A multivariate "time based" analysis of SIDS risk factors

Maternal intentions towards infant sleeping practices in Ireland

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Circumstances and factors of sleep-related sudden infancy deaths in Japan

Background

Sudden unexpected death in infancy (SUDI) comprises both natural and unnatural causes of death. However, few epidemiological surveys have investigated SUDI in Japan.

Objective

This retrospective study was conducted to investigate the latest trends of circumstances and risk factors of SUDI cases in which collapse occurred during sleep.

Methods

Forensic pathology sections from eight universities participated in the selection of subjects from 2013 to 2018. Data obtained from the checklist form were analyzed based on information at postmortem.

Results

There were 259 SUDI cases consisting of 145 male infants and 114 female infants with a mean birth weight of 2888 ± 553 and 2750 ± 370 g, respectively. Deaths most frequently occurred among infants at 1 month of age (18%). According to population data as the control, the odds ratio (95% confidence interval) of mother’s age ≤19 years was 11.1 (6.9–17.7) compared with ages 30–39. The odds ratio for the fourth- and later born infants was 5.2 (3.4–7.9) compared with the frequency of first-born infants. The most frequent time of day for discovery was between 7 and 8 o’clock, and the time difference from the last seen alive was a mean of 4.1 h. Co-sleeping was recorded for 61%, and the prone position was found for 40% of cases at discovery. Mother’s smoking habit exhibited an odds ratio of 4.5 (2.9–5.8).

Conclusion

This study confirmed the trends that have been observed for sudden infant death syndrome; particularly, very high odds ratios were evident for teenage mothers and later birth order in comparison with those in other developed countries. Neglect was suspected in some cases of the prolonged time to discovery of unreactive infants. To our knowledge, this is the first report of an extensive survey of SUDI during sleep in Japan.

Duration of Breastfeeding and Risk of SIDS: An Individual Participant Data Meta-analysis

CONTEXT

Sudden infant death syndrome (SIDS) is a leading cause of postneonatal infant mortality. Our previous meta-analyses showed that any breastfeeding is protective against SIDS with exclusive breastfeeding conferring a stronger effect.The duration of breastfeeding required to confer a protective effect is unknown.

OBJECTIVE

To assess the associations between breastfeeding duration and SIDS.

DATA SOURCES

Individual-level data from 8 case-control studies.

STUDY SELECTION

Case-control SIDS studies with breastfeeding data.

DATA EXTRACTION

Breastfeeding variables, demographic factors, and other potential confounders were identified. Individual-study and pooled analyses were performed.

RESULTS

A total of 2267 SIDS cases and 6837 control infants were included. In multivariable pooled analysis, breastfeeding for <2 months was not protective (adjusted odds ratio [aOR]: 0.91, 95% confidence interval [CI]: 0.68-1.22). Any breastfeeding ≥2 months was protective, with greater protection seen with increased duration (2-4 months: aOR: 0.60, 95% CI: 0.44-0.82; 4-6 months: aOR: 0.40, 95% CI: 0.26-0.63; and >6 months: aOR: 0.36, 95% CI: 0.22-0.61). Although exclusive breastfeeding for <2 months was not protective (aOR: 0.82, 95% CI: 0.59-1.14), longer periods were protective (2-4 months: aOR: 0.61, 95% CI: 0.42-0.87; 4-6 months: aOR: 0.46, 95% CI: 0.29-0.74).

LIMITATIONS

The variables collected in each study varied slightly, limiting our ability to include all studies in the analysis and control for all confounders.

CONCLUSIONS

Breastfeeding duration of at least 2 months was associated with half the risk of SIDS. Breastfeeding does not need to be exclusive to confer this protection.

Co-bedding in neonatal nursery for promoting growth and neurodevelopment in stable preterm twins

BACKGROUND

The increased birth rate of twins during recent decades and the improved prognosis of preterm infants have resulted in the need to explore measures that could optimize their growth and neurodevelopmental outcomes. It has been postulated that co-bedding simulates twins' intrauterine experiences in which co-regulatory behaviors between them are observed. These behaviors are proposed to benefit twins by reducing their stress, which may promote growth and development. However, in practice, uncertainty surrounds the benefit-risk profile of co-bedding.

