Environment of infants during sleep and risk of the sudden infant death syndrome: results of 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy. Confidential Enquiry into Stillbirths and Deaths Regional Coordinators and Researchers

Inspired CO(2) and O(2) in sleeping infants rebreathing from bedding: relevance for sudden infant death syndrome

Some infants sleep facedown for long periods with no ill effects, whereas others become hypoxemic. Rebreathing of expired air has been determined by CO(2) measurement; however, O(2) levels under such conditions have not been determined. To evaluate this and other factors influencing inspired gas concentrations, we studied 21 healthy infants during natural sleep while facedown on soft bedding. We measured gas exchange with the environment and bedding, ventilatory response to rebreathing, and concentrations of inspired CO(2) and O(2). Two important factors influencing inspired gas concentrations were 1) a variable seal between bedding and infants' faces and 2) gas gradients in the bedding beneath the infants, with O(2)-poor and CO(2)-rich air nearest to the face, fresher air distal to the face, and larger tidal volumes being associated with fresher inspired air. Minute ventilation increased significantly while rebreathing because of an increase in tidal volume, not frequency. The measured drop in inspired O(2) was significantly greater than the accompanying rise in inspired CO(2). This appears to be due to effects of the respiratory exchange ratio and differential tissue solubilities of CO(2) and O(2) during unsteady conditions.

Maternal awareness of sudden infant death syndrome in North Queensland, Australia: an analysis of infant care practices

OBJECTIVES

To assess awareness of sudden infant death syndrome (SIDS) and risk reducing recommendations in a sample of mothers in North Queensland, Australia, and to examine their infant care practices.

METHOD

Interviews conducted with 195 women using a standardized questionnaire between October 1997 and January 1998.

RESULTS

191 questionnaires analyzed; 134 (70.2%) Caucasian and 57 (29.8%) indigenous women. Four women with previous SIDS experience were excluded from the analysis. Eight (4.2%) had never heard of SIDS. Twenty-nine (15.2%) had heard of SIDS and 154 (80.6%) had heard of SIDS and could list risk recommendations to reduce its incidence. Multivariate analysis identified ethnicity as the only significant predictor of maternal knowledge. Indigenous mothers knew less about SIDS: adjusted odds ratio (OR) = 5.4; 95% confidence interval (CI) = [2.1-14.0]. Avoidance of prone sleeping was the most frequently identified recommendation (n = 132), with no smoking in pregnancy (n = 48) and breastfeeding (n = 40) identified least frequently. There were 80.2% of mothers who put their infant in non-prone positions to sleep. Only 48 (25%) women identified smoking in pregnancy, and 93 (48.6%) smoking in the infant's environment as risk factors. Indigenous women were more likely to smoke in their pregnancy (P = 0.004), bed share with their infant (P = 0.0001), and have smokers in the home.

CONCLUSION

There is a high level of awareness of SIDS and the main associated risk factor of infant prone sleeping, but the link between SIDS and smoking requires further emphasis. Future campaigns should ensure the SIDS message is delivered more effectively to the indigenous communities.

Association between sudden infant death syndrome and prone sleep position, bed sharing, and sleeping outside an infant crib in Alaska

OBJECTIVE

To determine the contribution of prone sleeping, bed sharing, and sleeping outside an infant crib to sudden infant death syndrome (SIDS).

METHODS

We conducted a retrospective descriptive study of all SIDS cases in Alaska from January 1, 1992, through December 31, 1997. Reviewed data sources included maternal and infant medical records, autopsy reports, birth and death certificates, police and state trooper death scene investigations, and occasionally home interviews.

RESULTS

The death certificate identified SIDS as a cause of death for 130 infants (cause-specific infant mortality rate: 2.0 per 1000 live births). Among infants for whom this information was known, 113 (98%) of 115 were found in the prone position, sleeping outside an infant crib, or sleeping with another person. By contrast, 2 (1.7%) were found alone and supine in their crib (1 of whom was found with a blanket wrapped around his face). Of 40 infants who slept with a parent at the time of death, only 1 infant who slept supine with a non-drug-using parent on an adult nonwater mattress was identified.

CONCLUSION

Almost all SIDS deaths in Alaska occurred in association with prone sleeping, bed sharing, or sleeping outside a crib. In the absence of other risk factors, SIDS deaths associated with parental bed sharing were rare.

Changes in the epidemiological pattern of sudden infant death syndrome in southeast Norway, 1984-1998: implications for future prevention and research

AIM

To look for changes in risk factors for sudden infant death syndrome (SIDS) after decrease and stabilisation of the SIDS rate.

METHODS

Questionnaires were distributed to parents of 174 SIDS infants, dying between 1984 and 1998, and 375 age and sex matched controls in southeast Norway.

RESULTS

The proportion of infants sleeping prone has decreased, along with the decrease in SIDS rate for the region during the periods studied, but over half of the SIDS victims are still found in the prone position. As the number of SIDS cases has decreased, additional risk factors have become more significant. Thus, after 1993, a significantly increased risk of SIDS is seen when the mother smokes during pregnancy. After 1993, young maternal age carries an increased risk. Maternal smoking and young maternal age are associated with each other. For SIDS victims, an increase in the number of infants found dead while co-sleeping is seen, and the age peak between 2 and 4 months and the winter peak have become less pronounced.

CONCLUSION

Changes in risk factor profile following the decrease in SIDS rate in the early 1990s, as well as consistency of other factors, provides further clues to SIDS prevention and to the direction of further studies of death mechanisms.

Assessment of dry heat exchanges in newborns: influence of body position and clothing in SIDS

A dramatic decrease of sudden infant death syndrome (SIDS) has been noted following the issuance of recommendations to adopt the supine sleeping position for infants. It has been suggested that the increased risk could be related to heat stress associated with body position. In the present study, the dry heat losses of small-for-gestational-age newborns nude or clothed were assessed and compared to see whether there is a difference in the ability to lose heat between the prone and supine positions. An anthropomorphic thermal mannequin was exposed to six environmental temperatures, ranging between 25 and 37 degrees C, in a single-walled, air-heated incubator. The magnitudes of heat losses did not significantly differ between the two body positions for the nude (supine 103.46 +/- 29.67 vs. prone 85.78 +/- 34.91 W/m(2)) and clothed mannequin (supine 59.35 +/- 21.51 vs. prone 63.17 +/- 23.06 W/m(2)). With regard to dry heat exchanges recorded under steady-state conditions, the results show that there is no association between body position and body overheating.

Review of risk factors for sudden infant death syndrome

Sudden infant death syndrome (SIDS) accounts for the largest number of deaths during the first year of life in developed countries. The possible causes of SIDS are numerous and, to date, there is no adequate unifying pathological explanation for SIDS. Epidemiological studies have played a key role in identifying risk factors, knowledge of which has underpinned successful preventive programmes. This review critically assesses information on the main risk factors and causal hypotheses put forward for SIDS, focusing on research published since 1994. The overall picture that emerges from this review is that affected infants are not completely normal in development, but possess some inherent weakness, which may only become obvious when the infant is subjected to stress. Initially there may be some minor impairment or delay in development of respiratory, cardiovascular or neuromuscular function. None of these is likely to be sufficient, in isolation, to cause death and, provided the infant survives the first year of life, may no longer be of any significance. However, when a compromised infant is confronted with one or more stressful situations, several of which are now clearly identified as risk factors, and from which the majority of infants would normally escape, the combination may prove fatal.

