A Risk Assessment and Planning Tool to Prevent Sudden Unexpected Death in Infancy: Development and Evaluation of The Baby Sleep Planner

BACKGROUND

Successful national safer sleep campaigns in the United Kingdom have lowered the death rates from sudden unexpected death in infancy (SUDI) over the past 3 decades, but deaths persist in socioeconomically deprived families. The circumstances of current deaths suggest that improvements in support for some families to follow safer sleep advice more consistently could save lives.

OBJECTIVE

This study aimed to develop and evaluate a risk assessment and planning tool designed to improve the uptake of safer sleep advice in families with infants at increased risk of SUDI.

METHODS

A co-design approach was used to develop the prototype interface of a web-based tool with 2 parts: an individual SUDI risk assessment at birth and a downloadable plan for safety during times of disruption. The advice contained within the tool is concordant with national guidance from the Lullaby Trust, the United Nations International Children's Emergency Fund (UNICEF), and the National Institute for Health and Care Excellence. User testing of the prototype tool was conducted by inviting health visitors, midwives, and family nurses to use it with families eligible for additional support. Qualitative interviews with health professionals and families allowed for iterative changes to the tool and for insights into its function and influence on parental behavior.

RESULTS

A total of 22 health professionals were enrolled in the study, of whom 20 (91%) were interviewed. They reported appreciating the functionality of the tool, which allowed them to identify at-risk families for further support. They felt that the tool improved how they communicated about risks with families. They suggested expanding its use to include relevance in the antenatal period and having versions available in languages other than English. They reported using the tool with 58 families; 20 parents gave consent to be interviewed by the research team about their experiences with the tool. Families were positive about the tool, appreciated the trustworthy information, and felt that it was useful and appropriate and that the plans for specific infant sleeps would be of benefit to them and other family members.

CONCLUSIONS

Our tool combines risk assessment and safety planning, both of which have the potential to improve the uptake of lifesaving advice. Refinements to the tool based on these findings have ensured that the tool is ready for further evaluation in a larger study before being rolled out to families with infants at increased risk.

Interventions to Improve Safer Sleep Practices in Families With Children Considered to Be at Increased Risk for Sudden Unexpected Death in Infancy: A Systematic Review

Background: Advice to families to follow infant care practices known to reduce the risks of Sudden Unexpected Death in Infancy (SUDI) has led to a reduction in deaths across the world. This reduction has slowed in the last decade with most deaths now occurring in families experiencing social and economic deprivation. A systematic review of the literature was commissioned by the National Child Safeguarding Practice Review Panel in England. The review covered three areas: interventions to improve engagement with support services, parental decision-making for the infant sleep environment, and interventions to improve safer sleep practices in families with infants considered to be at risk of SUDI. Aim: To describe the safer sleep interventions tested with families with infants at risk of SUDI and investigate what this literature can tell us about what works to reduce risk and embed safer sleep practices in this group. Methods: Eight online databases were systematically searched in December 2019. Intervention studies that targeted families with infants (0-1 year) at increased risk of SUDI were included. Studies were limited to those from Western Europe, North America or Australasia, published in the last 15 years. The Quality Assessment Tool for Studies with Diverse Designs was applied to assess quality. Data from included studies were extracted for narrative synthesis, including mode of delivery using Michie et al.'s Mode of Delivery Taxonomy. Results: The wider review returned 3,367 papers, with 23 intervention papers. Five types of intervention were identified: (1) infant sleep space and safer sleep education programs, (2) intensive or targeted home visiting services, (3) peer educators/ambassadors, (4) health education/raising awareness interventions, (5) targeted health education messages using digital media. Conclusion: Influencing behavior in families with infants at risk of SUDI has traditionally focused on "getting messages across," with interventions predominantly using education and awareness raising mechanisms. This review found evidence of interventions moving from "information giving" to "information exchange" models using personalized, longer term relationship-building models. This shift may represent an improvement in how safer sleep advice is implemented in families with infants at risk, but more robust evidence of effectiveness is required. Systematic Review Registration: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/901091/DfE_Death_in_infancy_review.pdf, identifier: CRD42020165302.

Physiological responses to cuddling babies with hypoxic-ischaemic encephalopathy during therapeutic hypothermia: an observational study

OBJECTIVES

To determine whether parents cuddling infants during therapeutic hypothermia (TH) would affect cooling therapy, cardiorespiratory or neurophysiological measures. The secondary aim was to explore parent-infant bonding, maternal postnatal depression and breastfeeding.

DESIGN

Prospective observational study.

SETTING

Two tertiary neonatal intensive care units (NICU).

PARTICIPANTS

Parents and their term-born infants (n=27) receiving TH and intensive care for neonatal hypoxic-ischaemic encephalopathy.

INTERVENTIONS

Cuddling up to 2 hours during TH using a standard operating procedure developed in the study (CoolCuddle).

MAIN OUTCOME MEASURES

Mean difference in temperature, cardiorespiratory and neurophysiological variables before, during and after the cuddle. Secondary outcomes were parental bonding, maternal postnatal depression and breastfeeding.