OBJECTIVES

We aimed to assess the effectiveness of co-bedding compared with separate (individual) care for stable preterm twins in the neonatal nursery in promoting growth and neurodevelopment and reducing short- and long-term morbidities, and to determine whether co-bedding is associated with significant adverse effects.As secondary objectives, we sought to evaluate effects of co-bedding via the following subgroup analyses: twin pairs with different weight ranges (very low birth weight [VLBW] < 1500 grams vs non-VLBW), twins with versus without significant growth discordance at birth, preterm versus borderline preterm twins, twins co-bedded in incubator versus cot at study entry, and twins randomized by twin pair versus neonatal unit.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group (CNRG). We used keywords and medical subject headings (MeSH) to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 2), MEDLINE (via PubMed), EMBASE (hosted by EBSCOHOST), the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and references cited in our short-listed articles, up to February 29, 2016.

SELECTION CRITERIA

We included randomized controlled trials with randomization by twin pair and/or by neonatal unit. We excluded cross-over studies.

DATA COLLECTION AND ANALYSIS

We extracted data using standard methods of the CNRG. Two review authors independently assessed the relevance and risk of bias of retrieved records. We contacted the authors of included studies to request important information missing from their published papers. We expressed our results using risk ratios (RRs) and mean differences (MDs) when appropriate, along with 95% confidence intervals (95% CIs). We adjusted the unit of analysis from individual infants to twin pairs by averaging measurements for each twin pair (continuous outcomes) or by counting outcomes as positive if developed by either twin (dichotomous outcomes).

MAIN RESULTS

Six studies met the inclusion criteria; however, only five studies provided data for analysis. Four of the six included studies were small and had significant limitations in design. As each study reported outcomes differently, data for most outcomes were effectively contributed by a single study. Study authors reported no differences between co-bedded twins and twins receiving separate care in terms of rate of weight gain (MD 0.20 grams/kg/d, 95% CI -1.60 to 2.00; one study; 18 pairs of twins; evidence of low quality); apnea, bradycardia, and desaturation (A/B/D) episodes (RR 0.85, 95% CI 0.18 to 4.05; one study; 62 pairs of twins; evidence of low quality); episodes in co-regulated states (MD 0.96, 95% CI -3.44 to 5.36; one study; three pairs of twins; evidence of very low quality); suspected or proven infection (RR 0.84, 95% CI 0.30 to 2.31; three studies; 65 pairs of twins; evidence of very low quality); length of hospital stay (MD -4.90 days, 95% CI -35.23 to 25.43; one study; three pairs of twins; evidence of very low quality); and parental satisfaction measured on a scale of 0 to 55 (MD -0.38, 95% CI -4.49 to 3.73; one study; nine pairs of twins; evidence of moderate quality). Although co-bedded twins appeared to have lower pain scores 30 seconds after heel lance on a scale of 0 to 21 (MD -0.96, 95% CI -1.68 to -0.23; two studies; 117 pairs of twins; I(2) = 75%; evidence of low quality), they had higher pain scores 90 seconds after the procedure (MD 1.00, 95% CI 0.14 to 1.86; one study; 62 pairs of twins). Substantial heterogeneity in the outcome of infant pain response after heel prick at 30 seconds post procedure and conflicting results at 30 and 90 seconds post procedure precluded clear conclusions.

AUTHORS' CONCLUSIONS

Evidence on the benefits and harms of co-bedding for stable preterm twins was insufficient to permit recommendations for practice. Future studies must be adequately powered to detect clinically important differences in growth and neurodevelopment. Researchers should assess harms such as infection, along with medication errors and caregiver satisfaction.

Sudden death of an infant with cardiac, nervous system and genetic involvement--a case report

Abstract

We present a case of sudden death of a 1-month-old male infant with heart, brainstem and genetic polymorphism involvement. Previously considered quite healthy, the child died suddenly and unexpectedly during sleep. The autopsy protocol included an in-depth anatomopathological examination of both the autonomic nervous system and the cardiac conduction system, and molecular analysis of the serotonin transporter gene promoter region, in which a specific genetic condition seems to be associated with sudden infant death. Histological examination revealed the presence of congenital cardiac alterations (hypertrophic cardiomyopathy and an accessory Mahaim fiber in the cardiac conduction system), severe hypodevelopment of all the raphe nuclei and a heterozygous genotype L/S related to the serotonin transporter gene. The sudden death of this infant was the unavoidable outcome of a complex series of congenital anomalies, each predisposing to SIDS.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/3480540091031788

Co-bedding in neonatal nursery for promoting growth and neurodevelopment in stable preterm twins

BACKGROUND

With the increased birth rate of twins during the recent decades and improved prognosis of preterm infants, there is a need to explore measures that could optimise their growth and neurodevelopmental outcomes. It has been postulated that co-bedding simulates the twins' intrauterine experiences in which co-regulatory behaviours between the twins are observed. These behaviours are proposed to benefit the twins by reducing their stress, which may promote growth and development. However, uncertainties exist on the benefit-risk profile of co-bedding in practice.

