administration at a tertiary children’s hospital tasked a multidisciplinary group of faculty and staff with improving sleep environments for hospitalized infants.

Methods:

Our safe sleep task force implemented targeted interventions using the American Academy of Pediatrics policy statement as the gold standard and based on hospital data to address areas of greatest nonadherence to recommendations. We aimed to improve weekly average adherence to 95% over 12 months. A proportions process control chart (p-chart) tracked average weekly adherence over a 52-week time frame. In addition, we performed Student’s t-testing to evaluate differences in adherence over time.

Results:

There was a significant improvement in overall adherence to safe sleep recommendations from baseline (M = 70.8%, SD 21.6) to end of study period (M = 94.7%, SD 10.0) [t(427) = −15.1, P ≤ 0.001]. Crib audits with 100% adherence increased from a baseline (M = 0%, SD 0) to the end of the study period M = 70.4%, SD = 46) [t(381)= −21.4, P ≤ 0.001]. This resulted in two trend shifts on the p-chart using Institute for Healthcare Improvement control chart rules.

Conclusions:

Targeted interventions using QI methodology led to significant increases in adherence to safe sleep guidelines. Notable improvements in behavior indicated significant changes in safe sleep culture. We also noted continued adherence in follow-up audits reflecting sustainability.

Breastfeeding and post-perinatal infant deaths in the United States, A national prospective cohort analysis

Background

Reducing infant mortality is a major public health goal. The potential impact of breastfeeding on infant deaths is not well studied in the United States (US).

Methods

We analyzed linked birth-death certificates for 3,230,500 US births that occurred in 2017, including 6,969 post-perinatal deaths from 7-364 days of age as the primary outcome, further specified as late-neonatal (7-27 days) or post-neonatal (28-364 days) deaths. The primary exposure was 'ever breastfed' obtained from birth certificates. Multiple logistic regression examined associations of ever breastfeeding with post-perinatal deaths and specific causes of deaths, controlling for maternal and infant factors.

Findings

We observed an adjusted reduced odds ratio (AOR)= 0·74 with 95% confidence intervals (CI)=0·70-0·79 for the association of breastfeeding initiation with overall infant deaths (7-364 days), AOR=0·60 (0·54-0·67) for late-neonatal deaths, and AOR=0·81 (0·76-0·87) for post-neonatal deaths. In race/ethnicity-stratified analysis, significant associations of breastfeeding initiation with reduced odds of overall infant deaths were observed for Hispanics [AOR=0·64 (0·55-0·74)], non-Hispanic Whites [AOR=0·75 (0·69-0·81)], non-Hispanic Blacks [AOR=0·83 (0·75-0·91)], and non-Hispanic Asians [AOR=0·51 (0·36-0·72)]. Across racial/ethnic groups, effect sizes for late-neonatal deaths were consistently larger than those for post-neonatal deaths. Significant effects of breastfeeding initiation were observed for deaths due to infection [AOR=0·81(0·69-0·94)], Sudden Unexpected Infant Death [AOR=0·85 (0·78-0·92)], and necrotizing enterocolitis [AOR=0·67 (0·49-0·90)].

Interpretation

Breastfeeding initiation is significantly associated with reduced odds of post-perinatal infant deaths in multiple racial and ethnic groups within the US population. These findings support efforts to improve breastfeeding in infant mortality reduction initiatives.

Social and environmental risk factors for unintentional suffocation among infants in China: a descriptive analysis

Background

This retrospective study aimed to determine the epidemiological features of deaths caused by unintentional suffocation among infants in China.

Methods

The data used in this study were obtained from China’s Under 5 Child Mortality Surveillance System (U5CMSS) from October 1, 2015, to September 30, 2016. A total of 377 children under 1 year of age who died from unintentional suffocation were included in the survey. Primary caregivers were interviewed individually using the Unintentional Suffocation Mortality among Children under 5 Questionnaire. EpiData was used to establish the database, and the results were analysed using SPSS 22.0.

Results

Most (85.9%) unintentional infant suffocations occurred in rural areas, and 67.5% occurred in infants 0 to 3 months old. Among the primary caregivers of the infants, most (82.7%) had a junior middle school education or below, and 83.1% of them lacked unintentional suffocation first aid skills. Of the 377 unintentional suffocated-infant deaths, the causes of death were accidental suffocation and strangulation in bed (ASSB) (193, 51.2%), inhalation suffocation (154, 40.8%), other unintentional suffocation (6, 1.6%), and unknown (24, 6.4%). Among the infant deaths due to ASSB, overlaying (88.6%) was the most frequently reported circumstance. A total of 93.8% of cases reported occurred during co-sleeping/bed sharing with parents, and in 72.8% of the cases, the infants were covered with the same quilt as their parents. In our study, most inhalation suffocation deaths (88.3%) involved liquid food (such as breast milk and formula milk). A total of 80.5% of infant deaths reportedly occurred after eating; in 28.2% of those cases, the infants were held upright and patted by their caregivers, and 57.2% of them were laid down to sleep immediately after eating.

Conclusions

To reduce the occurrence of unintentional suffocation, local government should strengthen knowledge and awareness of unintentional suffocation prevention and safety among parents and caregivers. Additionally, health care providers should educate parents and caregivers about safety issues of unintentional suffocation, and relevant policies should be introduced to provide environments and activities that reduce the risk of suffocation, such as promoting the Safe to Sleep Campaign. It is important to enhance the focus on infant unintentional suffocation as a health issue.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02925-4.

Half Century Since SIDS: A Reappraisal of Terminology

After a sudden infant death, parents and caregivers need accurate and open communication about why their infant died. Communicating tragic news about a child's death to families and caregivers is difficult. Shared and consistent terminology is essential for pediatricians, other physicians, and nonphysician clinicians to improve communication with families and among themselves. When families do not have complete information about why their child died, pediatricians will not be able to support them through the process and make appropriate referrals for pediatric specialty and mental health care. Families can only speculate about the cause and may blame themselves or others for the infant's death. The terminology used to describe infant deaths that occur suddenly and unexpectedly includes an assortment of terms that vary across and among pediatrician, other physician, or nonphysician clinician disciplines. Having consistent terminology is critical to improve the understanding of the etiology, pathophysiology, and epidemiology of these deaths and communicate with families. A lack of consistent terminology also makes it difficult to reliably monitor trends in mortality and hampers the ability to develop effective interventions. This report describes the history of sudden infant death terminology and summarizes the debate over the terminology and the resulting diagnostic shift of these deaths. This information is to assist pediatricians, other physicians, and nonphysician clinicians in caring for families during this difficult time. The importance of consistent terminology is outlined, followed by a summary of progress toward consensus. Recommendations for pediatricians, other physicians, and nonphysician clinicians are proposed.