Thermal stress in sudden infant death: Is there an ambiguity with the rebreathing hypothesis?

OBJECTIVE

To assess the role of thermal stress in the cause of sudden infant death syndrome (SIDS), and to compare risk factors with those of rebreathing.

METHODOLOGY

Analysis of publications concerning the epidemiology and physiology of thermal stress in SIDS.

RESULTS

A strong association between thermal regulation and ventilatory control was found, specifically for prolonged apnea. Infections, excessive room heat and insulation, and prone sleeping produce significantly increased odds ratios for SIDS. Although some of the risk factors for rebreathing could be explained by the effects of thermal stress, several factors for thermal stress could not reasonably be explained by the rebreathing hypothesis.

CONCLUSIONS

Although the risk of thermal stress is widely accepted abroad, it has received relatively little attention in the United States. The incidence of SIDS in the United States can likely be further reduced by educating the public against the dangers of overheating, as an integral part of the back-to-sleep campaign.

Sleep position and the use of soft bedding during bed sharing among African American infants at increased risk for sudden infant death syndrome

Soft bedding increases the risk for death among prone infants. We compared the softness of beds and bedding and infant sleep position for infants sleeping alone and for those bed sharing.

STUDY DESIGN

Questionnaires were used to record the bedding and sleep practices of 218 consecutive African American infants. Enrollment was prospective. Mechanical models were used in the homes of a subgroup to measure the softness of bedding and its propensity to cause rebreathing. Results were compared by using the Student t test, Mann-Whitney U test, and chi(2) analysis.

RESULTS

In a cross-sectional sample of infants, at 8.2 +/- 3.3 weeks of age, 61% (133 of 218) had bed shared > or =1 of the previous 14 nights and 48.6% (106 of 218) had bed shared the night before. Breast-feeding rates were not different for bed sharers and those sleeping alone. The rates of maternal smoking for both groups were low (13.6% vs 11.8%). Comforters, pillows, and waterbeds were more commonly used beneath bed-sharing infants. Bed sharers were twice as likely to habitually be placed prone for sleep (18% vs 9%). In the subgroup studied in their homes (13 bed sharing, 19 alone), the shared beds were softer (P <.0001) and could cause more rebreathing (P =.007).

CONCLUSIONS

Infants at increased risk for sudden infant death syndrome, by sociodemographic criteria, who also bed share are more likely to sleep prone and to use softer beds. These findings may explain part of the risk associated with bed sharing among US infants, a risk that appears to be independent of the effects of maternal smoking.

Simultaneous sudden infant death syndrome: a proposed definition and worldwide review of cases

Epidemiologic studies of sudden infant death syndrome (SIDS), the leading cause of death of infants during the postperinatal period (7-365 days), have mainly focused on the deaths of single infants. Simultaneous sudden infant death syndrome (SSIDS), the death of a pair of twins occurring at the same time, has received limited attention within the medical community. To the authors' knowledge, this article is the first to describe the 41 SSIDS cases cited in the world literature from 1900 to 1998 by the location of death, a summary of the circumstances surrounding the deaths, and evaluation of these cases in terms of a proposed definition of SSIDS. This evaluation critiques whether the 41 pairs of SSIDS cases adhere to a newly proposed definition of SSIDS. Twin infant deaths must meet all three criteria to be considered SSIDS. The study found that only 12 pairs of twins met all three criteria (29.2%), nine pairs met two criteria (21.9%), alternative cause of death was offered in five pairs of twins (12.1%) and in the remaining 15 pairs (36.6%), only limited information was available; therefore, no conclusions could be reached.

Factors that influence passive smoking in infancy: a study among mothers of newborn babies in The Netherlands

BACKGROUND

The aim of this study was to assess the factors that influence smoking in the presence of the infant by mothers, partners, other family members, and friends.

METHODS

An observational study using questionnaires was performed with smoking and nonsmoking parents of babies between 1 and 14 months old attending Dutch well-baby clinics between February and May 1996. The main measures were prevention of passive smoking in children by mothers and the relation with self-reported attitudes, social influence, and self-efficacy.

RESULTS

A total of 1702 parents completed the questionnaire (63%). A total of 1551 questionnaires were completed by the mother. Sixty-five percent of the mothers prevented passive smoking by their child. This figure was 55% for smokers and 69% for nonsmokers. Attitude was the factor that most explained preventive behavior among both smokers and nonsmokers. Among the respondents, a lack of prevention of passive smoking was significantly related to (1) a negative attitude and 2) a negative social influence exerted by their partner, (3) lower self-efficacy in reducing passive smoking, and (4) increasing age of the child. (5) Finally, a lack of prevention is associated with the mother's self-efficacy in asking others not to smoke. This association strongly differs between smoking and nonsmoking mothers.

CONCLUSION

The results suggest that health education efforts should focus on attitude and self-efficacy, assuming that these precede actual behavior, and in particular on the health consequences of the exposure of young children to tobacco smoke. The information should not be restricted to parents of newborn babies; it should also focus on parents with older children. Particular attention should be paid to smokers with a low educational level. The results also indicate that education should strengthen the ability of nonsmoking parents to deal with smokers and the ability of smoking parents to deal with their own smoking behavior.

Effect of sleep position on apnea and bradycardia in high-risk infants

OBJECTIVE

The purpose of this investigation was to investigate, in high-risk infants, the occurrence of abnormalities in documented monitor downloads during the side versus prone position.

STUDY DESIGN

Forty infants admitted to the A. I. duPont Hospital for Children with diagnoses associated with sudden infant death syndrome were included in this investigation. During an overnight hospitalization, infants were placed on home apnea monitors, with computer memory to capture alarms for apnea > 20 seconds, age-defined bradycardia, and tachycardia. Infants were studied for 12 hours. Each infant was assigned to 6 hours of prone and side during the 12-hour period, with order of position randomly assigned by random number generation. Differences between the two positions in alarm frequency and significant events, as determined by a blinded interpreting physician were analyzed by Fisher exact test, with p < 0.05. Power analysis necessitated 20 patients in each group, with beta error of 0.2.

RESULTS

Eleven episodes of apnea occurred in the prone position, and 16 in the side position (p = NS). The mean numbers of apnea events per tracing in the prone position was 0.27 +/- 0.84 and 0.39 +/- 1.1 in the side position (p = 0.58). The mean number of bradycardia events per tracing in the prone position was 0.44 +/- 1.45 and 0.49 +/- 1.94 in the side position (p = 0.9).

CONCLUSION

Clinicians need to be cautious when recommending the side or prone position in this group of high-risk infants. The results in this investigation provide support for the Back to Sleep Campaign recommendations to be applied, not only to healthy term infants, but higher risk infants as well. Studies of the high-risk infant in the supine position are warranted.