OBJECTIVES

We aimed to assess the effects of co-bedding on growth, and other clinically relevant physiological and neurodevelopmental outcomes for stable preterm twins.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group (CNRG). We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2012, Issue 7), MEDLINE (via PubMed), EMBASE (hosted by EBCHOST), CINAHL and references cited in our shortlisted articles using keywords and MesH headings, up to July 2012.

SELECTION CRITERIA

We included randomised controlled trials with randomisation either at the level of each twin pair and/or at the level of neonatal unit. We excluded cross-over studies.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the CNRG. Two review authors independently assessed the relevance and risk of bias of the retrieved records. We contacted the authors of the included studies if important information was missing from their published papers. We expressed our results using risk ratio (RR) and mean difference (MD) where appropriate with their 95% confidence intervals (CIs). We adjusted the unit of analysis from individual infants to twin pairs by averaging the measurement for each twin pair (continuous outcome) or by counting the outcome as positive if any of the twins developed the outcome (dichotomous outcome).

MAIN RESULTS

Five studies met the inclusion criteria; however, data were only available for analysis in four studies. Four of the five included studies were small and had significant limitations in design. As each study reported the outcomes differently, data for most of the outcomes were effectively contributed by a single study. There were no differences between co-bedded twins and twins that received separate care in the rate of weight gain (MD 0.20 grams/kg/day, 95% CI: -1.60 to 2.00), apnoea, bradycardia and desaturation (A/B/D) episodes (RR: 0.85, 95% CI: 0.18 to 4.05; 1 study), length of hospital stay (MD -4.90 days, 95% CI: -35.23 to 25.43) and infection rates (typical RR: 0.84, 95% CI: 0.30 to 2.31; 3 studies). There were also no differences in parental perceptions of care. Co-bedded twins appeared to spend more time crying, but they also seemed to spend more time in quiet sleep. There was low or very low quality of evidence across all the outcomes.

AUTHORS' CONCLUSIONS

There was insufficient evidence on the benefits and harms of co-bedding stable preterm twins to make any recommendation in practice. There is a need for future studies that are adequately powered to detect clinically important differences in growth and neurodevelopment. Such studies should also assess harms including infections and medication errors, and caregiver satisfaction.

Do immunisations reduce the risk for SIDS? A meta-analysis

BACKGROUND

There are claims that immunisations cause sudden infant death syndrome (SIDS), but some studies have found either no association or that they are associated with a reduced risk of SIDS.

AIMS

To conduct a meta-analysis examining the relationship between immunisation and SIDS.

METHODS

Nine case-controls studies were identified examining this association, of which four adjusted for potential confounders.

RESULTS

The summary odds ratio (OR) in the univariate analysis suggested that immunisations were protective, but the presence of heterogeneity makes it difficult to combine these studies. The summary OR for the studies reporting multivariate ORs was 0.54 (95% CI=0.39-0.76) with no evidence of heterogeneity.

CONCLUSIONS

Immunisations are associated with a halving of the risk of SIDS. There are biological reasons why this association may be causal, but other factors, such as the healthy vaccinee effect, may be important. Immunisations should be part of the SIDS prevention campaigns.

Maternal smoking and sudden infant death syndrome: epidemiological study related to pathology

Various risk factors have been postulated to be related to sudden infant death syndrome (SIDS). Despite its reduction, thanks to the "Back to Sleep" campaign, SIDS is still a major cause of infant mortality in the first year of life. The purpose of this study was to correlate the different risk factors with the autopsy results and thus to determine if one or more of these variables is really specific for SIDS. We collected 128 sudden infant death victims with clinical diagnosis of SIDS and performed a complete autopsy with in-depth histology on serial sections, particularly of the brainstem, in accordance with our necropsy protocol. Histopathologic and immunohistochemical examination of the central autonomic nervous system revealed, in 78 cases of the SIDS group, the following anomalies: hypodevelopment of the arcuate nucleus, somatostatin positive hypoglossus nucleus, tyrosine hydroxylase negativity in the locus coeruleus, gliosis, and hypoplasia of the hypoglossus nucleus. A significant relation was found between maternal smoke and brainstem alterations.