RESULTS

During 70 CoolCuddles (115 cumulative hours), there were measurable increases in rectal temperature (0.07°C (0.03 to 0.10)) and upper margin of amplitude-integrated electroencephalogram (1.80 µV (0.83 to 2.72)) and decreases in oxygen saturations (-0.57% (-1.08 to -0.05)) compared with the precuddle period. After the cuddle, there was an increase in end-tidal CO₂ (0.25 kPa (95% CI 0.14 to 0.35)) and mean blood pressure (4.09 mm Hg (95% CI 0.96 to 7.21)) compared with the precuddle period. From discharge to 8 weeks postpartum, maternal postnatal depression declined (13 (56.5%) vs 5 (23.8%), p=0.007); breastfeeding rate differed (71% vs 50%, p=0.043), but was higher than national average at discharge (70% vs 54.6%) and mother-infant bonding (median (IQR): 3 (0-6) vs 3 (1-4)) remained stable.

CONCLUSION

In this small study, CoolCuddle was associated with clinically non-significant, but measurable, changes in temperature, cardiorespiration and neurophysiology. No infant met the criteria to stop the cuddles or had any predefined adverse events. CoolCuddle may improve breastfeeding and requires investigation in different NICU settings.

Decision-making for the infant sleep environment among families with children considered to be at risk of sudden unexpected death in infancy: a systematic review and qualitative metasynthesis

BACKGROUND

Advice to families to sleep infants on their backs, avoid smoke exposure, reduce excess bedcovering and avoid specific risks associated with cosleeping has greatly reduced sudden unexpected death in infancy (SUDI) rates worldwide. The fall in rates has not been equal across all groups, and this advice has been less effective for more socially deprived families. Understanding decision-making processes of families with infants at risk would support the development of more effective interventions.

AIM

To synthesise the qualitative evidence on parental decision-making for the infant sleep environment among families with children considered to be at increased risk of SUDI.

METHODS

This study was one of three related reviews of the literature for the Child Safeguarding Practice Review Panel's National Review in England into SUDI in families where the children are considered at risk of harm. A systematic search of eight online databases was carried out in December 2019. Metasynthesis was conducted, with themes extracted from each paper, starting with the earliest publication first.

RESULTS

The wider review returned 3367 papers, with 16 papers (across 13 studies) specifically referring to parental decision-making. Six overall themes were identified from the synthesis: (1) knowledge as different from action; (2) external advice must be credible; (3) comfort, convenience and disruption to the routine; (4) plausibility and mechanisms of protection; (5) meanings of safety and risk mitigation using alternative strategies; and (6) parents' own expertise, experience and instincts.

CONCLUSION

Interventions that are intended to improve the uptake of safer sleep advice in families with infants at risk of sleep-related SUDI need to be based on credible advice with mechanisms of protection that are understandable, consistent with other sources, widened to all carers of the infant and fit within the complex practice of caring for infants.

Dysfunction of NaV1.4, a skeletal muscle voltage-gated sodium channel, in sudden infant death syndrome: a case-control study

BACKGROUND

Sudden infant death syndrome (SIDS) is the leading cause of post-neonatal infant death in high-income countries. Central respiratory system dysfunction seems to contribute to these deaths. Excitation that drives contraction of skeletal respiratory muscles is controlled by the sodium channel NaV1.4, which is encoded by the gene SCN4A. Variants in NaV1.4 that directly alter skeletal muscle excitability can cause myotonia, periodic paralysis, congenital myopathy, and myasthenic syndrome. SCN4A variants have also been found in infants with life-threatening apnoea and laryngospasm. We therefore hypothesised that rare, functionally disruptive SCN4A variants might be over-represented in infants who died from SIDS.

METHODS

We did a case-control study, including two consecutive cohorts that included 278 SIDS cases of European ancestry and 729 ethnically matched controls without a history of cardiovascular, respiratory, or neurological disease. We compared the frequency of rare variants in SCN4A between groups (minor allele frequency <0·00005 in the Exome Aggregation Consortium). We assessed biophysical characterisation of the variant channels using a heterologous expression system.

FINDINGS

Four (1·4%) of the 278 infants in the SIDS cohort had a rare functionally disruptive SCN4A variant compared with none (0%) of 729 ethnically matched controls (p=0·0057).

INTERPRETATION

Rare SCN4A variants that directly alter NaV1.4 function occur in infants who had died from SIDS. These variants are predicted to significantly alter muscle membrane excitability and compromise respiratory and laryngeal function. These findings indicate that dysfunction of muscle sodium channels is a potentially modifiable risk factor in a subset of infant sudden deaths.

FUNDING

UK Medical Research Council, the Wellcome Trust, National Institute for Health Research, the British Heart Foundation, Biotronik, Cardiac Risk in the Young, Higher Education Funding Council for England, Dravet Syndrome UK, the Epilepsy Society, the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health, and the Mayo Clinic Windland Smith Rice Comprehensive Sudden Cardiac Death Program.

Cavernous Haemangioma with Kasabach-Merritt Syndrome: Treatment with Alpha-Interferon

A small number of patients with haemangioma need treatment for serious complications such as Kasabach-Merritt syndrome, cardiac failure and obstruction of the airway. We report on the management of an infant with Kasabach-Merritt syndrome.

Mothers' knowledge and attitudes to sudden infant death syndrome risk reduction messages: results from a UK survey

OBJECTIVE

To investigate mothers' knowledge of reducing the risks for sudden infant death syndrome (SIDS) and attitudes towards safer sleep practices.