Sleep position and bed-sharing in sudden infant deaths: an examination of autopsy findings

OBJECTIVE

To determine the effect of sleep position, sleep location, and bed-sharing on the incidence of sudden unexpected death in infancy and the frequency of significant autopsy findings.

METHODS

We evaluated the cause of death in infants <1 year of age who died during sleep from January 1, 1986, through September 30, 1999. This retrospective series was compiled from log books and files of the Medical Examiner Office, Palm Beach County, Florida.

RESULTS

The incidence of sudden unexpected infant death decreased 50% over the study period (P <.01). Of the 217 infants that fit the study criteria, 62.7% were sleeping prone (on the stomach), 9.7% were supine (on the back), 5.5% were on their side, 22.1% were in an unknown position, and 40.1% were bed-sharing. Significant autopsy findings that could explain death were documented by autopsy in 37.5% of all supine and side sleeping infants and only 14.0% of all prone sleeping infants (P <.001). Deaths of supine and side sleeping infants were more likely to be classified as a natural disease process other than sudden infant death syndrome (P <.01). Significant autopsy findings that could explain death were found in 47.6% of the infants sleeping alone in the supine or side position (P <.01), 18.2% of infants bed-sharing in the supine or side position, 16.5% of infants sleeping alone while prone, and 9.3% of infants bed-sharing while prone.

CONCLUSIONS

Infant deaths associated with the prone position were less frequently explained by illness or disease than infant deaths associated with non-prone sleeping positions. Bed-sharing appears to increase the proportion of unexplained deaths, regardless of the position of the infant. The "Back to Sleep" campaign appears to be effective in reducing the incidence of unexpected sleeping infant deaths regardless of the certified cause of death.

[Mothers' behavior regarding infant sleep position: effects of the last public campaign to prevent sudden infant death syndrome]

BACKGROUND

To define infant care practices in maternity units and those subsequently adopted at home. Using these data, we evaluated the acceptance and application of recommendations issued by the previous public education campaign on infant sleeping position as related to sudden infant death syndrome.

PATIENTS AND METHODS

A survey was carried out in two maternity units (Port-Royal and Créteil) and in one pediatric consultation unit (affiliated with Port-Royal maternity).

RESULTS

The mixed position (side or back) is used equally with, respectively, 47% at Port-Royal and 45% at Créteil. The supine sleeping position (French public health recommendations) is used by 12% of the mothers at Port-Royal and by 40% at Créteil. It appears that hospital nurseries play an important role in determining the mother's preference for the sleeping position (64% at Port-Royal and 54% at Créteil), but it does not adequately explain all mothers' responses. However, as the infants mature (> two months old), the more spontaneously they changed their sleeping position. All the infants placed in a side sleeping position moved to a supine sleeping position during the night. Upon awakening, infants were found mostly in the supine position (in contrast to the national public education campaign).

CONCLUSION

Our results show that mothers and hospital nurseries were distressed in terms of ensuring the supine sleeping position of the infant. New choices of sleeping positions were initiated by mothers. For example, they used the side position after feedings essentially in the case of reflux or during the daytime. The supine position was used when the mothers were assured that any problems had been avoided or only during the night.

CLINICAL REVIEW ARTICLE: Is changing the sleep environment enough? Current recommendations for SIDS

Sudden infant death syndrome (SIDS or cot death) was the major cause of post-neonatal infant death in many countries in the late 1970s and 1980s. There is now very strong evidence that public intervention campaigns targeting the prone sleeping position, which had been identified by epidemiological studies as a major risk factor, were followed by substantial falls in the rate of SIDS. In the present review we discuss the evidence on which current recommendations for the prevention of SIDS are based. The prone sleeping position is now clearly causally associated with SIDS. Further reductions in SIDS may be produced by recommending the back sleeping position as opposed to the side position. Maternal smoking in pregnancy and bed sharing by infants of mothers who smoke are also strongly associated with SIDS, but have been harder to influence. Paternal smoking has also been implicated, although the magnitude of the reported risk is small. Finally, breastfeeding, pacifier use and having the infant sharing the parents bedroom, but not the bed, may also reduce risk. Continued reductions in SIDS mortality will require innovative public health education to target these major risk factors, while building on the "back to sleep" approach.

Infant oral health and oral habits

Many oral diseases and conditions, including dental caries (cavities) and malocclusions, have their origins early in life. Prudent anticipatory guidance by the medical and dental professions can help prevent many of the more common oral health problems. This article provides information on the rationale for early dental examination and instructions for pediatric and family practitioners in scheduling and conducting an early oral intervention appointment. In addition, feeding practices, non-nutritive sucking, mouth breathing, and bruxing are discussed, including their effects on orofacial growth and development.

Visualization of sleep influences on cerebellar and brainstem cardiac and respiratory control mechanisms

Cerebellar and vestibular structures exert substantial influences on breathing and cardiovascular activity, particularly under conditions of extreme challenges. Influences from these structures, as well as from the ventral medullary surface, are greatly modified during sleep states. Vestibular lesions abolish the pronounced phasic autonomic variation found in the rapid eye movement sleep state, and spontaneous ventral medullary surface activity, as assessed by optical procedures, is greatly diminished in that state. Neural responses from the ventral medullary surface to hypotensive challenges are enhanced and appear "undampened" during the rapid eye movement sleep state. Functional magnetic resonance imaging reveals activation to blood pressure challenges in widespread brain areas of humans, and especially in cerebellar sites, such as the fastigial nucleus. A subset of victims of sudden infant death syndrome, a sleep-related disorder, appear to succumb from cardiovascular failure of a shock-like nature, and often show neurotransmitter receptor deficiencies in the ventral medullary surface, caudal midline raphe hypotensive regions, and the inferior olive, a major afferent relay to the cerebellum. Afferent and efferent vestibular/cerebellar structures, or sites within the cerebellum may mediate failure mechanisms in sudden infant death syndrome and a number of other sleep-disordered breathing and cardiovascular syndromes.

The healthy human infant tends to sleep in the prone rather than the supine position

There are few reports about developmental behavior relating to roll over among healthy infants. We assessed the relationship between the placed position on sleeping and altered sleeping position the next morning by roll over among healthy infants. A health check-up clinic distributed a total of 1626 questionnaires to parents whose infant's ages are 1.5 years (or 18 months) old. The age at the first roll over and the change in sleeping position the next morning after they started to roll over, were investigated. The mean age of roll over from the supine to the prone among infants who were placed mainly in the prone sleeping position, at least in the first week of life, was 4.0 months (S.D., 1.1). The mean age of roll over from the supine to the prone among infants who were placed mainly in the supine sleeping position during early neonatal life and thereafter was 4.4 months (S.D., 1.2). The age of the first roll over from supine to prone was significantly younger in infants who were placed mainly in the prone sleeping position during early neonatal life. Among 651 infants who had been placed supine, 34.7% were found prone by roll over the next morning. Among 211 infants who had been placed prone, 14.2% were found supine by roll over the next morning. The number of infants who rolled over from supine to prone position was statistically greater than those from prone to supine. It is likely that the healthy human infant tends to sleep in the prone rather than the supine position. The finding is especially important for the correct assessment of the position in which SIDS cases were found dead.

