Factors associated with age of death in sudden unexpected infant death

Known pathogenic gene variants and new candidates detected in sudden unexpected infant death using whole genome sequencing

The purpose of this study is to gain insights into potential genetic factors contributing to the infant's vulnerability to Sudden Unexpected Infant Death (SUID). Whole Genome Sequencing (WGS) was performed on 144 infants that succumbed to SUID, and 573 healthy adults. Variants were filtered by gnomAD allele frequencies and predictions of functional consequences. Variants of interest were identified in 88 genes, in 64.6% of our cohort. Seventy-three of these have been previously associated with SIDS/SUID/SUDP. Forty-three can be characterized as cardiac genes and are related to cardiomyopathies, arrhythmias, and other conditions. Variants in 22 genes were associated with neurologic functions. Variants were also found in 13 genes reported to be pathogenic for various systemic disorders and in two genes associated with immunological function. Variants in eight genes are implicated in the response to hypoxia and the regulation of reactive oxygen species (ROS) and have not been previously described in SIDS/SUID/SUDP. Seventy-two infants met the triple risk hypothesis criteria. Our study confirms and further expands the list of genetic variants associated with SUID. The abundance of genes associated with heart disease and the discovery of variants associated with the redox metabolism have important mechanistic implications for the pathophysiology of SUID.

Promoting Safe Sleep: The Role of Doulas in Black Communities

BACKGROUND

Accidental suffocation and strangulation in bed continues to be a critical issue in Black communities, despite the widespread initiatives to promote safe sleep. Doulas are in an ideal position to promote safe sleep, particularly in hard-to-reach communities that are more distrusting of conventional medical providers. Little is known about their practices and perspectives for putting infants down to rest. This study informs this gap in the literature.

PURPOSE

The purpose of this study was to explore doulas' perspectives and practices in the field of putting infants down to sleep. The researchers aimed to determine whether Black caregivers that work with doulas are likely to encounter safe sleep education.

METHODS

The researchers used a descriptive approach to inquiry. They conducted three focus groups with a total of 17 Black doulas. The researchers independently and critically reviewed the transcriptions and observation notes from each group to identify codes. They then triangulated the results using Artificial Intelligence-driven tools.

FINDINGS

The study found four themes: (1) Individualized Services, (2) Cultural Sensitivity, (3) Negotiating Safety, and (4) Safe Sleep Education.

CONCLUSIONS

The study concluded doulas have a commitment to promoting safe sleep. The researchers found that doulas engage in practices that help caregivers to integrate safe sleep practices into their lifestyle and to adapt them to meet their needs. The researchers also documented a desire for more information and instruction on safe sleep among practicing doulas.

Risk factors for unexpected infant death among very premature infants in France

BACKGROUND

Prematurity is one of the risk factors for sudden unexpected infant death (SUID), a phenomenon that remains poorly explained.

MATERIALS AND METHODS

The analysis of specific factors associated with SUID among very premature infants (VPI) was performed through a retrospective review of data collected in the French SUID registry from May 2015 to December 2018. The factors associated with SUID among VPI were compared with those observed among full-term infants (FTI). Results are expressed as means (standard deviation [SD]) or medians (interquartile range [IQR)].

RESULTS

During the study period, 719 cases of SUID were included in the registry, 36 (incidence: 0.60 ‰) of which involved VPI (gestational age: 29.2 [2] weeks, 1157 [364]) g] and 313 (0.18 ‰) involved FTI (gestational age: 40 [0.8] weeks, 3298 [452] g). The infants' postnatal age at the time of death was similar in the two groups: 15.5 (12.2-21.8) vs. 14.5 (7.1-23.4) weeks. We observed low breastfeeding rates and a high proportion of fathers with no occupation or unemployment status among the VPI compared to the FTI group (31% vs. 55 %, p = 0.01 and 32% vs. 13 %, p = 0.05, respectively). Among the VPI, only 52 % were in supine position, and 29 % were lying prone at the time of the SUID (compared to 63 % and 17 %, respectively, in the FTI group).

CONCLUSION

This study confirms prematurity as a risk factor for SUID with no difference in the SUID-specific risk factors studied except for breastfeeding and socioeconomic status of the fathers. VPI and FTI died at similar chronological ages with a high proportion of infants dying in prone position. These results argue for reinforcement of prevention strategies in cases of prematurity.

Altered 5-HT2A/C receptor binding in the medulla oblongata in the sudden infant death syndrome (SIDS): Part I. Tissue-based evidence for serotonin receptor signaling abnormalities in cardiorespiratory- and arousal-related circuits

The sudden infant death syndrome (SIDS), the leading cause of postneonatal infant mortality in the United States, is typically associated with a sleep period. Previously, we showed evidence of serotonergic abnormalities in the medulla (e.g. altered serotonin (5-HT)1A receptor binding), in SIDS cases. In rodents, 5-HT2A/C receptor signaling contributes to arousal and autoresuscitation, protecting brain oxygen status during sleep. Nonetheless, the role of 5-HT2A/C receptors in the pathophysiology of SIDS is unclear. We hypothesize that in SIDS, 5-HT2A/C receptor binding is altered in medullary nuclei that are key for arousal and autoresuscitation. Here, we report altered 5-HT2A/C binding in several key medullary nuclei in SIDS cases (n = 58) compared to controls (n = 12). In some nuclei the reduced 5-HT2A/C and 5-HT1A binding overlapped, suggesting abnormal 5-HT receptor interactions. The data presented here (Part 1) suggest that a subset of SIDS is due in part to abnormal 5-HT2A/C and 5-HT1A signaling across multiple medullary nuclei vital for arousal and autoresuscitation. In Part II to follow, we highlight 8 medullary subnetworks with altered 5-HT receptor binding in SIDS. We propose the existence of an integrative brainstem network that fails to facilitate arousal and/or autoresuscitation in SIDS cases.

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.

Sudden unexpected infant death risk profiles in the first month of life

BACKGROUND

Limited improvement in current SUID rates requires further identification of its characteristics, including age-specific risk patterns.

OBJECTIVE

Compare SUID risk factors in the first week versus the remainder in the first month of life.

DESIGN/METHODS

We compared maternal and infant data from New Jersey databases for SUID from 2000 to 2015 in infants ≥ 34 weeks GA in the two groups.

RESULTS

In the period studied, 123 died in the first 27 days, 24 before seven. Deaths in the first week had a higher percentage of mothers with post-High School education (OR 3.50, CI: 1.38-8.87) and a primary Cesarean section delivery (OR 4.0, CI: 1.39-11.49), and a smaller percentage with inadequate prenatal care (OR 0.36, CI: 0.14, 0.94). A smaller percentage of first-week deaths had mothers who smoked during pregnancy or identified as Black, non-Hispanic, but these findings did not reach significance (p < .08 and p < .09, respectively).

CONCLUSIONS

SUID in the first week and the first month of life is rare. However, despite a limited sample size, data suggest that even within the first month of life, there are differences in risk patterns for SUID based on age at death. Age-specific profiles may lead to new hypotheses regarding causality and more refined risk-reduction guidelines and warrant further study.

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.