Sudden infant death syndrome: risk factors for infants found face down differ from other SIDS cases

The socio-economic status of families experiencing the sudden unexpected death of an infant - Is it possibly related to a higher rate of non-natural deaths among them

Low socio-economic status is recognized as one of the risk factors for SIDS. In this study we have pointed out the similarities between families that have SIDS cases and families in which infant non-accidental injury has been proven, as well as the differences between them and the general population. This study was conducted in Montenegro, comparing 30 cases of SIDS with 25 cases of known infanticides and with a control group (60 cases) consisting of live newborns and their mothers from the general population, randomly selected from hospital-born newborns without exclusion criteria. We combined and compared the infant characteristics and mother characteristics between the above cases. There were significant similarities between the SIDS group and the infanticide group in terms of the following characteristics: the education level of the mothers (p = 0.086); maternal employment (p = 0.278); and place of residence (p = 0.269); while there were differences between the two groups regarding hospital birth (p = 0.027) and marital status (p = 0.011). The SIDS and infanticide groups, combined, had higher incidences of: out-of-hospital deliveries (p < 0.001); uneducated mothers (p < 0.001); unemployed mothers (p < 0.001); low socio-economic status (p < 0.001); and cases outside of marriage (p < 0.001), compared to the control groups. This study indicated a possible higher incidence of non-natural death among SIDS cases, as reflected by low socio-economic status and linked attributes, which is explained by their similarities with the infanticide groups and differences with the control groups.

Simultaneous Sudden Infant Death Syndrome: Case Report

Simultaneous sudden infant death syndrome (SSIDS) is death of both twins within 24 hours which is compatible with the sudden infant death syndrome criteria and death is independent of each other. A pair of twin babies, approximately two months old, was found dead in the supine position in bed by their mother. After scene, autopsy, toxicological and histopathological investigations, specific cause of death could not be found. There were 41 pairs of twin babies with SSIDS reported in the literature between 1900 and 1998. This is the second case report from Turkey.

Hypoxia and hypercapnia inhibit hypothalamic orexin neurons in rats

Evidence of impaired function of orexin neurons has been found in individuals with cardiorespiratory disorders, such as obstructive sleep apnea (OSA) and sudden infant death syndrome (SIDS), but the mechanisms responsible are unknown. Individuals with OSA and SIDS experience repetitive breathing cessations and/or rebreathing of expired air, resulting in hypoxia/hypercapnia (H/H). In this study, we examined the responses of fluorescently identified rat orexin neurons in the lateral hypothalamus to acute H/H to test if and how these neurons alter their activity and function during this challenge. Experiments were conducted in an in vitro slice preparation using voltage-clamp and current-clamp configurations. H/H (10 min) induced hyperpolarization, accompanied by rapid depression, and finally, cessation of firing activity in orexin neurons. Hypoxia alone had similar but less potent effects. H/H did not alter the frequency of inhibitory glycinergic postsynaptic currents. The frequency of GABAergic currents was diminished but only at 8-10 min of H/H. In contrast, the frequency of excitatory glutamatergic postsynaptic events was diminished as early as 2-4 min of H/H. In the presence of glutamatergic receptor blockers, the inhibitory effects of H/H on the firing activity and membrane potential of orexin neurons persisted but to a lesser extent. In conclusion, both direct alteration of postsynaptic membrane properties and diminished glutamatergic neurotransmission likely contribute to the inhibition of orexin neurons by H/H. These mechanisms could be responsible for the decreased function of orexin in individuals at risk for OSA and SIDS.

Parent-child bed-sharing: The good, the bad, and the burden of evidence

The practice of parent and child sharing a sleeping surface, or 'bed-sharing', is one of the most controversial topics in parenting research. The lay literature has popularized and polarized this debate, offering on one hand claims of dangers, and on the other, of benefits - both physical and psychological - associated with bed-sharing. To address the scientific evidence behind such claims, we systematically reviewed 659 published papers (peer-reviewed, editorial pieces, and commentaries) on the topic of parent-child bed-sharing. Our review offers a narrative walkthrough of the many subdomains of bed-sharing research, including its many correlates (e.g., socioeconomic and cultural factors) and purported risks or outcomes (e.g., sudden infant death syndrome, sleep problems). We found general design limitations and a lack of convincing evidence in the literature, which preclude making strong generalizations. A heat-map based on 98 eligible studies aids the reader to visualize world-wide prevalence in bed-sharing and highlights the need for further research in societies where bed-sharing is the norm. We urge for multiple subfields - anthropology, psychology/psychiatry, and pediatrics - to come together with the aim of understanding infant sleep and how nightly proximity to the parents influences children's social, emotional, and physical development.

Breastfeeding and dummy use have a protective effect on sudden infant death syndrome

We conducted a literature review on the effect of breastfeeding and dummy (pacifier) use on sudden infant death syndrome (SIDS). From 4343 abstracts, we identified 35 relevant studies on breastfeeding and SIDS, 27 on dummy use and SIDS and 59 on dummy use versus breastfeeding.