DESIGN AND SETTING

A cross-sectional survey was carried out in deprived areas of Bristol, UK. Recruitment took place in 2014 at local health visitor-led baby clinics.

PARTICIPANTS

Of 432 mothers approached, 400 (93%) completed the face-to-face survey. Participants with infants at 'higher' risk of SIDS (using an algorithm based on a previous observational study) were compared with those at 'lower' risk.

MAIN OUTCOME MEASURES

The survey asked participants to recall three SIDS risk reduction strategies (unprompted), and scored responses to 14 SIDS risk-related infant sleep scenarios (prompted).

RESULTS

Overall, 48/400 (12%) mothers were classified as higher risk. Mothers in the higher risk group were less likely to breast feed (multivariate OR=3.59(95% CI 1.46 to 8.86)), less likely to be able to cite two or more unprompted correct SIDS risk reduction strategies (multivariate OR=2.05(95% CI 1.02 to 4.13)) and scored lower on prompted safer sleep scenarios overall.Notably, only 206/400 (52%) of all mothers surveyed (33% in the higher risk group) from these deprived areas in Bristol identified infant sleep position as a risk reduction strategy for SIDS, despite 25 years of campaigns.

CONCLUSIONS

Mothers in the higher risk group were disadvantaged when it came to some aspects of knowledge of SIDS risk reduction and attitudes to safer sleep. The initial 'Back-to Sleep' message that dramatically reduced these deaths a generation ago needs more effective promotion for today's generation of mothers.

Estimating discharge dates using routinely collected data: improving the preparedness of parents of preterm infants for discharge home

The length of stay for moderately preterm infants has progressively become shorter in the UK in recent years but staff still commonly inform parents that their baby will go home around their estimated date of delivery (EDD). Parents need as much notice as possible to prepare for the discharge of their baby, and to gain the necessary skills and knowledge to care for their infant safely. We report the use of routinely collected neonatal data to develop and implement a simple centile chart for date of discharge from hospital, which allows staff and parents to predict the likely discharge date more accurately for preterm infants, most of whom now go home more than 3 weeks before their EDD. This information allows better and timelier planning for discharge of such infants, by parents and staff.

Factors influencing maternal decision-making for the infant sleep environment in families at higher risk of SIDS: a qualitative study

OBJECTIVE

Qualitative interviews with mothers of babies at higher risk of sudden infant death syndrome (SIDS) were carried out to understand their views and decision-making process on the infant sleep environment and safe sleep messages.

DESIGN AND SETTING

Twenty semi-structured interviews were conducted between February and November 2014 in deprived areas of Bristol, UK. Mothers were asked about their decision-making for the infant sleep environment and safe sleep messages including infant sleep position, co-sleeping, smoking, dummy use, feeding and disrupted routines. The interviews were transcribed, coded and thematic analysis carried out.

PARTICIPANTS

Participants were invited based on an algorithm developed in a previous SIDS case control study that identified an increased risk of SIDS from four demographic characteristics: young maternal age, smoking during pregnancy, three or more children, and a measure of deprivation. The presence of three, or more characteristics led to being invited to take part in the qualitative study.

RESULTS

Factors influencing mothers' adherence to the safe sleep messages included previous experience and the credibility of the advice given. They described disrupted routines that led to risky scenarios with a belief that occasional risks were acceptable. Where circumstances made following the advice more difficult they found alternative strategies to reduce the risk, including the use of movement monitors, regular checking and a belief that lighter maternal sleep in the presence of a baby was protective.

CONCLUSIONS

Safer sleep messages should be tailored to fit with the lived realities of mothers, especially those at higher risk. The traditional list of 'do's' and 'don'ts' was not well accepted by this group. Interventions that seek to influence this higher-risk group should acknowledge mothers' own protective instincts and consider their beliefs and understanding behind the safer sleep messages if they are to be effective and encourage this group to change.

Swaddling and the Risk of Sudden Infant Death Syndrome: A Meta-analysis

CONTEXT

Swaddling is a traditional practice of wrapping infants to promote calming and sleep. Although the benefits and risks of swaddling in general have been studied, the practice in relation to sudden infant death syndrome remains unclear.

OBJECTIVE

The goal of this study was to conduct an individual-level meta-analysis of sudden infant death syndrome risk for infants swaddled for sleep.

DATA SOURCES

Additional data on sleeping position and age were provided by authors of included studies.

STUDY SELECTION

Observational studies that measured swaddling for the last or reference sleep were included.

DATA EXTRACTION

Of 283 articles screened, 4 studies met the inclusion criteria.

RESULTS

There was significant heterogeneity among studies (I(2) = 65.5%; P = .03), and a random effects model was therefore used for analysis. The overall age-adjusted pooled odds ratio (OR) for swaddling in all 4 studies was 1.58 (95% confidence interval [CI], 0.97-2.58). Removing the most recent study conducted in the United Kingdom reduced the heterogeneity (I(2) = 28.2%; P = .25) and provided a pooled OR (using a fixed effects model) of 1.38 (95% CI, 1.05-1.80). Swaddling risk varied according to position placed for sleep; the risk was highest for prone sleeping (OR, 12.99 [95% CI, 4.14-40.77]), followed by side sleeping (OR, 3.16 [95% CI, 2.08-4.81]) and supine sleeping (OR, 1.93 [95% CI, 1.27-2.93]). Limited evidence suggested swaddling risk increased with infant age and was associated with a twofold risk for infants aged >6 months.