Sudden Unexpected Infant Death: Keeping the Newborn Safe in Hospital and at Home

Sudden unexpected infant death is a leading cause of death in infancy. Both safe sleep practices and breastfeeding can help decrease the risk, although the current practice of educating parents about the recommendations has not resulted in universal adherence. Prenatal counseling provides opportunities to discuss recommendations as well as troubleshoot common barriers to breastfeeding and safe infant sleep with goals to gradually change attitudes, address social norms, and prepare new parents. A conversational, motivational approach to discussions about the importance of safe sleep and continued breastfeeding, with explanations as to the reasoning behind these recommendations, can help parents incorporate optimal practices into their lifestyles in a way that is sustainable for adherence.

Explaining Sudden Unexpected Infant Deaths, 2011-2017

BACKGROUND

Sudden unexpected infant death (SUID) represents a broad group of explained and unexplained infant deaths (<1 year old). Explaining why SUID occurs is critical to understanding etiology and prevention. Death certificate data cannot differentiate explained from unexplained SUID cases nor describe the surrounding circumstances. We report SUID rates by explained and unexplained categories and describe demographics and history of recent injury or illness using the Centers for Disease Control and Prevention SUID Case Registry.

METHODS

The registry is a population-based surveillance system built on Child Death Review programs. Data are derived from multiple sources, including death certificates, scene investigations, and autopsy reports. Cases included SUIDs reported by states or jurisdictions participating in the registry during 2011-2017. Cases were classified into explained and unexplained categories by using the registry's classification system. Frequencies, percentages, and mortality rates per 100 000 live births were calculated.

RESULTS

Of the 4929 SUID cases, 82% were categorized as unexplained. Among all cases, 73% had complete case information. Most SUIDs (72%) occurred in an unsafe sleep environment. The SUID mortality rate was 97.3 per 100 000 live births. Among explained and possible suffocation deaths, ∼75% resulted from airway obstruction attributed to soft bedding.

CONCLUSIONS

Unsafe sleep factors were common in explained and unexplained SUID cases, but deaths could only be classified as explained suffocation for ∼20% of cases. Further analysis of unexplained deaths, including continued improvements to death scene investigation and documentation, may generate hypotheses for physiologic and genetic research, advance our understanding of gaps in SUID investigation, and enhance our understanding of infants at highest risk.

Sudden Infant Death Syndrome: Beyond Risk Factors

Sudden infant death syndrome (SIDS) is defined as "the sudden death of an infant under 1 year of age which remains unexplained after thorough investigation including a complete autopsy, death scene investigation, and detailed clinical and pathological review". A significant decrease of SIDS deaths occurred in the last decades in most countries after the beginning of national campaigns, mainly as a consequence of the implementation of risk reduction action mostly concentrating on the improvement of sleep conditions. Nevertheless, infant mortality from SIDS still remains unacceptably high. There is an urgent need to get insight into previously unexplored aspects of the brain system with a special focus on high-risk groups. SIDS pathogenesis is associated with a multifactorial condition that comprehends genetic, environmental and sociocultural factors. Effective prevention of SIDS requires multiple interventions from different fields. Developing brain susceptibility, intrinsic vulnerability and early identification of infants with high risk of SIDS represents a challenge. Progress in SIDS research appears to be fundamental to the ultimate aim of eradicating SIDS deaths. A complex model that combines different risk factor data from biomarkers and omic analysis may represent a tool to identify a SIDS risk profile in newborn settings. If high risk is detected, the infant may be referred for further investigations and follow ups. This review aims to illustrate the most recent discoveries from different fields, analyzing the neuroanatomical, genetic, metabolic, proteomic, environmental and sociocultural aspects related to SIDS.

Altitude and risk of sudden unexpected infant death in the United States

The effect of altitude on the risk of sudden infant death syndrome (SIDS) has been reported previously, but with conflicting findings. We aimed to examine whether the risk of sudden unexpected infant death (SUID) varies with altitude in the United States. Data from the Centers for Disease Control and Prevention (CDC)'s Cohort Linked Birth/Infant Death Data Set for births between 2005 and 2010 were examined. County of birth was used to estimate altitude. Logistic regression and Generalized Additive Model (GAM) were used, adjusting for year, mother's race, Hispanic origin, marital status, age, education and smoking, father's age and race, number of prenatal visits, plurality, live birth order, and infant's sex, birthweight and gestation. There were 25,305,778 live births over the 6-year study period. The total number of deaths from SUID in this period were 23,673 (rate = 0.94/1000 live births). In the logistic regression model there was a small, but statistically significant, increased risk of SUID associated with birth at > 8000 feet compared with < 6000 feet (aOR = 1.93; 95% CI 1.00-3.71). The GAM showed a similar increased risk over 8000 feet, but this was not statistically significant. Only 9245 (0.037%) of mothers gave birth at > 8000 feet during the study period and 10 deaths (0.042%) were attributed to SUID. The number of SUID deaths at this altitude in the United States is very small (10 deaths in 6 years).

Factors associated with age of death in sudden unexpected infant death

Aim

This study aimed to systematically analyse the pregnancy, birth and demographic‐related factors associated with age of death in sudden unexpected infant death (SUID).

Methods

Data were analysed from the Centers for Disease Control and Prevention's Cohort Linked Birth/Infant Death data set (2011‐2013; 11 737 930 live births). SUID was defined as deaths from sudden infant death syndrome, ill‐defined causes, or accidental suffocation and strangulation in bed. There were 9668 SUID cases (7‐364 days; gestation >28 weeks; 0.82/1000 live births). The odds of death at different ages were compared to determine which variables significantly affect the SUID age of death.

Results

Forty‐three features indicated a significant change in age of death with two main patterns: (a) younger chronologic age at death was associated with maternal smoking and factors associated with lower socio‐economic status, and (b) older age was associated with low birthweight, prematurity and admission to the neonatal intensive care unit. However, when age was corrected for gestation, these factors were associated with younger age.