Computerised audiovisual event recording for infant apnoea and bradycardia

Event recording, by differentiating between true and false events, has advanced the diagnosis and management of infants on home cardiorespiratory monitors; however, the pathogenesis of many events remains obscure. To clarify infant behaviours around the time of apnoea/bradycardia alarms, a computerised audiovisual event recording system (CAVERS) triggered by the apnoea/bradycardia recorder, has been developed. The audiovisual recording can begin up to 3 min before the alarm and can continue for up to 3 min after the alarm. CAVERS information is recorded for a total of 65 events in 13 infants. The CAVERS proves most helpful in documenting infant position and the wide variety of behaviours associated with bradycardic events. These behaviours range from sleep or quiet wakefulness to crying and generalised movements. Post-event activity is also highly variable. Interestingly, 20 of 65 events appear to terminate when the infant wakes to the audible monitor alarm. Nursing intervention is documented for 14 of 42 bradycardic events but only one of 23 apnoeic events. The CAVERS, by elucidating infant behaviours, provides information complementary to that given by cardiorespiratory event recording. It is suggested that infant monitors of the future should incorporate both audiovisual and cardiorespiratory data to elucidate optimally apparent life-threatening events, apnoeas and bradycardias.

Unsafe sleep practices and an analysis of bedsharing among infants dying suddenly and unexpectedly: results of a four-year, population-based, death-scene investigation study of sudden infant death syndrome and related deaths

BACKGROUND

Prone sleep and unsafe sleep surfaces increase the risk of sudden infant death. Recent epidemiologic studies also suggest that when an infant's head or face is covered by bedding, or when a sleep surface is shared with others, the risk of dying increases. The inference of a causal role for these risk factors is supported by physiologic studies and by the consistent finding that fewer infants die when risk factors are reduced. The prevalence of most of these risk factors in infant deaths in the United States is uncertain.

OBJECTIVE

To describe the prevalence of several important risk factors related to sleep practices among a defined population of infants dying suddenly and unexpectedly.

METHODS

In this population-based study, we retrospectively reviewed death-scene information and medical examiners' investigations of deaths in the city of St Louis and St Louis County between January 1, 1994 and December 31, 1997. Because of the potential for diagnostic overlap, all deaths involving infants <2 years old with the diagnoses of sudden infant death syndrome (SIDS), accidental suffocation, or cause undetermined were included.

RESULTS

The deaths of 119 infants were studied. Their mean age was 109.3 days (range: 6-350). The diagnoses were SIDS in 88 deaths, accidental suffocation in 16, and undetermined in 15. Infants were found prone in 61.1% of cases and were found on a sleep surface not designed for infants in 75.9%. The head or face was covered by bedding in 29.4%. A shared sleep surface was the site of death in 47.1%. Only 8.4% of deaths involved infants found nonprone and alone, with head and face uncovered.

CONCLUSIONS

Using detailed death-scene descriptions, we found that similar unsafe sleeping practices occurred in the large majority of cases diagnosed as SIDS, accidental suffocation, and cause undetermined. Considering these diagnoses together may be useful in public health campaigns during a time when there may be diagnostic overlap. Regardless of the diagnosis, recommendations that infants sleep supine on firm sleep surfaces that lessen the risk of entrapment or head covering have the potential to save many lives. Campaigns are needed to heighten awareness of these messages and of the risks of dangerous bedsharing.

Cree infant care practices and sudden infant death syndrome

OBJECTIVE

To identify contemporary Cree infant care practices and any risk factors associated with Sudden Infant Death Syndrome.

METHODS

A questionnaire conducted and recorded in the homes of 70 Cree women (83% of sample available) with infants under 12 months of age, living full time on a Cree reserve. Participatory observation was also used with mothers who agreed to demonstrate certain features of Cree infant care.

FINDINGS

70% of mothers initiated breast-feeding and 43% nursed from 6 to 15 months. Cree infants are tightly swaddled and placed in a supine position for sleeping. Prenatal care is seldom utilized because of cultural beliefs that planning ahead constitutes bad luck during birth or results in deformed infants.

CONCLUSIONS

Existing infant care practices include several that are considered protective to an infant in terms of reducing vulnerability to SIDS. Swaddling infants in very warm houses and smoking during pregnancy could contribute to a higher SIDS incidence.

Weight gain and sudden infant death syndrome: changes in weight z scores may identify infants at increased risk

AIMS

To investigate patterns of infant growth that may influence the risk of sudden infant death syndrome (SIDS).

DESIGN

Three year population based case control study with parental interviews for each death and four age matched controls. Growth was measured from prospective weight observations using the British 1990 Growth Reference.

SETTING

Five regions in England (population greater than 17 million, more than 470 000 live births over three years).

SUBJECTS

247 SIDS cases and 1110 controls.

RESULTS

The growth rate from birth to the final weight observation was significantly poorer among the SIDS infants despite controlling for potential confounders (SIDS mean change in weight z score (deltazw) = -0.38 (SD 1.40) v controls = +0.22 (SD 1.10), multivariate: p < 0.0001). Weight gain was poorer among SIDS infants with a normal birth weight (above the 16th centile: odds ratio (OR) = 1.75, 95% confidence interval (CI) 1. 48-2.07, p < 0.0001) than for those with lower birth weight (OR = 1. 09, 95% CI 0.61-1.95, p = 0.76). There was no evidence of increased growth retardation before death.

CONCLUSIONS

Poor postnatal weight gain was independently associated with an increased risk of SIDS and could be identified at the routine six week assessment.

Bed sharing patterns in a cohort of Australian infants during the first six months after birth

OBJECTIVE

To measure bed sharing (BS) activity in healthy term infants.

METHODOLOGY

The sleep-wake behaviour and place of infant sleep were recorded for infants aged between 2 and 24 weeks. Infants were then identified as BS or non bed sharing (NBS) according to each of four different definitions of bed sharing.

RESULTS

The mean proportion of infants who spent any time BS during a 24-h period was significantly greater (P < 0.05) between 2 and 12 weeks (40.9 +/- 1. 4%) than between 13 and 24 weeks (36.5 +/- 1.5%). A significantly greater proportion (P < 0.005) of infants bed shared for more than 2 h (25 +/- 1%) than for either 1-2 h (10.5 +/- 1.1%) or for less than 1 h/24 h (3.2 +/- 0.5%) during the whole study period. Each of the definitions of BS used in the study separated infants on the basis of the amount and frequency of BS activity.

CONCLUSION

: Bed sharing activity was common and varied in this cohort. It was possible, using quantitative definitions, to identify those infants who routinely bed share.

Cree infant care practices and sudden infant death syndrome

OBJECTIVE

To identify contemporary Cree infant care practices and any risk factors associated with Sudden Infant Death Syndrome.