Conclusion

We found ample evidence that both breastfeeding and dummy use reduce the risk of SIDS. There has been a general reluctance to endorse dummy use in case it has a detrimental effect of breastfeeding. However, recent evidence suggests that dummy use might not be as harmful to breastfeeding as previously believed.

Cumulative effects of repetitive intermittent hypercapnic hypoxia on orexin in the developing piglet hypothalamus

Orexin neuropeptides (OxA and OxB) and their receptors (OX1R and OX2R) are involved in maintenance of sleep and wakefulness, and are regulated by various environmental stimuli. We studied piglets, in the early neonatal period, exposed to 48-min of intermittent hypercapnic hypoxia (IHH; 7% O2/8% CO2) alternating with air. Three groups of 13-14 day-old piglets with IHH exposure of 1-day (1D-IHH) (n=7), 2-days (2D-IHH) (n=7) and 4-days (4D-IHH) (n=8) were compared to controls (exposed only to air, n=8). Immunoreactivity of OxA and OxB was studied in the piglet hypothalamic regions of the dorsomedial hypothalamus (DMH), perifornical area (PeF) and lateral hypothalamic area (LH). Results showed that after 1D- and 2D-IHH, total OxA and OxB expression decreased by 20% (p ≤ 0.005) and 40% (p<0.001), respectively. After 4D-IHH, the decrease in OxA and OxB was 50% (p<0.001). These findings indicate that a chronic IHH exposure induces greater changes in orexin neuropeptide expression than an acute 1-day exposure in the hypothalamus. This may be causally related to the dysregulation of sleep.

Orexin receptors in the developing piglet hypothalamus, and effects of nicotine and intermittent hypercapnic hypoxia exposures

Orexin and its receptors (OxR1 and OxR2) play a significant role in arousal and sleep regulation. Using developing piglets, we aimed to determine the effects of nicotine and Intermittent Hypercapnic Hypoxia (IHH), alone or in combination, on orexin receptor expression in the hypothalamus. Four piglet groups were studied: control (n=14), nicotine (n=14), IHH (n=10) and nic+IHH (n=14). Applying immunohistochemistry for OxR1 and OxR2 expression, eight nuclei/areas of the hypothalamus: dorsal medial nucleus (DMN), arcuate nucleus (ARC), perifornical area (PFA), paraventricular nucleus (PVN), lateral hypothalamic area (LHA), ventral medial nucleus (VMN), supraoptic nucleus, retrochiasmatic part (SONr) and tuberal mammillary nucleus (TMN), were studied. Compared to controls, OxR1 and OxR2 were increased due to exposures, however this was region dependent. Nicotine increased OxR1 in the DMN (P<0.001) and SONr (P=0.036), and OxR2 in the DMN (P<0.001), VMN (P=0.014) and the TMN (P=0.026). IHH increased OxR1 in the DMN, PVN, VMN and SONr (P<0.01 for all), and OxR2 in DMN (P<0.001), PFA (P=0.001), PVN (P=0.004), VMN (P=0.041) and the TMN (P<0.001). The nic+IHH exposure increased OxR1 expression in all nuclei (TMN excluded) however, the changes were not significantly different from IHH alone. For OxR2, the increased expression after nic+IHH was significant compared to IHH in the DMN, ARC and SONr. These results show that nicotine increases orexin receptor expression in a region dependent manner. IHH induced increases were specific to arousal and stress related regions and nic+IHH results suggest that for OxR1, nicotine has no additive effect whereas for OxR2 it does, and is region dependent.

The prevalence of cobedding and SIDS-related child care practices in twins

Sudden unexplained and unexpected death in twins has not been well studied, particularly in relation to the common practice of sleeping twin infants together in the same cot (cobedding). Postal surveys of 109 mothers of twins were undertaken when the infants were 6 weeks, 4 months, and 8 months of age to determine the prevalence of cobedding, infant care practices related to sudden infant death syndrome (SIDS), and the mother's knowledge of SIDS risk factors. SIDS risk factor knowledge was similar to an earlier survey of singletons in 2005. At 6 weeks, 76% of infants usually slept on the back; this changed to 86% at 4 months and 73% at 8 months. At 6 weeks, 52% usually cobedded with their twin all or part of the time. At 4 and 8 months, this had reduced to 31% and 10%, respectively. Side-by-side cobedding configurations were predominant at 6 weeks, with feet-to-feet configurations increasing as the infants grew older. Breastfeeding was reported in 83%, 61% and 31% of infants at 6 weeks, 4 months and 8 months, respectively. Pacifier use was reported in 38%, 50% and 33% at the respective surveys. As the age of the twins increased, mothers were significantly more likely to be concerned about deformational plagiocephaly in Twin 1 than in Twin 2.