Conclusion

Factors that varied with age of death are well‐documented risk factors for SUID. The majority of these risk factors were associated with younger age at death after allowing for gestational age at birth.

Revisiting the Neuropathology of Sudden Infant Death Syndrome (SIDS)

Background: Sudden infant death syndrome (SIDS) is one of the leading causes of infant mortality in the United States (US). The extent to which SIDS manifests with an underlying neuropathological mechanism is highly controversial. SIDS correlates with markers of poor prenatal and postnatal care, generally rooted in the lack of access and quality of healthcare endemic to select racial and ethnic groups, and thus can be viewed in the context of health disparities. However, some evidence suggests that at least a subset of SIDS cases may result from a neuropathological mechanism. To explain these issues, a triple-risk hypothesis has been proposed, whereby an underlying biological abnormality in an infant facing an extrinsic risk during a critical developmental period SIDS is hypothesized to occur. Each SIDS decedent is thus thought to have a unique combination of these risk factors leading to their death. This article reviews the neuropathological literature of SIDS and uses machine learning tools to identify distinct subtypes of SIDS decedents based on epidemiological data.

Methods: We analyzed US Period Linked Birth/Infant Mortality Files from 1990 to 2017 (excluding 1992–1994). Using t-SNE, an unsupervised machine learning dimensionality reduction algorithm, we identified clusters of SIDS decedents. Following identification of these groups, we identified changes in the rates of SIDS at the state level and across three countries.

Results: Through t-SNE and distance based statistical analysis, we identified three groups of SIDS decedents, each with a unique peak age of death. Within the US, SIDS is geographically heterogeneous. Following this, we found low birth weight and normal birth weight SIDS rates have not been equally impacted by implementation of clinical guidelines. We show that across countries with different levels of cultural heterogeneity, reduction in SIDS rates has also been distinct between decedents with low vs. normal birth weight.

Conclusions: Different epidemiological and extrinsic risk factors exist based on the three unique SIDS groups we identified with t-SNE and distance based statistical measurements. Clinical guidelines have not equally impacted the groups, and normal birth weight infants comprise more of the cases of SIDS even though low birth weight infants have a higher SIDS rate.

National Variations in Recent Trends of Sudden Unexpected Infant Death Rate in Western Europe

OBJECTIVE

To study recent epidemiologic trends of sudden unexpected death in infancy (SUDI) in Western Europe.

STUDY DESIGN

Annual national statistics of death causes for 14 Western European countries from 2005 to 2015 were analyzed. SUDI cases were defined as infants younger than 1 year with the underlying cause of death classified as "sudden infant death syndrome," "unknown/unattended/unspecified cause," or "accidental threats to breathing." Poisson regression models were used to study temporal trends of SUDI rates and source of variation.

RESULTS

From 2005 to 2015, SUDI accounted for 15 617 deaths, for an SUDI rate of 34.9 per 100 000 live births. SUDI was the second most common cause of death after the neonatal period (22.2%) except in Belgium, Finland, France, and the UK, where it ranked first. The overall SUDI rate significantly decreased from 40.2 to 29.9 per 100 000, with a significant rate reduction experienced for 6 countries, no significant evolution for 7 countries, and a significant increase for Denmark. The sudden infant death syndrome/SUDI ratio was 56.7%, with a significant decrease from 64.9% to 49.7% during the study period, and ranged from 6.1% in Portugal to 97.8% in Ireland. We observed between-country variations in SUDI and sudden infant death syndrome sex ratios.

CONCLUSIONS

In studied countries, SUDI decreased during the study period but remained a major cause of infant deaths, with marked between-country variations in rates, trends, and components. Standardization is needed to allow for comparing data to improve the implementation of risk-reduction strategies.

Improving infant sleep safety via electronic health record communication: a randomized controlled trial

BACKGROUND

With increased use of telehealth, interventions to improve infant sleep environments have not been explored. This study sought to assess the feasibility and efficacy of using electronic health record patient portals to transmit photographs of infant sleep between mothers and healthcare professionals as part of an intervention to promote sleep environments consistent with AAP guidelines.

METHODS

One hundred eighty-four mother-newborn dyads consented to participate in a randomized trial requiring patient portal registration within 1 month of delivery. We first assessed feasibility as measured by a) the proportion of consented mothers enrolling in the portal and b) maternal adherence to prompts to submit photographs of their infant sleeping to the research team through the patient portal. Intervention group mothers were prompted at 1 and 2 months; controls were prompted only at 2 months. Efficacy was determined via research assistant review of submitted photographs. These assistants were trained to detect sudden unexplained infant death risk factors utilizing AAP guidelines. Standardized feedback was returned to mothers through the patient portal. We used Fisher's Exact test to assess group differences in guideline adherence at 2 months.

RESULTS

One hundred nine mothers (59%) enrolled in the patient portal and were randomized to intervention (N = 55) and control (N = 54) groups. 21 (38, 95% CI 25-52%) intervention group participants sent photographs at 1 month and received personalized feedback. Across both groups at 2 months, 40 (37, 95% CI 28-46%) sent photographs; 56% of intervention group participants who submitted photographs met all safe sleep criteria compared with 46% of controls (difference 0.10, 95% CI - 0.26 to 0.46, p = .75). Common reasons for guideline non-adherence were sleeping in a room without a caregiver (43%), loose bedding (15%) and objects (8%) on the sleep surface.

CONCLUSIONS

Utilizing the patient portal to individualize safe infant sleep is possible, however, we encountered numerous barriers in this trial to assess its effects on promoting safe infant sleep. Photographs of infants sleeping showed substantial non-adherence to AAP guidelines, suggesting further needs for improvement to promote safe infant sleep practices.

TRIAL REGISTRATION

Name: Improving Infant Sleep Safety With the Electronic Health Record; Clinicaltrials.gov: NCT03662048 ; Date of Registration: September 7, 2018; Data Sharing Statement: None.

International time trends in sudden unexpected infant death, 1969-2012

Background

Sudden unexpected infant death (SUID) - including sudden infant death syndrome (SIDS) - continues to be a major contributor to infant mortality worldwide. Our objective was to analyse time trends and to identify country-clusters.