METHODS

A questionnaire conducted and recorded in the homes of 70 Cree women (83% of sample available) with infants under 12 months of age, living full time on a Cree reserve. Participatory observation was also used with mothers who agreed to demonstrate certain features of Cree infant care.

FINDINGS

70% of mothers initiated breast-feeding and 43% nursed from 6 to 15 months. Cree infants are tightly swaddled and placed in a supine position for sleeping. Prenatal care is seldom utilized because of cultural beliefs that planning ahead constitutes bad luck during birth or results in deformed infants.

CONCLUSIONS

Existing infant care practices include several that are considered protective to an infant in terms of reducing vulnerability to SIDS. Swaddling infants in very warm houses and smoking during pregnancy could contribute to a higher SIDS incidence.

Changing concepts of sudden infant death syndrome: implications for infant sleeping environment and sleep position. American Academy of Pediatrics. Task Force on Infant Sleep Position and Sudden Infant Death Syndrome

The American Academy of Pediatrics has recommended since 1992 that infants be placed to sleep on their backs to reduce the risk of sudden infant death syndrome (SIDS). Since that time, the frequency of prone sleeping has decreased from >70% to approximately 20% of US infants, and the SIDS rate has decreased by >40%. However, SIDS remains the highest cause of infant death beyond the neonatal period, and there are still several potentially modifiable risk factors. Although some of these factors have been known for many years (eg, maternal smoking), the importance of other hazards, such as soft bedding and covered airways, has been demonstrated only recently. The present statement is intended to review the evidence about prone sleeping and other risk factors and to make recommendations about strategies that may be effective for further reducing the risk of SIDS. This statement is intended to consolidate and supplant previous statements made by this Task Force.

Effect of prone sleeping on circulatory control in infants

BACKGROUND

The mechanism of death in sudden infant death syndrome (SIDS) remains unclear. Progressive bradycardia is the pre-eminent terminal event, suggesting that circulatory failure might be a crucial factor. Vasomotor tone regulates the circulatory system by controlling blood volume distribution while maintaining venous return and blood pressure.

AIM

To examine whether prone sleeping, the most consistently identified risk factor for SIDS, has a measurable influence on vasomotor/circulatory control.

METHODS

44 full term infants (mean age, 7.9 weeks) were studied during an overnight sleep. Recordings were made while the infants were horizontal and asleep in the supine and prone positions, and repeated after a head up tilt to 60 degrees, maintained for 30 minutes, while in both sleep positions. Blood pressure, heart rate, anterior shin, and anterior abdominal wall skin temperatures were measured.

RESULTS

Systolic blood pressure was lower, but peripheral skin temperature and heart rate were higher during sleep, while horizontal, in the prone rather than the supine position. After tilting, there was a greater reduction in blood pressure and a greater increase in peripheral skin temperature and heart rate when in the prone position. Anterior abdominal wall skin temperature did not vary in either sleeping positions while horizontal or tilted.

CONCLUSION

Prone sleeping has a measurable effect on circulatory control, with a reduction in vasomotor tone resulting in peripheral vasodilatation, a higher peripheral skin temperature, a lower blood pressure, and a higher resting heart rate. Because vasomotor tone is crucially important in circulatory control this could be a factor in increasing the risk of SIDS.

Sleep influences on homeostatic functions: implications for sudden infant death syndrome

The mechanisms underlying the sudden infant death syndrome (SIDS) appear to have origins in the fetal environment resulting in neural damage which later compromises responses to breathing or blood pressure challenges during sleep. The deficits appear to involve alterations in neurotransmitter receptors within regions involved in chemoreception and cardiovascular control. SIDS risk is enhanced by pre- and postnatal nicotine exposure, and possibly by hypoxic experiences. The prone sleeping position plays a significant role in risk, as do head positions that minimize facial escape from enclosed spaces; elevated body temperature may also be a factor. Compensatory mechanisms, including diminished gasping ability, relative failure to arouse to a safer state, or a failure to recruit respiratory efforts to overcome a blood pressure loss have been the object of recent research efforts. The findings suggest that the fatal event involves a neurally-compromised infant, circumstances that challenge vital physiology, most likely during sleep, at a particular developmental period.

The role of breastfeeding in sudden infant death syndrome

The objective of this article is to review the literature regarding the risk of sudden infant death syndrome (SIDS) in bottle-fed infants compared to those that are breastfed. A meta-analysis and qualitative literature review were performed. Cohort and case-control studies were included if they met a minimum SIDS definition and presented data allowing calculation of an odds ratio (OR). Twenty-three studies were included in the meta-analysis. The studies were heterogeneous, and a majority (14) were of "fair" or "poor" quality. Crude ORs from 19 individual studies favored breastfeeding as protective against SIDS. The combined analysis indicated that bottle-fed infants were twice as likely to die from SIDS (pooled OR = 2.11; 95% CI 1.66-2.68). The results of the analysis show that there is an association between bottle-feeding and SIDS, but this may be related to confounding variables.

Sudden infant death syndrome--are parents getting the message?

BACKGROUND

Factors that place an infant at increased risk of sudden infant death include the prone sleep position, overheating and parental smoking, while practices such as bottle-feeding, co-sleeping and the use of pacifiers remain controversial. Major publicity campaigns have been undertaken, which have included the distribution of printed material and extensive media coverage.

AIMS

To examine if Irish parents follow the currently recommended childcare guidelines to reduce the risk of sudden infant death and to examine factors that may have impact on their acceptance.

METHODS

A random selection of 197 infants from the Birth Register of the Eastern Health Board. Parents were interviewed and a semi-structured survey questionnaire was completed.

RESULTS

Forty one per cent of infants are still placed on their side to sleep, an inherently unstable position. First time parents are more likely to place their infants on their backs. Over 60% of infants are exposed to one or more adults smoking in the home despite parental knowledge of its association with sudden infant death syndrome (SIDS). Sixty eight per cent of infants are overwrapped at night and parental understanding of what constitutes overwrapping is poor. Thirteen per cent of infants regularly co-sleep with their parents and 20% of these parents smoke. Pacifier use is common.

CONCLUSION

Future programmes should target first time parents, should provide clear information regarding appropriate infant thermal environment, and should ensure regular updating of medical personnel so that they can instruct families on best current practice. Smoking remains a significant health issue with an impact on sudden infant death.

Babies sleeping with parents: case-control study of factors influencing the risk of the sudden infant death syndrome. CESDI SUDI research group

OBJECTIVE

To investigate the risks of the sudden infant death syndrome and factors that may contribute to unsafe sleeping environments.

DESIGN

Three year, population based case-control study. Parental interviews were conducted for each sudden infant death and for four controls matched for age, locality, and time of sleep.

SETTING

Five regions in England with a total population of over 17 million people.

SUBJECTS

325 babies who died and 1300 control infants.