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

BACKGROUND

It is unclear if it is safe for babies to bed share with adults. In Ireland 49% of sudden infant death syndrome (SIDS) cases occur when the infant is bed-sharing with an adult.

OBJECTIVE

To evaluate the effect of bed-sharing during the last sleep period on risk factors for SIDS in Irish infants.

DESIGN

An 8 year (1994-2001) population based case control study of 287 SIDS cases and 831 controls matched for date, place of birth, and sleep period. Odds ratios and 95% confidence intervals were calculated by conditional logistic regression.

RESULTS

The risk associated with bed-sharing was three times greater for infants with low birth weight for gestation (UOR 16.28 v 4.90) and increased fourfold if the combined tog value of clothing and bedding was > or =10 (UOR 9.68 v 2.34). The unadjusted odds ratio for bed-sharing was 13.87 (95% CI 9.58 to 20.09) for infants whose mothers smoked and 2.09 (95% CI 0.98 to 4.39) for non-smokers. Age of death for bed-sharing and sofa-sharing infants (12.8 and 8.3 weeks, respectively) was less than for infants not sharing a sleep surface (21.0 weeks, p<0.001) and fewer bed-sharing cases were found prone (5% v 32%; p = 0.001).

CONCLUSION

Risk factors for SIDS vary according to the infant's sleeping environment. The increased risk associated with maternal smoking, high tog value of clothing and bedding, and low z scores of weight for gestation at birth is augmented further by bed-sharing. These factors should be taken into account when considering sleeping arrangements for young infants.

The changing concept of sudden infant death syndrome: diagnostic coding shifts, controversies regarding the sleeping environment, and new variables to consider in reducing risk

There has been a major decrease in the incidence of sudden infant death syndrome (SIDS) since the American Academy of Pediatrics (AAP) released its recommendation in 1992 that infants be placed down for sleep in a nonprone position. Although the SIDS rate continues to fall, some of the recent decrease of the last several years may be a result of coding shifts to other causes of unexpected infant deaths. Since the AAP published its last statement on SIDS in 2000, several issues have become relevant, including the significant risk of side sleeping position; the AAP no longer recognizes side sleeping as a reasonable alternative to fully supine sleeping. The AAP also stresses the need to avoid redundant soft bedding and soft objects in the infant's sleeping environment, the hazards of adults sleeping with an infant in the same bed, the SIDS risk reduction associated with having infants sleep in the same room as adults and with using pacifiers at the time of sleep, the importance of educating secondary caregivers and neonatology practitioners on the importance of "back to sleep," and strategies to reduce the incidence of positional plagiocephaly associated with supine positioning. This statement reviews the evidence associated with these and other SIDS-related issues and proposes new recommendations for further reducing SIDS risk.

Bedsharing and maternal smoking in a population-based survey of new mothers

OBJECTIVE

Sudden infant death syndrome (SIDS) remains the number 1 cause of postneonatal infant death. Prone infant sleep position and maternal smoking have been established as risk factors for SIDS mortality. Some studies have found that bedsharing is associated with SIDS, but, to date, there is only strong evidence for a risk among infants of smoking mothers and some evidence of a risk among young infants of nonsmoking mothers. Despite the lack of convincing scientific evidence, bedsharing with nonsmoking mothers remains controversial. In some states, nonsmoking mothers are currently being told that they should not bedshare with their infants, and mothers of infants who died of SIDS are told that they caused the death of their infant because they bedshared. The objective of this study was to explore the relationship between maternal smoking and bedsharing among Oregon mothers to explore whether smoking mothers, in contrast to nonsmoking mothers, are getting the message that they should not bedshare.

METHODS

Oregon Pregnancy Risk Assessment Monitoring System surveys a stratified random sample, drawn from birth certificates, of women after a live birth. Hispanic and non-Hispanic black, non-Hispanic Asian/Pacific Islander and non-Hispanic American Indian/Alaskan Native women, and non-Hispanic white women with low birth weight infants are oversampled to ensure sufficient numbers for stratified analysis. The sample then was weighted to reflect Oregon's population. In 1998-1999, 1867 women completed the survey (73.5% weighted response). The median time from birth to completion of the survey was 4 months. Women were asked whether they shared a bed with their infant "always," "almost always," "sometimes," or "never." Frequent bedsharing was defined as "always" or "almost always"; infrequent was defined as "sometimes" or "never."