Methods

The National Statistical Offices of 52 countries provided the number of deaths and live births (1969–2012). We calculated infant mortality rates per 1000 live births for SUID, SIDS, and all-cause mortality. Overall, 29 countries provided sufficient data for time course analyses of SUID. To sensitively model change over time, we smoothed the curves of mortality rates (1980–2010). We performed a hierarchical cluster analysis to identify clusters of time trends for SUID and SIDS, including all-cause infant mortality.

Results

All-cause infant mortality declined from 28.5 to 4.8 per 1000 live births (mean 12.4; 95% confidence interval 12.0–12.9) between 1969 and 2012. The cluster analysis revealed four country-clusters. Clusters 1 and 2 mostly contained countries showing the typical peak of SUID mortality during the 1980s. Cluster 1 had higher SUID mortality compared to cluster 2. All-cause infant mortality was low in both clusters but higher in cluster 1 compared to cluster 2. Clusters 3 and 4 had low rates of SUID without a peak during the 1980s. Cluster 3 had the highest all-cause infant mortality of all clusters. Cluster 4 had an intermediate all-cause infant mortality. The time trends of SUID and SIDS mortality were similar.

Conclusions

The country-specific time trends in SUID varied considerably. The identification of country-clusters may promote research into how changes in sleep position, smoking, immunisation, or other factors are related to our findings.

Geographic Variation in Sudden Unexpected Infant Death in the United States

OBJECTIVES

To assess the geographic variation of sudden unexpected infant death (SUID) and test if variation in geographic factors, such as state, latitude, and longitude, play a role in SUID risk across the US.

STUDY DESIGN

We analyzed the Centers for Disease Control and Prevention's Cohort Linked Birth/Infant Death dataset (2005-2010; 22 882 SUID cases, 25 305 837 live births, rate 0.90/1000). SUID was defined as infant deaths (ages 7-364 days) that included sudden infant death syndrome, ill-defined and unknown cause of mortality, and accidental suffocation and strangulation in bed. SUID geographic variation was analyzed using 2 statistical models, logistic regression and generalized additive model (GAM).

RESULTS

Both models produced similar results. Without adjustment, there was marked geographic variation in SUID rates, but the variation decreased after adjusting for covariates including known risk factors for SUID. After adjustment, nine states demonstrated significantly higher or lower SUID mortality than the national average. Geographic contribution to SUID risk in terms of latitude and longitude were also attenuated after adjustment for covariates.

CONCLUSION

Understanding why some states have lower SUID rates may enhance SUID prevention strategies.

Birth outcomes in a Swedish population of women reporting a history of violence including domestic violence during pregnancy: a longitudinal cohort study

Background

Victimisation of women is encountered in all countries across the world, it damages the mental and physical health of women. During pregnancy and the postpartum period, women are at a greater risk of experiencing violence from an intimate partner. The aim of this study was to explore childbirth outcomes in a Swedish population of women reporting a history of violence including domestic violence during pregnancy.

Methods

A longitudinal cohort design was used. In total, 1939 pregnant women ≥18 years were recruited to answer two questionnaires, both questionnaires were administered in the early and late stages of their pregnancy. The available dataset included birth records of 1694 mothers who gave birth between June 2012 and April 2014. Statistical analyses included descriptive statistics, T-test and bivariate logistic regression.

Results

Of 1694 mothers 38.7% (n = 656) reported a history of violence and 2% (n = 34) also experienced domestic violence during pregnancy. Women who were single, living apart from their partner, unemployed, smoked and faced financial distress were at a higher risk of experiencing violence (p = 0.001). They also had significant low scores on the SOC-scale and high EDS-scores ≥13 (p = 0.001) when compared to women without a history of violence (p = 0.001). Having a history of violence increased the woman’s risk of undergoing a caesarean section (OR 1.33, 95% CI 1.02–1.70). A history of emotional abuse also significantly increased the risk of having a caesarean section irrespective of whether it was a planned or an emergency caesarean section (OR 1.50, 95% CI 1.09–2.06). Infants born to a mother who reported a history of violence, were at significant risk of being born premature < 37 weeks of gestation compared to infants born by mothers with no history of violence (p = 0,049).

Conclusions

A history of violence and/or exclusively a history of emotional abuse has a negative impact on childbirth outcomes including caesarean section and premature birth. Therefore, early identification of a history of or ongoing violence is crucial to provide women with extra support which may have positive impact on her birth outcomes.

Urban-Rural Infant Mortality Disparities by Race and Ethnicity and Cause of Death

INTRODUCTION

Infant mortality rates are higher in nonmetropolitan areas versus large metropolitan areas. Variation by race/ethnicity and cause of death has not been assessed. Urban-rural infant mortality rate differences were quantified by race/ethnicity and cause of death.

METHODS

National Vital Statistics System linked birth/infant death data (2014-2016) were analyzed in 2019 by 3 urban-rural county classifications: large metropolitan, medium/small metropolitan, and nonmetropolitan. Excess infant mortality rates (rate differences) by urban-rural classification were calculated relative to large metropolitan areas overall and for each racial/ethnic group. The number of excess deaths, population attributable fraction, and proportion of excess deaths attributable to underlying causes of death was calculated.

RESULTS

Nonmetropolitan areas had the highest excess infant mortality rate overall. Excess infant mortality rates were substantially lower for Hispanic infants than other races/ethnicities. Overall, 7.4% of infant deaths would be prevented if all areas had the infant mortality rate of large metropolitan areas. With more than half of births occurring outside of large metropolitan areas, the population attributable fraction was highest for American Indian/Alaska Natives (20.3%) and whites, non-Hispanic (14.3%). Excess infant mortality rates in both nonmetropolitan and medium/small metropolitan areas were primarily attributable to sudden unexpected infant deaths (42.3% and 31.9%) and congenital anomalies (30.1% and 26.8%). This pattern was consistent for all racial/ethnic groups except black, non-Hispanic infants, for whom preterm-related and sudden unexpected infant deaths accounted for the largest share of excess infant mortality rates.

CONCLUSIONS

Infant mortality increases with rurality, and excess infant mortality rates are predominantly attributable to sudden unexpected infant deaths and congenital anomalies, with differences by race/ethnicity regarding magnitude and cause of death.

Distinct Populations of Sudden Unexpected Infant Death Based on Age

OBJECTIVES

In most recent studies, authors combine all cases of sudden infant death syndrome, other deaths from ill-defined or unknown causes, and accidental suffocation and strangulation in bed as a single population to analyze sudden unexpected infant death (SUID). Our aim with this study is to determine if there are statistically different subcategories of SUID that are based on the age of death of an infant.