RESULTS

In the multivariate analysis infants who shared their parents' bed and were then put back in their own cot had no increased risk (odds ratio 0.67; 95% confidence interval 0.22 to 2.00). There was an increased risk for infants who shared the bed for the whole sleep or were taken to and found in the parental bed (9.78; 4.02 to 23.83), infants who slept in a separate room from their parents (10.49; 4.26 to 25.81), and infants who shared a sofa (48.99; 5.04 to 475.60). The risk associated with being found in the parental bed was not significant for older infants (>14 weeks) or for infants of parents who did not smoke and became non-significant after adjustment for recent maternal alcohol consumption (>2 units), use of duvets (>4 togs), parental tiredness (infant slept </=4 hours for longest sleep in previous 24 hours), and overcrowded housing conditions (>2 people per room of the house).

CONCLUSIONS

There are certain circumstances when bed sharing should be avoided, particularly for infants under four months old. Parents sleeping on a sofa with infants should always be avoided. There is no evidence that bed sharing is hazardous for infants of parents who do not smoke.

Night-time non-nutritive sucking in infants aged 1 to 5 months: relationship with infant state, breastfeeding, and bed-sharing versus room-sharing

AIM

Epidemiological studies suggest that pacifier use may be protective against SIDS but little is known of the relationship between pacifier use and other forms of non-nutritive sucking (NNS) in infancy, or of patterns of NNS during the night, when most SIDS deaths occur. We report the first longitudinal study of NNS by direct overnight observations in healthy infants in a sleep laboratory.

METHODS

Healthy, breast fed term infants (n = 10) were enrolled at birth, and sequential overnight polygraphic and infrared video recordings of infants with their mothers performed at monthly intervals from 1 to 5 months. Each month, mother baby pairs were randomized to 1 night bed-sharing (BN) then 1 room-sharing (RN), or vice versa. 'Episodes' of pacifier, own digit and mother's digit sucking (> 1 min) were identified and compared with state-matched control periods without sucking or feeding before and after each such episode.

RESULTS

329 episodes of NNS were identified in 749 h of video recording. The prevalence of pacifier sucking decreased with age, whilst digit sucking increased. Routine pacifier users rarely sucked their digits. There were temporal differences throughout the night in the distribution of different types of sucking and in infant state during and around sucking episodes. Sleeping in the 'non-routine' location was associated with a larger percentage of nights with sucking episodes and increased sleep latency. Bed sharing (routinely or on a given night) was associated with less sucking behavior and more breastfeeding. Non-nutritive sucking was not, however, associated with decreased total time breastfeeding per night or number of feeds per night.

CONCLUSION

Patterns of NNS during the night change with age and are affected by maternal proximity. Digit sucking has state modulating effects, and may be suppressed by pacifier use. Thus any benefits of pacifier use must be set against the potential loss of a self-directed ability to modulate state during the night, and possible shortening of breastfeeding duration.

Infant care practices in a metropolitan aboriginal population Bibbulung Gnarneep Team

OBJECTIVE

To describe sleeping position, room and bed-sharing, tobacco smoke exposure and infant feeding for a sample of Australian Aboriginal infants from a metropolitan area.

METHODS

Interviews with Aboriginal mothers who resided in the Perth metropolitan area and had given birth during a continuous 15-month study period. The interviews took place when the infants were approximately 6-12 weeks old and efforts were made to contact all eligible mothers. Results are presented as proportions with 95% confidence intervals.

RESULTS

Of all the eligible mothers (n = 515), 87% were contacted and 53% (n = 273) completed the interview. Of all the infants, 11% slept prone, 96% shared a room and 68% shared a bed; 65% of mothers smoked during pregnancy and 65% were smokers at the time of interview; 66% of the partners were smokers and 80% of the infants were regularly exposed to tobacco smoke; 89% of mothers initiated breast-feeding and 70% were breast-feeding at time of interview.

CONCLUSION

Prevalences of non-prone sleeping and breast-feeding are similar to the overall Western Australian population, whilst tobacco smoke exposure of the infants is markedly higher. Programs of community and family education and support are required urgently to decrease this exposure.

Infant sleep position. Nursing practice and knowledge

PURPOSE

(1) to examine the extent to which maternal/child health nurses caring for children accept the American Academy of Pediatrics recommendations on infant sleep position, (2) to determine if nurses are practicing according to the AAP recommendations, and (3) to determine the type of bedding utilized in the two institutions for infants.

METHODS

Descriptive survey using 103 nurses in 2 institutions, and an observational assessment of nurses' practice.

RESULTS

Findings revealed that 97% of the nursing staff were aware of the AAP recommendations, although only 67% agreed with the recommendations. The observational component of the investigation evaluated the sleep position during hospitalization of 206 infants < 6 months old on both the pediatric and maternity units of the two institutions. Fifty-five percent of the infants were observed to be in the side-lying position, 29% in the recommended supine (back) position, and 16% in the prone (abdomen) sleeping position. The recommended firm bedding was observed with 63% of the infants, whereas the remainder of the infants were observed to be on foam mattresses, extra blankets, or gel packs.

CLINICAL IMPLICATIONS

Because side sleeping position was observed in the majority of infants, and one-third of the nurses queried disagreed with the AAP recommendations, education of nurses about Sudden Infant Death Syndrome prevention through "Back to Sleep" is still necessary.

Breastfeeding patterns in relation to thumb sucking and pacifier use

OBJECTIVES

To analyze the influence of thumb sucking and pacifier use on breastfeeding patterns in exclusively breastfed infants, on the duration of exclusive breastfeeding, and on the total breastfeeding duration.

STUDY DESIGN

Descriptive, longitudinal, prospective study.

SETTING

The subjects were recruited from a population of 15 189 infants born in the maternity ward at the University Hospital, Uppsala, Sweden between May 1989 and December 1992.

STUDY POPULATION

506 mother-infant pairs.

METHODS

Daily recordings by the mothers on infant feeding from the first week after delivery through the duration of the study. Fortnightly home visits with structured interviews by a research assistant.

RESULTS

Pacifier use was associated with fewer feeds and shorter suckling duration per 24 hours, shorter duration of exclusive breastfeeding, and shorter total breastfeeding duration compared with no pacifier use. These associations were not found for thumb sucking. The possible negative effects of pacifiers on breastfeeding seemed to be related to the frequency of their use. Maternal age and education only slightly modified the association between pacifier use and breastfeeding duration.

CONCLUSIONS

More frequent use of a pacifier was associated with shorter breastfeeding duration, even among a group of mothers who were highly motivated to breastfeed. breastfeeding duration, breastfeeding pattern, exclusive breastfeeding, pacifier use, thumb sucking.

Epidemiology of SIDS and explained sudden infant deaths. CESDI SUDI Research Group

OBJECTIVES

To establish whether epidemiologic characteristics for sudden infant death syndrome (SIDS) have changed since the decrease in death rate after the "Back to Sleep" campaign in 1991, and to compare these characteristics with sudden and unexpected deaths in infancy (SUDI) from explained causes.