LIMITATIONS

Heterogeneity among the few studies available, imprecise definitions of swaddling, and difficulties controlling for further known risks make interpretation difficult.

CONCLUSIONS

Current advice to avoid front or side positions for sleep especially applies to infants who are swaddled. Consideration should be given to an age after which swaddling should be discouraged.

Does family-centred neonatal discharge planning reduce healthcare usage? A before and after study in South West England

OBJECTIVE

To implement parent-oriented discharge planning (Train-to-Home) for preterm infants in neonatal care.

DESIGN

Before and after study, investigating the effects of the intervention during two 11-month periods before and after implementation.

SETTING

Four local neonatal units (LNUs) in South West England.

PARTICIPANTS

Infants without major anomalies born at 27-33 weeks' gestation admitted to participating units, and their parents.

TRAIN-TO-HOME INTERVENTION

A family-centred discharge package to increase parents' involvement and understanding of their baby's needs, comprising a train graphic and supporting care pathways to facilitate parents' understanding of their baby's progress and physiological maturation, combined with improved estimation of the likely discharge date.

MAIN OUTCOME MEASURES

Perceived Maternal Parenting Self-Efficacy (PMP S-E) scores, infant length of stay (LOS) and healthcare utilisation for 8 weeks following discharge.

RESULTS

Parents reported that the Train-to-Home improved understanding of their baby's progress and their preparedness for discharge. Despite a lack of change in PMP S-E scores with the intervention, the number of post-discharge visits to emergency departments (EDs) fell from 31 to 20 (p<0.05), with a significant reduction in associated healthcare costs (£3400 to £2200; p<0.05) after discharge. In both study phases, over 50% of infants went home more than 3 weeks before their estimated date of delivery (EDD), though no reduction in LOS occurred.

CONCLUSIONS

Despite the lack of measurable effect on the parental self-efficacy scores, the reduction in ED attendances and associated costs supports the potential value of this approach.

Sudden unexpected death in infancy: aetiology, pathophysiology, epidemiology and prevention in 2015

Despite the fall in numbers of unexpected infant deaths that followed the 'Back to Sleep' campaigns in the early 1990 s in the UK and many other countries, such deaths remain one of the largest single groups of deaths in the postneonatal period in many Western countries. Changes in the ways in which unexpected infant deaths are categorised by pathologists and coroners, and increasing reluctance to use the term 'sudden infant death syndrome', make assessment of nationally and internationally collected data on incidence potentially inaccurate and confusing. In this paper, we review current understanding of the epidemiology and aetiology of unexpected deaths in infancy, and current hypotheses on the pathophysiology of the processes that may lead to death. We also review interventions that have been adopted, with variable degrees of effectiveness in efforts to reduce the numbers of deaths, and new approaches that offer the possibility of prevention in the future.

Active robust optimization: enhancing robustness to uncertain environments

Many real world optimization problems involve uncertainties. A solution for such a problem is expected to be robust to these uncertainties. Commonly, robustness is attained by choosing the solution's parameters such that the solution's performance is less influenced by negative effects of the uncertain parameters' variations. This robustness may be viewed as a passive robustness, because once the solution's parameters are chosen, the robustness is inherent in the solution and no further action, to suppress the effect of uncertainties, is expected. However, it is acknowledged that enhanced robustness comes at the expense of peak performances. In this paper, active robust optimization is presented as a new robust optimization approach. It considers products that are able to adapt to environmental changes. The enhanced robustness of these solutions is attained by adaptation, which reduces the loss in performance due to environmental changes. A new optimization problem named active robust optimization problem is formulated. The problem amalgamates robust optimization with dynamic optimization to evaluate the performance of a candidate solution, while considering possible environmental conditions. The adaptation's influence on the solution's performance and cost is considered as well. Hence, the problem is formulated as a multiobjective problem that simultaneously aims at low costs and high performance. Since these goals are commonly in conflict, the solution is a set of optimal adaptive solutions. An evolutionary algorithm is proposed in order to evolve this set. An example of optimizing an adaptive optical table is provided. It is shown that an adaptive product, which is an outcome of the suggested approach, may be superior to an equivalent product that is not adaptive.

Bed-sharing in the absence of hazardous circumstances: is there a risk of sudden infant death syndrome? An analysis from two case-control studies conducted in the UK

Objective

The risk of sudden infant death syndrome (SIDS) among infants who co-sleep in the absence of hazardous circumstances is unclear and needs to be quantified.

Design

Combined individual-analysis of two population-based case-control studies of SIDS infants and controls comparable for age and time of last sleep.

Setting

Parents of 400 SIDS infants and 1386 controls provided information from five English health regions between 1993–6 (population: 17.7 million) and one of these regions between 2003–6 (population:4.9 million).