METHODS

In this retrospective, cross-sectional analysis, we analyzed the Centers for Disease Control and Prevention Birth Cohort Linked Birth/Infant Death Data Set (2003-2013: 41 125 233 births and 37 624 SUIDs). Logistic regression models were developed to identify subpopulations of SUID cases by age of death, and we subsequently analyzed the effects of a set of covariates on each group.

RESULTS

Two groups were identified: sudden unexpected early neonatal deaths (SUENDs; days 0-6) and postperinatal SUIDs (days 7-364). These groups significantly differed in the distributions of assigned International Classification of Diseases, 10th Revision code, live birth order, marital status, age of mother, birth weight, and gestational length compared to postperinatal SUIDs (days 7-364). Maternal smoking during pregnancy was not a significant risk factor for deaths that occurred in the first 48 hours.

CONCLUSIONS

SUEND should be considered as a discrete entity from postperinatal SUID in future studies. These data could help improve the epidemiological understanding of SUEND and SUID and provide clues to a mechanistic understanding underlying the causes of death.

Evaluation of the presence and distribution of leptomeningeal inflammation in SIDS/SUDI cases and comparison with a hospital-based cohort

INTRODUCTION

Prior research demonstrates that leptomeninges of infants and late-term fetuses derived from a non-traumatic, hospital-based cohort contain a surprisingly large number of inflammatory cells and stainable iron. These were present irrespective of the findings from the general autopsy, the neuropathologic examination, and the mode of delivery.

MATERIALS AND METHODS

We applied a similar methodology to a sudden infant death syndrome/sudden unexpected death in infancy (SIDS/SUDI) cohort. Forty-two SIDS/SUDI cases autopsied between 2006 and 2014 by the San Diego County Medical Examiner's Office were identified. An interpretable amount of leptomeninges from at least two areas of the brain (cerebral cortex, brain stem, cerebellum) were present in each case. Immunoperoxidase (IPOX) staining with CD45 and CD68 was performed and Perl's method was used to detect the presence of iron. The number of immunoreactive cells per IPOX stain within the leptomeninges in each slide was manually tabulated and the density subsequently quantified. The presence or absence of stainable iron was noted.

RESULTS

This cohort represented 22 males and 20 females ranging in age from 2 to 311 days, with relatively evenly divided modes of delivery. The examined brain sections included 32 of the cerebral cortex, 18 of the brain stem, and 36 of the cerebellum. The lengths of the examined leptomeninges ranged from 2 to 40 mm. The ranges of the number of cells per millimeter, and the standard deviations of the means were wide and varied. Overall, there was no significant difference in the number of CD45 or CD68 immunoreactive cells/millimeter between the three brain sites. Comparing this cohort to a subpopulation of hospitalized infants in our prior study, there were no significant differences between the density of inflammatory cells in the sections from the cerebral cortex and brain stem. There were differences in the CD68 densities, particularly in the cerebellar sections which may be attributable to methodological differences. Iron was identified in only a single section in this cohort but was present in most of the cases in the hospital-based cohort.

CONCLUSION

This study further elucidates the relevance of the presence of inflammatory cells and iron in the leptomeninges. Whether in a hospital-based or more forensically relevant population, the presence of inflammatory cells in the leptomeninges (even in great abundance) is common.

Sudden Unexpected Infant Death: Review and Analysis of Adherence to Recommendations

Introduction Sudden Unexpected Infant Death (SUID) is a term that englobes the sudden and unexpected death of an infant less than 12 months, which can be explained by organic or traumatic causes, or that can't be explained such as cases of Sudden Infant Death Syndrome (SIDS). Although many risk factors have been associated with this syndrome, one of the most widely associated and studied are incorrect sleeping techniques and practices. In 2016, the American Academy of Pediatrics (AAP) updated their safe-sleeping guidelines and sleeping environment recommendations and strategies to prevent SIDS. Methods We conducted a cross-sectional study to analyze the sleeping environments in infants that attended both the inpatient and outpatient services at a public pediatric hospital in Mexico City. A 6-item questionnaire was applied to the parent or guardian to assess the sleeping habits of infants in their homes. Results A total of 184 infants were included in the study, with a mean age of 5.87 months. Overall, the number of parents that follow safe sleeping practices was very low, with no parents following all the AAP recommendations, and over 10% not following any. Although there is uncertainty about the pathogenesis of this syndrome, the focus has shifted to prevention, especially regarding the modifiable risk factors. Conclusions It was demonstrated that our population did not know about the proper and safe sleeping techniques. In the nearby future, our goal is for health authorities in our country to implement a strategy to make the AAP recommendations part of government health campaigns.

Inconsistent classification of unexplained sudden deaths in infants and children hinders surveillance, prevention and research: recommendations from The 3rd International Congress on Sudden Infant and Child Death

This report details the proceedings and conclusions from the 3rd International Congress on Unexplained Deaths in Infants and Children, held November 26–27, 2018 at the Radcliffe Institute at Harvard University. The Congress was motivated by the increasing rejection of the diagnosis Sudden Infant Death Syndrome (SIDS) in the medical examiner community, leading to falsely depressed reported SIDS rates and undermining the validity and reliability of the diagnosis, which remains a leading cause of infant and child mortality. We describe the diagnostic shift away from SIDS and the practical issues contributing to it. The Congress was attended by major figures and opinion leaders in this area from countries significantly engaged in this problem. Four categories (International Classification of Diseases (ICD)-11 categories of MH11, MH12, MH14, PB00-PB0Z) were recommended for classification, and explicit definitions and guidance were provided for death certifiers. SIDS was reframed as unexplained sudden death in infancy or SIDS/MH11 to emphasize that either term signifies the lack of explanation following a rigorous investigation. A distinct category for children over the age of 1 was recommended (MH12). Definitions and exclusions were provided for the alternative categories of accidental asphyxia and undetermined. As recommended, unexplained sudden death in infancy or SIDS on a death certificate will code a unique, trackable entity, accurately reflecting the inability to determine a definitive explanation, while satisfying surveillance needs and reliable identification for research efforts. The conclusions will be submitted to the World Health Organization for inclusion in the upcoming ICD-11.