DESIGN

Three-year, population-based, case-control study. Parental interviews were conducted soon after the death and for 4 controls matched for age and date of interview. All sudden unexpected deaths were included in the study and the cause of death was established by a multidisciplinary panel of the relevant health care professionals taking into account past medical and social history of the mother and infant, the circumstances of death, and a full pediatric postmortem examination. Contributory factors and the final classification of death were made using the Avon clinicopathologic system.

SETTING

Five regions in England, with a total population of >17 million people, took part in the study. The number of live births within these regions during the particular time each region was involved in the study was 473 000.

STUDY PARTICIPANTS

Three hundred twenty-five SIDS infants (91.3% of those available), 72 explained SUDI infants (86.7% of those available), and 1588 matched control infants (100% of total for cases included).

RESULTS

Many of the epidemiologic features that characterize SIDS infants and families have remained the same, despite the recent decrease in SIDS incidence in the United Kingdom. These include the same characteristic age distribution, few deaths in the first few weeks of life or after 6 months, with a peak between 4 and 16 weeks, a higher incidence in males, lower birth weight, shorter gestation, and more neonatal problems at delivery. As in previous studies there was a strong correlation with young maternal age and higher parity and the risk increased for infants of single mothers and for multiple births. A small but significant proportion of index mothers had also experienced a previous stillbirth or infant death. The majority of the SIDS deaths (83%) occurred during the night sleep and there was no particular day of the week on which a significantly higher proportion of deaths occurred. Major epidemiologic features to change since the decrease in SIDS rate include a reduction in the previous high winter peaks of death and a shift of SIDS families to the more deprived social grouping. Just more than one quarter of the SIDS deaths (27%) occurred in the 3 winter months (December through February) in the 3 years of this study. In half of the SIDS families (49%), the lone parent or both parents were unemployed compared with less than a fifth of control families (18%). This difference was not explained by an excess of single mothers in the index group. Many of the significant factors relating to the SIDS infants and families that distinguish them from the normal population did not distinguish between SIDS and explained SUDI. In the univariate analysis many of the epidemiologic characteristics significant among the SIDS group were also identified and in the same direction among the infants dying as SUDI attributable to known causes. The explained deaths were similarly characterized by the same infant, maternal, and social factors, 48% of these families received no waged income. Using logistic regression to make a direct comparison between the two index groups there were only three significant differences between the two groups of deaths: 1) a different age distribution, the age distribution of the explained deaths peaked in the first 2 months and was more uniform thereafter; 2) more congenital anomalies were noted at birth (odds ratio [OR] = 3.14; 95% confidence intervals [CI]: 1.52-6. (ABSTRACT TRUNCATED)

Laryngeal basement membrane thickening is not a reliable postmortem marker for SIDS: results from the Chicago Infant Mortality Study

It has been suggested that laryngeal basement membrane (LBM) thickening is a pathognomonic postmortem marker for sudden infant death syndrome (SIDS) and is not seen in other causes of explained sudden infant death. To test this hypothesis, we evaluated longitudinal sections of the right hemilarynx taken through the midpoint of the true vocal cord from 129 SIDS cases and 77 postneonatal sudden infant death controls. Using a five-point semi-quantitative scale, maximum LBM thickness (LBMT) for SIDS cases and controls was not statistically different (mean, 2.39 + 0.69 and 2.40 + 0.77, respectively). Likewise, scores based on the average thickness along the entire basement membrane (i.e., "average" score), were not found to be different between SIDS cases and controls. Average and maximum LBMT increased with age in both SIDS cases and controls and were not different between SIDS cases and controls within each age interval. Similar trends in the distribution of maximum and average LBMTs were found between black and Hispanic SIDS and controls; the number of white/non-Hispanic infants was too low for meaningful comparisons. Maximum and average LBMTs were not different in SIDS cases and controls exposed to environmental tobacco compared with unexposed infants. The LBMTs also increased significantly with body weight and length in both SIDS cases and controls. Finally, there were no differences in LBMT in infants intubated prior to death compared with those who were not intubated. From these data, we conclude that LBMT is not pathognomonic of SIDS, is present or absent with equal frequency in SIDS and controls, increases with postnatal age, and does not correlate with passive smoke exposure. Therefore, LBMT should not be used to diagnose SIDS.

Inflammatory responses in sudden infant death syndrome -- past and present views

Sudden infant death syndrome (SIDS) is sudden unexpected death in infancy for which there is no explanation based on commonly accepted diagnostic criteria; however, half of the victims have had slight signs of infection prior to death. Such slight infection with fever is an important risk factor in combination with a prone sleeping position, especially in infants between 2 and 4 months of age. The purpose of this review is to summarise findings that support the theory that a significant part of cot deaths may be due to an overreaction to otherwise harmless infections. Such factors are mucosal immune stimulation, cytokines in the cerebrospinal fluid and hypoxanthine levels in vitreous humour. The review aims at explaining why we believe that a slight infection combined with a prone position, a warm environment and a vulnerable age period may trigger a vicious circle leading to death.

Use of duvets and the risk of sudden infant death syndrome

BACKGROUND

The use of duvets in infancy is not recommended in the UK and Australia because of a reported association with sudden infant death syndrome (SIDS).

AIMS

To examine the association between the use of duvets and the risk of SIDS.

METHODS

A nationwide case control study (393 cases, 1592 controls). The use of duvets was assessed by interview with the parent or guardian.

RESULTS

The use of duvets was associated with an increased risk of SIDS (odds ratio (OR) = 1.65; 95% confidence interval (CI), 1.31 to 2.08); however, after adjustment for potential confounders there was no increased risk of SIDS (OR = 1.04; 95% CI, 0.77 to 1.38). Furthermore, subgroup analysis did not identify any group in which the use of duvets was associated with an increased risk of SIDS.

CONCLUSIONS

This study does not support the recommendation to avoid duvets.

Case control study of thermal environment preceding haemorrhagic shock encephalopathy syndrome

The purpose of the study was to investigate whether the thermal environment in which babies slept before developing haemorrhagic shock encephalopathy syndrome (HSES) differed from that of other babies. Data were collected by standardised interview from parents of 31 babies who had had HSES before the age of 7 months and compared with equivalent data for 124 control babies, with matching for outside temperature on the relevant night and for age. Multivariate analysis showed a strong association between HSES and covering of the baby's head by bedding, the odds ratio being 30.7 (95% confidence interval, 2.5 to 384). There were weaker associations with other aspects of the thermal environment. This suggests a link between HSES and some cases of cot death, supports the suggestion that HSES may be caused by overheating, and reinforces advice that babies should be placed to sleep in such a way that they are less likely to become totally covered.

Pacifier use and sudden infant death syndrome: results from the CESDI/SUDI case control study. CESDI SUDI Research Team

OBJECTIVES

To investigate the relation between pacifier use and sudden infant death syndrome (SIDS).

DESIGN

Three year population based, case control study with parental interviews for each death and four age matched controls.

SETTING

Five regions in England (population > 17 million).

SUBJECTS

325 infants who had died from SIDS and 1300 control infants.