Results

Over a third of SIDS infants (36%) were found co-sleeping with an adult at the time of death compared to 15% of control infants after the reference sleep (multivariate OR = 3.9 [95% CI: 2.7–5.6]). The multivariable risk associated with co-sleeping on a sofa (OR = 18.3 [95% CI: 7.1–47.4]) or next to a parent who drank more than two units of alcohol (OR = 18.3 [95% CI: 7.7–43.5]) was very high and significant for infants of all ages. The risk associated with co-sleeping next to someone who smoked was significant for infants under 3 months old (OR = 8.9 [95% CI: 5.3–15.1]) but not for older infants (OR = 1.4 [95% CI: 0.7–2.8]). The multivariable risk associated with bed-sharing in the absence of these hazards was not significant overall (OR = 1.1 [95% CI: 0.6–2.0]), for infants less than 3 months old (OR = 1.6 [95% CI: 0.96–2.7]), and was in the direction of protection for older infants (OR = 0.1 [95% CI: 0.01–0.5]). Dummy use was associated with a lower risk of SIDS only among co-sleepers and prone sleeping was a higher risk only among infants sleeping alone.

Conclusion

These findings support a public health strategy that underlines specific hazardous co-sleeping environments parents should avoid. Sofa-sharing is not a safe alternative to bed-sharing and bed-sharing should be avoided if parents consume alcohol, smoke or take drugs or if the infant is pre-term.

Sleep patterns in children with autistic spectrum disorders: a prospective cohort study

OBJECTIVE

To investigate longitudinal sleep patterns in children with autistic spectrum disorders (ASDs).

STUDY DESIGN

Prospective longitudinal study using Avon Longitudinal Study of Parents and Children, an English cohort born in 1991-1992. Parental reports of sleep duration were collected by questionnaires at 8 time points from 6 months to 11 years. Children with an ASD diagnosis at age 11 years (n=73) were identified from health and education records.

RESULTS

From aged 30 months to 11 years old, children with ASD slept for 17-43 min less each day than contemporary controls. No significant difference in total sleep duration was found in infancy, but from 30 months of age children with ASD slept less than their peers, a difference that remained significant after adjusting for sex, ethnicity, high parity and epilepsy. The reduction in total sleep was wholly due to changes in night rather than daytime sleep duration. Night-time sleep duration was shortened by later bedtimes and earlier waking times. Frequent waking (3 or more times a night) was also evident among the children with ASD from 30 months of age. Age-specific decreases of >1SD within individuals in sleep duration across adjacent time points was a predictor of ASD between 18 months and 30 months of age (p=0.04) and from 30 months to 42 months (p=0.02).

CONCLUSIONS

Sleep duration in children with ASD is reduced from 30 months of age and persists until adolescence.

Pareto front estimation for decision making

The set of available multi-objective optimisation algorithms continues to grow. This fact can be partially attributed to their widespread use and applicability. However, this increase also suggests several issues remain to be addressed satisfactorily. One such issue is the diversity and the number of solutions available to the decision maker (DM). Even for algorithms very well suited for a particular problem, it is difficult-mainly due to the computational cost-to use a population large enough to ensure the likelihood of obtaining a solution close to the DM's preferences. In this paper we present a novel methodology that produces additional Pareto optimal solutions from a Pareto optimal set obtained at the end run of any multi-objective optimisation algorithm for two-objective and three-objective problem instances.

Sleep patterns in children with ADHD: a population-based cohort study from birth to 11 years

Associations between sleep duration and disturbance in infancy and early childhood and attention deficit hyperactivity disorder diagnoses were investigated. Data from the Avon Longitudinal Study of Parents and Children, a population-based prospective longitudinal birth-cohort study of children born in 1991–1992 in South-West England, were employed. Eight thousand, one hundred and ninety-five children were assessed using the Development and Well-Being Assessment. One hundred and seventy-three cases (2.1%) met criteria for attention deficit hyperactivity disorder. Parental report at eight time points showed children with attention deficit hyperactivity disorder slept less than peers. Absolute differences were small and mainly restricted to night-time sleep, with no strong evidence of differences from controls, except at 69 months {5 years 9 months; 12 min (95% CI: 5–19), P = 0.001}, at 81 months {6 years 9 months; 15 min (95% CI: 8–22), P < 0.001} and at 115 months {9 years 7 months; 11 min (95% CI: 4–18), P = 0.001}. The attention deficit hyperactivity disorder group had more night-waking at every age, significant from about 5 years. When tracking children’s sleep along a normative centiles chart, a shift in sleep duration from one centile to a lower centile was a useful predictor of attention deficit hyperactivity disorder. Age-specific decreases of >1SD in sleep duration across adjacent time points was a significant predictor of attention deficit hyperactivity disorder at 3–5 years (P = 0.047). In children with attention deficit hyperactivity disorder, shorter sleep duration and sleep disturbances appear early and predate the usual age of clinical diagnosis. The rate of change of sleep duration relative to an individual, rather than absolute sleep duration at any stage, may prove beneficial in identifying increased risk of attention deficit hyperactivity disorder.

Childhood sleep duration and associated demographic characteristics in an English cohort

STUDY OBJECTIVES

To provide reference data on sleep duration throughout childhood and explore the demographic characteristics associated with sleep.

DESIGN

Population-based prospective longitudinal birth-cohort study.

SETTING

South-West England, children born in 1991-1992 and followed since birth.