Modifiable sleep-related risk factors in infant deaths in Cook County, Illinois

Background

Each year, approximately 3500 infants in the United States die from sleep-related deaths. The number of sleep-related infant deaths has decreased overall since the 1990s, but disparities in sleep-related deaths persist among different populations. The purpose of this study was to determine the most common risk factors and locations in Cook County, Illinois for sleep-related deaths in infants under 6 months of age.

Methods

We conducted a retrospective study among infants less than 6 months of age who died in Cook County, Illinois in 2015 and 2016, in which the manner of death was of undetermined intent with at least one modifiable sleeping risk factor present, as reported by the medical examiner. Data were obtained from the Illinois Violent Death Reporting System (IVDRS), a state-based, anonymous, surveillance system. County trends and circumstances of the deaths were also evaluated. Frequencies, percentages, and Chi-square analysis were used to describe and characterize these deaths.

Results

In Cook County in 2015 and 2016, 116 infants less than 6 months of age died where the manner of death was classified as undetermined intent. The median age of death was 2 months. Of these deaths, 63 (54.3%) of the infants were boys. African-American and Hispanic infants comprised 71 (65.7%) and 23 (21.3%) of the deaths, respectively. In 84 (72.4%) of the cases, at least one known sleeping risk factor was present and 56 (66.7%) of the infants who died with a known sleeping risk factor were co-sleeping. Notably, 33 (29.7%) of the deaths in Cook County were clustered within six zip codes.

Conclusions

The majority of infants who died unexpectedly in Cook County in 2015 and 2016 did so in the presence of sleeping risk factors, with co-sleeping being the most common. African-American infants, infants under 2 months of age, and several geographical areas within Chicago appear to be at increased risk. Interventions to target these preventable causes in the populations at increased risk should be instituted to prevent future deaths.

Policy-induced selection bias in pharmacoepidemiology: The example of coverage for Alzheimer's medications in British Columbia

PURPOSES

To assess the impact of a government-sponsored reimbursement policy for cholinesterase inhibitors (ChEIs) on trends in physician visits with a diagnosis of Alzheimer's disease (AD).

METHODS

Longitudinal population-based study using interrupted time series methods. British Columbia outpatient claims data for individuals aged 65 and older were used to compute monthly AD visit rates and examine the impact of the ChEI reimbursement policy on the coding of AD. We examined trends in the number of patients with AD visits, the number of AD visits per patient, and visits with "competing" diagnoses (mental, neurological, and cerebrovascular disorders and accidental falls). Finally, we described demographic and clinical features of diagnosed patients.

RESULTS

We analyzed 1.9 million AD visits. Faster growth in recorded AD visits was observed after the policy was implemented, from monthly growth of 7.5 visits per 100 000 person-months before the policy (95% confidence interval [CI], 6.1-8.9) to monthly growth of 16.5 per 100 000 person-months after the policy (95% CI, 14.8-18.3). After the implementation of the policy, we observed increased growth in the number of patients with recorded AD visits and the number of AD visits per patient, as well as a shift in diagnoses away from mental diseases and accidental falls to AD (diagnosis substitution).

CONCLUSIONS

British Columbia's reimbursement policy for ChEIs was associated with a significant acceleration in Alzheimer's visits. Evaluations of health services utilization and clinical outcomes following drug policy changes need to consider policy-induced influences on the reliability of the data used in the analysis.

Accidental Infant Suffocation and Strangulation in Bed: Disparities and Opportunities

Objectives (a) Update previous descriptions of trends in ASSB; (b) determine if factors previously associated with ASSB are replicated by updated data; and (c) generate new hypotheses about the occurrence of ASSB and racial inequalities in ASSB mortality. Methods National Center for Health Statistics files (International Classification of Diseases, Tenth Edition) Code W75 to describe race-ethnicity-specific ASSB occurrence. Results (a) ASSB mortality continues to increase significantly; for 1999-2016, 4.4-fold for NHB girls (45.8 per 100,000 in 2016), 3.5-fold for NHB boys (53.8), 2.7-fold for NHW girls (15.8) and 4.0-fold for NHW boys (25.9); (b) F actors previously associated with ASSB (unmarried mothers and mothers with low educational attainment, low infant birth weight, low gestational age, lack of prenatal care, male infant, multiple birth, high birth order) continue to be associated with both overall ASSB and inequalities adversely affecting NHB; (c) (1) geographic differences and similarities in ASSB occurrence support hypotheses related to positive deviance; (2) lower ASSB mortality for births attended by midwives as contrasted to physicians generate hypotheses related to both medical infrastructure and maternal engagement; (3) high rates of ASSB among infants born to teenage mothers generate hypotheses related to the possibility that poor maternal health may be a barrier to ASSB prevention based on education, culture and tradition. Conclusions for Practice These descriptive data may generate new hypotheses and targets for interventions for reducing both ASSB mortality and racial inequalities. Analytic epidemiologic studies designed a priori to do so are required to address these hypotheses.

Maternal Smoking Before and During Pregnancy and the Risk of Sudden Unexpected Infant Death

OBJECTIVES

Maternal smoking during pregnancy is an established risk factor for sudden unexpected infant death (SUID). Here, we aim to investigate the effects of maternal prepregnancy smoking, reduction during pregnancy, and smoking during pregnancy on SUID rates.

METHODS

We analyzed the Centers for Disease Control and Prevention Birth Cohort Linked Birth/Infant Death Data Set (2007-2011: 20 685 463 births and 19 127 SUIDs). SUID was defined as deaths at <1 year of age with International Classification of Diseases, 10th Revision codes R95 (sudden infant death syndrome), R99 (ill-defined or unknown cause), or W75 (accidental suffocation or strangulation in bed).

RESULTS

SUID risk more than doubled (adjusted odds ratio [aOR] = 2.44; 95% confidence interval [CI] 2.31-2.57) with any maternal smoking during pregnancy and increased twofold between no smoking and smoking 1 cigarette daily throughout pregnancy. For 1 to 20 cigarettes per day, the probability of SUID increased linearly, with each additional cigarette smoked per day increasing the odds by 0.07 from 1 to 20 cigarettes; beyond 20 cigarettes, the relationship plateaued. Mothers who quit or reduced their smoking decreased their odds compared with those who continued smoking (reduced: aOR = 0.88, 95% CI 0.79-0.98; quit: aOR = 0.77, 95% CI 0.67-0.87). If we assume causality, 22% of SUIDs in the United States can be directly attributed to maternal smoking during pregnancy.