RESULTS

Significantly fewer SIDS infants (40%) than controls (51%) used a pacifier for the last/reference sleep (univariate odds ratio (OR), 0.62; 95% confidence interval (CI), 0.46 to 0.83) and the difference increased when controlled for other factors (multivariate OR, 0.41; 95% CI, 0. 22 to 0.77). However, the proportion of infants who had ever used a pacifier for day (66% SIDS v 66% controls) or night sleeps (61% SIDS v 61% controls) was identical. The association of a risk for SIDS infants who routinely used a pacifier but did not do so for the last sleep became non-significant when controlled for socioeconomic status (bivariate OR, 1.39 (0.93 to 2.07)).

CONCLUSIONS

Further epidemiological evidence and physiological studies are needed before pacifier use can be recommended as a measure to reduce the risk of SIDS.

Short-term morbidity and infant mortality among infants who slept supine at 1 month of age--a follow-up report

Following evidence that prone sleeping is causally related to sudden infant death syndrome (SIDS), intervention campaigns to avoid prone sleeping in many countries have led to a large reduction in SIDS and total infant mortality. The supine position has been recommended for healthy infants in several countries. The objective of this report was to determine how usual sleep position at 1 month relates to morbidity indicators at 1 month and 12 weeks and to SIDS and postneonatal mortality using a prospective population-based live birth cohort in Tasmania, Australia. Eligible infants were the one-fifth of Tasmanian live births at higher risk of SIDS using a perinatal score. From 1 January 1988 to 31 December 1995, 9826 (89% of eligible) infants participated in the home interview. Fifty-three eligible infants died of SIDS, 51 (96%) with hospital interview data and 35 (81% of those eligible for home visit) with home visit data. The main outcome measures were SIDS, postneonatal mortality and parentally reported infant morbidity. The postneonatal mortality rates (cases per 1000 live births) by usual sleep position at 1 month of age were supine 1.60 [95% CI 0.04, 8.87], side 2.87 [1.79, 4.35], prone 10.27 [5.62, 17.18] and other (including no usual position) 6.37 [0.16, 34.98]. None of the study infants who slept supine died of SIDS at a later time. Of 25 morbidity indicators studied, only noisy breathing was increased for supine compared with side-sleeping babies. In this study, there was no evidence to suggest that supine sleeping at 1 month of age was associated with an increase in important short-term morbidity or postneonatal mortality. These findings provide further support for the recent recommendations of the American Academy of Pediatrics that healthy infants should preferably sleep in the supine position.

International child care practices study: methods and study population

The study set out to document child care practices in as many different countries and cultures as possible with the aim of providing baseline child care data and stimulating new hypotheses to explain persisting differences in sudden infant death syndrome (SIDS) rates between countries. The protocol, piloted in four countries in 1992, was distributed to 80 potential centres in 1995. Data from 19 centres were received. This paper describes the demographic characteristics of the data from the different centres. Comparison showed significant differences for a number of variables including mean age of completion of the study, response rate, mean gestation, mean birth weight, method of delivery and incidence of admission to neonatal intensive care units. High caesarean section rates identified in the Chinese samples (44 and 40%) were unexpected and have important public health implications. This finding warrants further study but may be related to China's one child policy. We consider that international comparison of child care practice is possible using standardised data collection methods that also allow some individual variation according to local circumstances. However, in view of the heterogeneity of the samples, it will be important to avoid over-interpreting differences identified and to view any differences within the qualitative context of each individual sample. Provided there is acknowledgement of limitations, such ecological studies have potential to produce useful information especially for hypothesis generation.

Head turning and face-down positioning in prone-sleeping premature infants

BACKGROUND

Term infants may die of sudden infant death syndrome (SIDS) when they assume the face-straight-down or the face-near-straight-down head positions. Preterm infants have a higher SIDS rate, but it is not known how often they assume the face-straight-down and face-near-straight-down positions.

OBJECTIVES

To determine the frequency and cardiorespiratory consequences of head turning and face-down head positioning in prone-sleeping premature infants.

STUDY DESIGN

Supervised overnight cardiorespiratory and audiovisual recordings were conducted in 15 prone-sleeping preterm infants nearing hospital discharge: birth weight, 1178 101 (SEM) g, postconceptional age, 40 1.0 weeks.

RESULTS

The preterm infants, studied at a younger postconceptional age than previously reported term infants, seldom turned their heads during sleep; therefore they rarely assumed the face-straight-down position (6 episodes in 3 infants) or the face-near-straight-down position (30 episodes in 6 infants).

CONCLUSIONS

Prematurely born infants, known to be at increased risk of SIDS, rarely assume face-down positions when sleeping prone at approximately 40 weeks' postconceptional age. These results suggest that head turning during sleep is developmentally regulated and may have relevance to understanding the age distribution of SIDS.

Unnatural sudden infant death

AIM

To identify features to help paediatricians differentiate between natural and unnatural infant deaths.

METHOD

Clinical features of 81 children judged by criminal and family courts to have been killed by their parents were studied. Health and social service records, court documents, and records from meetings with parents, relatives, and social workers were studied.

RESULTS

Initially, 42 children had been certified as dying from sudden infant death syndrome (SIDS), and 29 were given another cause of natural death. In 24 families, more than one child died; 58 died before the age of 6 months and most died in the afternoon or evening. Seventy per cent had experienced unexplained illnesses; over half were admitted to hospital within the previous month, and 15 had been discharged within 24 hours of death. The mother, father, or both were responsible for death in 43, five, and two families, respectively. Most homes were disadvantaged--no regular income, receiving income support--and mothers smoked. Half the perpetrators had a history of somatising or factitious disorder. Death was usually by smothering and 43% of children had bruises, petechiae, or blood on the face.

CONCLUSIONS

Although certain features are indicative of unnatural infant death, some are also associated with SIDS. Despite the recent reduction in numbers of infants dying suddenly, inadequacies in the assessment of their deaths exist. Until a thorough postmortem examination is combined with evaluation of the history and circumstances of death by an experienced paediatrician, most cases of covert fatal abuse will go undetected. The term SIDS requires revision or abandonment.

Case-control study of current validity of previously described risk factors for SIDS in The Netherlands

This study aimed to assess whether previously established risk factors for sudden infant death syndrome (SIDS) are still valid now that the incidence in the Netherlands has dropped to 0.26 per 1000 liveborn infants. A distinction was made between immutable and mutable risk factors. This case-control study (part of the European Concerted Action on SIDS) comprised 73 SIDS cases and 146 controls and lasted from March 1995 to September 1996. Adjustments were made for sleeping position and bedding factors by treating them as covariables. Apart from these factors, well known risk factors that remain of importance in the Netherlands are: male sex, young maternal age, twins, and low socioeconomic status. These factors are largely immutable. Other well known risk factors which might reflect attitudes to child care and could possibly be mutable are: smoking, alcohol consumption by the mother, bottle feeding, and change of babycare routine. Intervention strategies should focus on early signalling, thereby assisting parents in changing these unfavourable parenting attitudes. Information on optimal child care and extra support by public health nurses specifically aimed at families at risk could help to decrease further the incidence of SIDS in the Netherlands.