PARTICIPANTS

Eleven thousand five hundred children with repeat measures of sleep from birth based on parent-reported questionnaires. Data on daytime and nighttime sleep duration and timings and night awakenings at 8 timepoints from age 6 months to 11 years.

RESULTS

Total sleep duration steadily fell from 13 hours and 12 minutes during infancy to 9 hours and 49 minutes at 11 years of age. Compared with earlier studies, the younger children in this cohort slept for a shorter period. The variation in sleep duration was very wide: from 10 to 17 hours in early infancy, narrowing to 8.5 to 11 hours at 11 years. Half of the children at preschool age woke at least once during the night, but frequent waking (> 3 times) peaked in infancy (10% of all infants) and steadily declined in the preschool-aged years. Despite going to bed at the same time, girls slept consistently longer than boys (by 5-10 minutes). Children from low-income families went to bed later and woke up later, but there was little difference in total sleep duration. Children of younger mothers (< 21 years) slept longer, whereas children of older mothers (> 35 years) slept persistently less. Children in larger families tended to go to bed later, as did the minority group of non-White children in the cohort.

CONCLUSIONS

Given the wide natural variation of sleep in the childhood population, any recommendations on optimal sleep duration at any age must take into account considerable individual variability.

Relationship between bed sharing and breastfeeding: longitudinal, population-based analysis

OBJECTIVES

This is an investigation into the longitudinal patterns of bed sharing, the characteristics associated with those patterns, and the relationship with breastfeeding.

METHODS

The study used prospective, population-based data from the United Kingdom to investigate nocturnal bed sharing at 5 time points from birth to 4 years of age. Of 14 062 live births, 7447 (53%) had data available for all time points.

RESULTS

Latent class analysis identified 4 mutually exclusive groups, broadly described as nonsharers (66%), early bed sharers (only in infancy) (13%), late bed sharers (after the first year) (15%), and constant bed sharers (throughout the 4 years) (6%). The boy/girl ratio and the proportion of families of nonwhite ethnicity were slightly higher in all 3 bed-sharing groups, compared with the non-bed-sharing group. Higher maternal educational achievement and higher social class were positively associated with early bed sharing, negatively associated with late bed sharing, and not associated with constant bed sharing. The 3 bed-sharing patterns were related significantly to breastfeeding at 12 months (P < .001), whether the families shared beds late (odds ratio: 1.72 [95% confidence interval: 1.36-2.18]), early (odds ratio: 2.36 [95% confidence interval: 1.87-2.97]), or for the whole period (odds ratio: 5.29 [95% confidence interval: 4.05-6.91]). The prevalence of breastfeeding was significantly higher among the groups that shared beds constantly or early for each of the first 15 months after birth.

CONCLUSIONS

Advice on whether bed sharing should be discouraged needs to take into account the important relationship with breastfeeding.

The physiology of sleep in infants

Despite the fact that infants spend more time asleep than awake, an understanding of the importance and effects of sleep on the pathophysiology of illness in infancy is a relatively recent development, and is commonly overlooked in paediatric training. In this review we describe some of the characteristics of sleep in infancy, with particular reference to normal developmental physiology and its relevance to the signs, symptoms and pathophysiology of illness in this age group.

Head covering - a major modifiable risk factor for sudden infant death syndrome: a systematic review

BACKGROUND

Some victims of sudden infant death syndrome (SIDS) are found with their heads covered with bedclothes, but the significance of this is uncertain. The aim of this review is to describe the prevalence of head covering, the magnitude of the risk and how far the suggested causal mechanisms agree with current epidemiological evidence.

METHODS

Systematic review of population-based age-matched controlled studies.

RESULTS

Controlled observations of head covering for the final sleep were found in 10 studies. The pooled prevalence in SIDS victims was 24.6% (95% CI 22.3% to 27.1%) compared to 3.2% (95% CI 2.7% to 3.8%) among controls. The pooled univariate odds ratio (OR) was 9.6 (95% CI 7.9 to 11.7) and the pooled adjusted OR from studies mainly conducted after the fall in SIDS rate was 16.9 (95% CI 12.6 to 22.7). The risk varied in strength but was significant across all studies. In a quarter of cases and controls head covering had occurred at least once previously (pooled adjusted OR = 1.1; 95% CI 0.9 to 1.4). The population attributable risk (27.1%; 95% CI 24.7% to 29.4%) suggests avoiding head covering might reduce SIDS deaths by more than a quarter.

CONCLUSIONS

The epidemiological evidence does not fully support postulated causal mechanisms such as hypoxia, hypercapnoea and thermal stress, but neither does it support the idea that head covering is part of some terminal struggle. Head covering is a major modifiable risk factor associated with SIDS deaths and parental advice to avoid this situation should be emphasised.

Local search with quadratic approximations into memetic algorithms for optimization with multiple criteria

This paper proposes a local search optimizer that, employed as an additional operator in multiobjective evolutionary techniques, can help to find more precise estimates of the Pareto-optimal surface with a smaller cost of function evaluation. The new operator employs quadratic approximations of the objective functions and constraints, which are built using only the function samples already produced by the usual evolutionary algorithm function evaluations. The local search phase consists of solving the auxiliary multiobjective quadratic optimization problem defined from the quadratic approximations, scalarized via a goal attainment formulation using an LMI solver. As the determination of the new approximated solutions is performed without the need of any additional function evaluation, the proposed methodology is suitable for costly black-box optimization problems.