CONCLUSIONS

These data support the need for smoking cessation before pregnancy. If no women smoked in pregnancy, SUID rates in the United States could be reduced substantially.

Racial differences within subsets of Sudden Unexpected Infant Death (SUID) with an emphasis on asphyxia

OBJECTIVE

Sudden Unexpected Infant Deaths (SUID) is defined as a combination of Sudden Infant Death Syndrome (SIDS), Unknown Cause of Death (UCD) and Accidental Suffocation and Strangulation in Bed (ASSB). Overall rates from 2000 to 2015 have been trending down. Racial differences in occurrence are seen.

STUDY DESIGN AND SETTING

Using the CDC Wonder Database, the total rates of SUID and its subsets were examined.

RESULTS

Non-Caucasian infant death rates for the total SUID group, and the SIDS component, are trending downward significantly faster than for Caucasians. UCD trends in rates show an apparent small, non-significant, decline for non-Caucasians, and are unchanged for Caucasians. ASSB rates are trending upward slightly more rapidly (not significantly) for non-Caucasians than Caucasians.

CONCLUSION

The trend showing ASSB trending upward more in non-Caucasians than Caucasians may suggest: 1) A racial difference that certifiers are more willing to certify SIDS than ASSB in Caucasians, and/or 2) Certifiers are biased towards certifying more ASSB than SIDS in non-Caucasians, and/or 3) Asphyxia risks may be increasing more in non-Caucasian SUIDs. Option #1 would require educational efforts to recognize the asphyxia risks in Caucasians. Option #2 would require documentation of racial bias in infant death certification followed by efforts to reduce the bias. Option #3 would require focused targeting of non-Caucasian populations to reduce asphyxia risks. Potentially all three scenarios could co-exist.

Infant and Youth Mortality Trends by Race/Ethnicity and Cause of Death in the United States

IMPORTANCE

The United States has higher infant and youth mortality rates than other high-income countries, with striking disparities by racial/ethnic group. Understanding changing trends by age and race/ethnicity for leading causes of death is imperative for focused intervention.

OBJECTIVE

To estimate trends in US infant and youth mortality rates from 1999 to 2015 by age group and race/ethnicity, identify leading causes of death, and compare mortality rates with Canada and England/Wales.

DESIGN, SETTING, AND PARTICIPANTS

This descriptive study analyzed death certificate data from the US National Center for Health Statistics, Statistics Canada, and the UK Office of National Statistics for all deaths among individuals younger than 25 years. The study took place from January 1, 1999, to December 31, 2015, and analyses started in September 2017.

EXPOSURES

Race/ethnicity.

MAIN OUTCOMES AND MEASURES

Average annual percent changes in mortality rates from 1999 to 2015 and absolute rate change between 1999 to 2002 and 2012 to 2015 for each age group, race/ethnicity, and cause of death.

RESULTS

Among individuals from birth to age 24 years, 1 169 537 deaths occurred in the United States, 80 540 in Canada, and 121 183 in England/Wales from 1999 to 2015. In the United States, 64% of deaths occurred in male individuals and 52.6% occurred in white individuals (25.1% deaths occurred in black individuals and 17.9% in Latino individuals). All-cause mortality declined for all age groups (infants younger than 1 year [38.5% of deaths], children aged 1-9 years [10.6%], early adolescents aged 10-14 years [5%], late adolescents aged 15-19 years [17.7%], and young adults aged 20-24 years [28.1%]) in the United States, Canada, and England/Wales from 1999 to 2015. However, rates were highest in the United States. Within the United States, annual declines in all-cause mortality rates occurred among all age groups of black, Latino, and white individuals, except for white individuals aged 20 to 24 years, whose rates remained stable. Mortality rates declined across most major causes of death from 1999 to 2002 and 2012 to 2015, with notable declines observed for sudden infant death syndrome, unintentional injury death, and homicides. Among infants, unintentional suffocation and strangulation in bed increased (difference between 2012-2015 and 1999-2002 range, 6.11-29.03 per 100 000). Further, suicide rates among Latino and white individuals aged 10 to 24 years (range, 0.21-2.63 per 100 000) and black individuals aged 10 to 19 years (range, 0.10-0.45 per 100 000) increased, as did unintentional injury deaths in white young adults (0.79 per 100 000). The rise in unintentional injury deaths is attributed to increases in drug poisonings and was also observed in black and Latino young adults.

CONCLUSIONS AND RELEVANCE

Mortality rates in the United States have generally declined for infants and youths from 1999 to 2015 owing to reductions in sudden infant death syndrome, unintentional injury death, and homicides. However, US mortality rates remain higher than Canada and England/Wales, with particularly elevated rates among black and American Indian/Alaskan Native youth. Further, there is a concerning increase in suicide and drug poisoning death rates among US adolescents and young adults.

Characteristics of Infant Deaths during Sleep While Under Nonparental Supervision

OBJECTIVE

To compare risk factors for infant sleep-related deaths under the supervision of parents and nonparents.

STUDY DESIGN

We conducted a secondary analysis of sleep-related infant deaths from 2004 to 2014 in the National Center for Fatality Review and Prevention Child Death Review Case Reporting System. The main exposure was supervisor at time of death. Primary outcomes included sleep position, location, and objects in the environment. Risk factors for parental vs nonparental supervisor were compared using χ² and multivariable logistic regression models. Risk factors associated with different nonparental supervisors were analyzed using χ².

RESULTS

Of the 10 490 deaths, 1375 (13.1%) occurred under nonparental supervision. Infants who died under nonparental supervision had higher adjusted odds of dying outside the home (OR 12.87, 95% CI 11.31-14.65), being placed prone (OR 1.61, 95% CI 1.39-1.86) or on their side (OR 1.35, 95% CI 1.12-1.62), or being found prone (OR 1.74, 95% CI 1.50-2.02). Among infants who died under nonparental supervision, those supervised by relatives or friends were more often placed on an adult bed or couch for sleep and bed sharing (P < .0001), and to have objects in the sleep environment (P = .01).

CONCLUSIONS

Infants who died of sleep-related causes under nonparental supervision were more likely to have been placed nonsupine. Among nonparental supervisors, relatives and friends were more likely to use unsafe sleep environments, such as locations other than a crib or bassinet and bed sharing. Pediatricians should educate parents that all caregivers must always follow safe sleep practices.