CONCLUSION

Despite a lack of evidence of the risks or benefits of cobedding, this practice was very popular, especially in the younger infants. More research is needed to establish the safety of cobedding in relation to the risk of SIDS.

Concurrent risks in sudden infant death syndrome

BACKGROUND

Despite improved education on safe sleep, infants are still exposed to multiple risks for sudden infant death syndrome (SIDS). Variability among health care providers continues to exist regarding knowledge of risk factors and the provision of education to caregivers.

OBJECTIVE

To enhance the content and delivery of SIDS risk-reduction initiatives by physicians and other health care providers and to provide them with a context for evaluating their discussions of risks and compensatory strategies, we sought to raise awareness of the frequency of risk factors in SIDS cases, patterns of co-occurrence, associations between modifiable and nonmodifiable risks, and the rarity of cases without risk.

DESIGN AND METHODS

In a population-based retrospective review of 244 (97%) New Jersey SIDS cases (1996-2000), we assessed the frequencies and co-occurrences of modifiable (maternal and paternal smoking, nonsupine sleep or prone status at discovery, bed-sharing, or scene risks) and nonmodifiable (upper respiratory infection or <37 weeks' gestational age) risks.

RESULTS

Nonsupine sleep occurred in 70.4% of cases with data on position (159 of 226). Thirteen cases were of infants who were discovered prone, with an increased positional risk to 76.1%, in which 87% contained additional risks. Maternal smoking occurred in 42.6% (92 of 216) of the cases with data on this risk, and 98% among those cases had additional risks. At least 1 risk was found in 96% of the cases, and 78% had 2 to 7 risks. Of the 9 of 244 risk-free cases (3.7%), 7 lacked data on 2 to 5 risks per case. On the basis of the complete data, only 2 (0.8%) of all 244 cases were risk free. When nonmodifiable risks were excluded, 5.3% of the cases met this definition.

CONCLUSIONS

Risk-free and single-risk SIDS cases are rare, and most contain multiple risks. Parent education should be comprehensive and address compensatory strategies for nonmodifiable risks.

The German case-control scene investigation study on SIDS: epidemiological approach and main results

The present study, which was part of the German SIDS Study (GeSID), enrolled sudden infant death syndrome (SIDS) cases and population controls and obtained objective scene data via specifically trained observers shortly after discovery of each dead infant. Infants who had died suddenly and unexpectedly at ages between 8 and 365 days were enrolled in five regions of Germany between November 1998 and October 2001. Shortly after discovery of each dead infant, a specially trained doctor of legal medicine visited the bereaved family at home. Data were obtained by measurements and observations. Dead infants underwent a standardised autopsy, additional information being obtained by standardised parent interviews. Investigation of the sleep environment and wake-up scene in matched controls followed the same protocol. A total of 52 SIDS cases and 154 controls were enrolled, 58% were boys, and median age of cases vs. controls was 126 vs. 129 days. Risk factors in the sleeping environment were pillow use (adjusted OR 4.3; 95%CI 1.6-11.6), heavy duvets (OR 4.4; 1.5-13.3), soft underlay (OR 3.0; 1.1-8.7), face covered by bedding (OR 15.8; 2.5-102.1) and entire body covered by bedding (OR 35.5; 5.5-228.3). Using a standardised protocol, including objective measurements of the sleep environment and a case-control design, this study was able to confirm many risk factors for SIDS.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Changing Hospital Newborn Nursery Practice: Results from a Statewide “Back to Sleep” Nurses Training Program

OBJECTIVE

In response to findings from a statewide survey of hospital nurses, the authors designed, conducted, and evaluated a "Back to Sleep" nursing curriculum and training program in Missouri hospitals using two distinct training formats. This article evaluates the initial and follow-up outcomes for training participants and assesses the impact of training format on participant outcomes.

METHODS

Participants selected training format by hospital site. In each training format, participants responded to a pre and post test questionnaire measuring knowledge, beliefs, and current infant care behaviors as well as satisfaction with the training. Three months after completion of all statewide trainings, the authors also conducted a follow-up survey.

RESULTS

Nurses who participated in the training reported statistically significant improvements in knowledge and "Back to Sleep" adherent beliefs. Over 98% of participants (N=515) intended to place infants in back-only sleep positions following the training. Knowledge, attitudes, and practice intentions were significantly improved across both training formats. Additionally, follow-up survey respondents statewide (N=295) reported lasting improvements, including 63% of nurses reportedly using supine-only sleep position for infants after the first 24 h of life, compared to 28% in the original statewide survey.

CONCLUSIONS

Further research is needed to determine the long-term impact of this intervention and assess its applicability beyond this initial implementation. Ultimately, the findings from the evaluation of this pilot intervention and nursing-specific "Back to Sleep" curriculum demonstrate that it has a promising effect on risk-reduction adherence in hospital settings where parent observations of safe sleep behavior first occur.