Sudden Infant Death Syndrome and the time of death: factors associated with night-time and day-time deaths

OBJECTIVE

To investigate the diurnal occurrence of Sudden Infant Death Syndrome (SIDS) and interaction with established risk factors in the infant sleeping environment.

METHODS

A 3 year population-based case-control study, in five English Health Regions. Parentally defined day-time or night-time deaths of 325 SIDS infants and reference sleep of 1300 age-matched controls.

RESULTS

The majority of SIDS deaths (83%) occurred during night-time sleep, although this was often after midnight and at least four SIDS deaths occurred during every hour of the day. The length of time from last observed alive until the discovery of death ranged from <l to 14 h but was not significantly different from the corresponding sleep period amongst the controls. Amongst the day-time deaths, 38% of the infants were observed alive 30 min prior to discovery and 9% within 10 min. The risk of placing infants asleep on their side was more marked for day-time deaths (interaction: P = 0.0001) nearly half of whom were found prone, while the risk associated with paternal smoking [OR = 3.25 (95%CI: 1.88-5.62)] was more marked for night-time deaths (interaction: P = 0.02). The adverse effect of unsupervised sleep recognized for night-time practice [OR = 5.38 (95%CI: 2.67-10.85)] was also significant for day-time sleep [OR = 10.57 (95%CI: 1.47-75.96)]. Significantly more (P = 0.002) unobserved SIDS infants (24.8%) were found with bedclothes over the head compared with those SIDS infants where a parent was present in the room (11.3%).

CONCLUSIONS

SIDS can happen at any time of the day and relatively quickly. Parents need to be made aware that placing infants supine and keeping them under supervision is equally important for day-time sleeps.

Sudden infant death syndrome and sleeping position in pre-term and low birth weight infants: an opportunity for targeted intervention

AIMS

To determine the combined effects of sudden infant death syndrome (SIDS) risk factors in the sleeping environment for infants who were "small at birth" (pre-term (<37 weeks), low birth weight (<2500 g), or both).

METHODS

A three year population based, case-control study in five former health regions in England (population 17.7 million) with 325 cases and 1300 controls. Parental interviews were carried out after each death and reference sleep of age matched controls.

RESULTS

Of the SIDS infants, 26% were "small at birth" compared to 8% of the controls. The most common sleeping position was supine, for both controls (69%) and those SIDS infants (48%) born at term or > or =2500 g, but for "small at birth" SIDS infants the commonest sleeping position was side (48%). The combined effect of the risk associated with being "small at birth" and factors in the infant sleeping environment remained multiplicative despite controlling for possible confounding in the multivariate model. This effect was more than multiplicative for those infants placed to sleep on their side or who shared the bed with parents who habitually smoked, while for those "small at birth" SIDS who slept in a room separate from the parents, the large combined effect showed evidence of a significant interaction. No excess risk was identified from bed sharing with non-smoking parents for infants born at term or birth weight > or =2500 g.

CONCLUSION

The combined effects of SIDS risk factors in the sleeping environment and being pre-term or low birth weight generate high risks for these infants. Their longer postnatal stay allows an opportunity to target parents and staff with risk reduction messages.

Major epidemiological changes in sudden infant death syndrome: a 20-year population-based study in the UK

BACKGROUND

Results of case-control studies in the past 5 years suggest that the epidemiology of sudden infant death syndrome (SIDS) has changed since the 1991 UK Back to Sleep campaign. The campaign's advice that parents put babies on their back to sleep led to a fall in death rates. We used a longitudinal dataset to assess these potential changes.

METHODS

Population-based data from home visits have been collected for 369 consecutive unexpected infant deaths (300 SIDS and 69 explained deaths) in Avon over 20 years (1984-2003). Data obtained between 1993 and 1996 from 1300 controls with a chosen "reference" sleep before interview have been used for comparison.

FINDINGS

Over the past 20 years, the proportion of children who died from SIDS while co-sleeping with their parents, has risen from 12% to 50% (p<0.0001), but the actual number of SIDS deaths in the parental bed has halved (p=0.01). The proportion seems to have increased partly because the Back to Sleep campaign led to fewer deaths in infants sleeping alone-rather than because of a rise in deaths of infants who bed-shared, and partly because of an increase in the number of deaths in infants sleeping with their parents on a sofa. The proportion of deaths in families from deprived socioeconomic backgrounds has risen from 47% to 74% (p=0.003), the prevalence of maternal smoking during pregnancy from 57% to 86% (p=0.0004), and the proportion of pre-term infants from 12% to 34% (p=0.0001). Although many SIDS infants come from large families, first-born infants are now the largest group. The age of infants who bed-share is significantly smaller than that before the campaign, and fewer are breastfed.

INTERPRETATION

Factors that contribute to SIDS have changed in their importance over the past 20 years. Although the reasons for the rise in deaths when a parent sleeps with their infant on a sofa are still unclear, we strongly recommend that parents avoid this sleeping environment. Most SIDS deaths now occur in deprived families. To better understand contributory factors and plan preventive measures we need control data from similarly deprived families, and particularly, infant sleep environments.