Trends in the Incidence of Sudden Unexpected Infant Death in the Newborn: 1995-2014

OBJECTIVE

To evaluate the epidemiology of sudden unexpected infant death (SUID) over a 20-year period in the US, to assess the potential frequency of sudden unexpected postnatal collapse in the early days of life, and to determine if SUID rates in the neonatal period (0-27 days) have changed in parallel with rates in the postneonatal periods, including the percentages attributed to codes that include accidental suffocation.

STUDY DESIGN

Data from the US Centers for Disease Control and Prevention Linked Birth/Infant Death Records for 1995-2014 were analyzed for the first hour, day, week, and month of life. A comparison of neonatal and postneonatal data related to SUID, including accidental suffocation, was carried out.

RESULTS

Death records for 1995-2014 indicate that, although SUID rates in the postneonatal period have declined subsequent to the 1992 American Academy of Pediatrics sleep position policy change, newborn SUIDs have failed to decrease, and the percentage of SUIDs attributed to unsafe sleep conditions has increased significantly in both periods; 29.2% of the neonatal cases occurred within the first 6 days of life.

CONCLUSIONS

The frequency of SUIDs during the neonatal period warrants ongoing attention to all circumstances contributing to this category of deaths. The development of a standardized definition of sudden unexpected postnatal collapse and a national registry of these events is recommended. Ongoing research on the effects of early neonatal practices on postneonatal SUID should also be encouraged.

National and State Trends in Sudden Unexpected Infant Death: 1990-2015

BACKGROUND

Sharp declines in sudden unexpected infant death (SUID) in the 1990s and a diagnostic shift from sudden infant death syndrome (SIDS) to unknown cause and accidental suffocation and strangulation in bed (ASSB) in 1999-2001 have been documented. We examined trends in SUID and SIDS, unknown cause, and ASSB from 1990 to 2015 and compared state-specific SUID rates to identify significant trends that may be used to inform SUID prevention efforts.

METHODS

We used data from US mortality files to evaluate national and state-specific SUID rates (deaths per 100 000 live births) for 1990-2015. SUID included infants with an underlying cause of death, SIDS, unknown cause, or ASSB. To examine overall US rates for SUID and SUID subtypes, we calculated the percent change by fitting Poisson regression models. We report state differences in SUID and compared state-specific rates from 2000-2002 to 2013-2015 by calculating the percent change.

RESULTS

SUID rates declined from 154.6 per 100 000 live births in 1990 to 92.4 in 2015, declining 44.6% from 1990 to 1998 and 7% from 1999 to 2015. From 1999 to 2015, SIDS rates decreased 35.8%, ASSB rates increased 183.8%, and there was no significant change in unknown cause rates. SUID trends among states varied widely from 41.5 to 184.3 in 2000-2002 and from 33.2 to 202.2 in 2013-2015.

CONCLUSIONS

Reductions in SUID rates since 1999 have been minimal, and wide variations in state-specific rates remain. States with significant declines in SUID rates might have SUID risk-reduction programs that could serve as models for other states.

Excess mortality in children born to opioid-addicted parents: A national register study in Taiwan

BACKGROUND

Young offspring of individuals with opioid use disorders have great exposure to a wide array of social disadvantages and stressors. This study aimed to investigate excess mortality before the age of six and predictors of premature death in children born to opioid-involved parents.

METHODS

A total of 3210 children born between 2004 and 2009 to parents with opioid use disorders (roughly a quarter of whom were born after parental methadone treatment enrollment) were identified in Taiwan. Information concerning sociodemographic characteristics, history of medical condition, and survival status was obtained through data linkage with the National Health Insurance Database and death registration. The age-, birth year-, and sex-adjusted standardized mortality ratios (SMRs) and survival analyses were used to assess risk estimates and evaluate predictors.

RESULTS

The overall SMR for children with opioid-involved parents was 2.31 (95% confidence interval [CI] = 1.68-3.10), with the estimate reaching 4.23 (95% CI = 2.37-6.97) when the causes of death were unnatural (e.g., injury and accident). The most salient predictors of premature death were low birth weight and paternal opioid problem severity, which increased risk of premature death 2.5--5.2-fold (all P < 0.05). Being born after parents enrolled in methadone treatment was slightly associated with a reduced risk of death in those mothered by opioid users (adjusted hazard ratio = 0.30).

CONCLUSION

The elevated risk of premature death in the offspring of opioid-addicted parents suggests the need to prioritize resource allocation to safeguard this marginalized and vulnerable segment of the pediatric population.

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.

Sudden Unexpected Infant Death Certification in New York City: Intra-Agency Guideline Compliance and Variables that May Influence Death Certification

INTRODUCTION

Differences in certification of similar sudden infant deaths exists among forensic pathologists. This study sought to measure adherence to intra-agency guidelines for infant death certification in one jurisdiction and describe variables that may be associated with the differentiation of sudden infant death syndrome (SIDS), asphyxia, and undetermined death certifications.

METHODS

A retrospective study of deaths at the New York City Office of Chief Medical Examiner identified 427 sudden infant deaths with investigation and autopsy whose cause of death was ruled SIDS, asphyxia, or undetermined. Cases were reviewed for number and types of risk factors for asphyxia, demonstrable evidence of asphyxia, potential competing causes of death, and a doll reenactment. Descriptive and statistical analysis was performed.

RESULTS

Of 427 deaths, the causes of 100 deaths (23.4%) were ruled asphyxia; 43 (10.0%) SIDS; and 284 (66.5%) undetermined. Forensic pathologists conformed to agency guidelines in 406 deaths (95.1%). Three or more risk factors for asphyxia were found in 328 deaths (76.8%). Demonstrable evidence of asphyxia (40.7%) was most associated with a certification of asphyxia. A potential competing cause of death (20%) was most associated with undetermined. A doll reenactment had little association with certification type.

DISCUSSION

Guidelines in one agency were effective at limiting incorrect SIDS diagnoses. The interpretation of risk factors can be subjective. Diagnostic overlap occurred in deaths certified differently as SIDS, asphyxia, and undetermined, despite similar findings. Elimination of SIDS as a certification option and better guidelines that help differentiate asphyxia and undetermined deaths are recommended for improved infant death certification.