RESULTS

Of all new mothers, 35.2% reported bedsharing frequently (always: 20.5%; almost always: 14.7%) and 64.8% infrequently (sometimes: 41.4%; never: 23.4%). Bedsharing among postpartum smoking mothers was 18.8% always, 12.6% almost always, 45.1% sometimes, and 23.6% never; this was not statistically different from among nonsmoking mothers. Results for prenatal smokers were similar. When stratified by race/ethnicity, there was no association between smoking and bedsharing in any racial or ethnic group. In univariable and multivariable logistic regression, there were no statistical differences in frequent or any bedsharing among either prenatal or postpartum smoking mothers compared with nonsmokers; the adjusted odds ratio for postpartum smokers who frequently bedshared was 0.73 (95% confidence interval [CI]: 0.42-1.25) and for any bedsharing was 1.05 (95% CI: 0.57-1.94). Results for prenatal smoking were similar. This is the first US population-based study to look at the prevalence of bedsharing among smoking and nonsmoking mothers. Bedsharing is common in Oregon, with 35.2% of mothers in Oregon reporting frequently bedsharing and an additional 41.4% sometimes bedsharing. There was no significant association between smoking and bedsharing for either prenatal or postpartum smokers among any racial or ethnic group. Smoking mothers were as likely to bedshare as nonsmoking mothers. The frequency of bedsharing in Oregon was similar to estimates from other sources. Our study has the advantage of being a population-based sample drawn from birth certificates, weighted for nonresponse.

CONCLUSIONS

Although a number of case series have raised concerns about the safety of mother-infant bedsharing, even among nonsmoking mothers, this has not yet been confirmed by careful, controlled studies. There have been 9 large-scale case-control studies of the relationship between bedsharing and SIDS. Three case-control studies did not stratify by maternal smoking status, but found no increased risk for SIDS. Six case control studies reported results stratified by maternal smoking status: 1 study, while asserting an association, provided an unexplained range of univariable odds ratios without CIs; 3 found no increased risk for older infants of nonsmoking mothers; and 2 found a risk only for infants <8-11 weeks of age. Despite the preponderance of evidence that bedsharing by nonsmoking mothers does not increase the risk for SIDS among older infants, the recent specter of bedsharing as a cause of SIDS, based on uncontrolled case series and medical examiners' anecdotal experience, has led some medical examiners to label a death "suffocation" or "overlay asphyxiation" simply because the infant was bedsharing at the time of death. This "diagnostic drift" may greatly complicate future studies of the relationship between bedsharing and SIDS. Epidemiologic evidence shows that there is little or no increased risk for SIDS among infants of nonsmoking mothers but increased risk among infants of smoking mothers and younger infants of nonsmoking mothers. It seems prudent to discourage bedsharing among all infants <3 months old. Young infants brought to bed to be breastfed should be returned to a crib when finished. It would be worthwhile for other researchers to reanalyze their previous data to evaluate the consistency of the interaction of young infant age and bedsharing. Large controlled studies that include infants who are identified as dying from SIDS, asphyxia, suffocation, and sudden unexplained infant death, analyzed separately and in combination, are needed to resolve this and other issues involving bedsharing, including the problem of diagnostic drift. Recommendations must be based on solid scientific evidence, which, to date, does not support the rejection of all bedsharing between nonsmoking mothers and their infants. Cribs should be available for those who want to use them. Nonsmoking mothers should not be pressured to abstain from bedsharing with their older infants; they should be provided with accurate, up-to-date scientific information. Infants also should not co-sleep with nonparents. In Oregon, if not elsewhere, the message that smoking mothers should not bedshare is not being disseminated effectively. Because it is not known whether the risk caused by smoking is associated with prenatal smoking, postpartum smoking, or both, bedsharing among either prenatal or postpartum smokers should be strongly discouraged. Much more public and private effort must be made to inform smoking mothers, in culturally competent ways, of the very significant risks of mixing bedsharing and smoking. Public health practitioners need to find new ways to inform mothers and providers that smoking mothers should not bedshare and that putting an infant of a nonsmoking mother to sleep in an adult bed should be delayed until 3 months of age.

Infection and food: a factor in sudden infant death syndrome?

Despite the identification of risk factors for sudden infant death syndrome (SIDS) and decreased SIDS rates in many countries, there is still no coherent, widely accepted, mechanistic explanation for SIDS. As an extension of our work on the infectious aetiology of SIDS, we have explored the prediction that infectious agents might reach susceptible infants and babies, via particular sources of food. In this ecological study, we demonstrated significant correlations between SIDS rates and exposure to meat from some sources, and we propose that more detailed studies be carried out.