Sudden unexpected deaths after discharge from the neonatal intensive care unit

The published evidence on the risk of sudden unexpected death in infants after discharge from the neonatal intensive care unit (NICU) is reviewed, together with the relevance of the various identified potentially modifiable post-natal risk factors, particularly sleeping position. Infants of low birthweight, short gestation, and those with adverse perinatal histories are at substantially increased risk of sudden infant death syndrome (SIDS), but the potential benefits from following the measures designed to reduce the risk of SIDS are proportionally greater than for term infants. The use of home apnoea monitors has not been shown to be of value in preventing SIDS, but the importance of maintaining adequate oxygenation in infants with bronchopulmonary dysplasia is emphasised. Evidence based recommendations for care of infants after discharge from the NICU with a view to reducing the risk of SIDS are presented, and do not differ significantly from those for low-risk infants.

Sudden infant death syndrome and social deprivation: assessing epidemiological factors after post-matching for deprivation

As part of the confidential enquiry into stillbirths and deaths in infancy (CESDI), a 3-year population-based case-control study was specifically designed to look at risk factors associated with sudden infant death syndrome (SIDS) after the dramatic fall in incidence. The study was conducted between 1993 and 1996 in five English Health Regions (population 17 million) with parental interviews for each death and four age-matched controls. The aim of this analysis was to investigate the extent to which epidemiological characteristics associated with SIDS were particular to the syndrome or more general markers for socio-economic deprivation. One control was reassigned to each case post-matched for infant age, time of sleep and socio-economic status using components of the Townsend Deprivation Score. The post-matched analysis involved 323 SIDS infants and 323 controls with a similar socio-economic profile. Notable factors significant in the original univariable analysis that became non-significant after post-matching included young maternal age (median: 23 years 4 months SIDS vs. 23 years 11 months post-matched controls), being an unsupported mother (13.6% SIDS vs. 11.1% post-matched controls) and being bottle-fed (56.7% SIDS vs. 55.4% post-matched controls). Other factors, although clearly related to deprivation, such as parental smoking, remained significant in both the univariable and multivariable post-matched analyses.

Multiobjective optimization in quantitative structure-activity relationships: deriving accurate and interpretable QSARs

Deriving quantitative structure-activity relationship (QSAR) models that are accurate, reliable, and easily interpretable is a difficult task. In this study, two new methods have been developed that aim to find useful QSAR models that represent an appropriate balance between model accuracy and complexity. Both methods are based on genetic programming (GP). The first method, referred to as genetic QSAR (or GPQSAR), uses a penalty function to control model complexity. GPQSAR is designed to derive a single linear model that represents an appropriate balance between the variance and the number of descriptors selected for the model. The second method, referred to as multiobjective genetic QSAR (MoQSAR), is based on multiobjective GP and represents a new way of thinking of QSAR. Specifically, QSAR is considered as a multiobjective optimization problem that comprises a number of competitive objectives. Typical objectives include model fitting, the total number of terms, and the occurrence of nonlinear terms. MoQSAR results in a family of equivalent QSAR models where each QSAR represents a different tradeoff in the objectives. A practical consideration often overlooked in QSAR studies is the need for the model to promote an understanding of the biochemical response under investigation. To accomplish this, chemically intuitive descriptors are needed but do not always give rise to statistically robust models. This problem is addressed by the addition of a further objective, called chemical desirability, that aims to reward models that consist of descriptors that are easily interpretable by chemists. GPQSAR and MoQSAR have been tested on various data sets including the Selwood data set and two different solubility data sets. The study demonstrates that the MoQSAR method is able to find models that are at least as good as models derived using standard statistical approaches and also yields models that allow a medicinal chemist to trade statistical robustness for chemical interpretability.

Designing focused libraries using MoSELECT

When designing a combinatorial library it is usually desirable to optimise multiple properties of the library simultaneously and often the properties are in competition with one another. For example, a library that is designed to be focused around a given target molecule should ideally have minimum cost and also contain molecules that are bioavailable. In this paper, we describe the program MoSELECT for multiobjective library design that is based on a multiobjective genetic algorithm (MOGA). MoSELECT searches the product-space of a virtual combinatorial library to generate a family of equivalent solutions where each solution represents a combinatorial subset of the virtual library optimised over multiple objectives. The family of solutions allows the relationships between the objectives to be explored and thus enables the library designer to make an informed choice on an appropriate compromise solution. Experiments are reported where MoSELECT has been applied to the design of various focused libraries.

Combinatorial library design using a multiobjective genetic algorithm

Early results from screening combinatorial libraries have been disappointing with libraries either failing to deliver the improved hit rates that were expected or resulting in hits with characteristics that make them undesirable as lead compounds. Consequently, the focus in library design has shifted toward designing libraries that are optimized on multiple properties simultaneously, for example, diversity and "druglike" physicochemical properties. Here we describe the program MoSELECT that is based on a multiobjective genetic algorithm and which is able to suggest a family of solutions to multiobjective library design where all the solutions are equally valid and each represents a different compromise between the objectives. MoSELECT also allows the relationships between the different objectives to be explored with competing objectives easily identified. The library designer can then make an informed choice on which solution(s) to explore. Various performance characteristics of MoSELECT are reported based on a number of different combinatorial libraries.