Growth and the sudden infant death syndrome

Objective : To compare the growth curves based on measurements of body weight for male and female infants dying of sudden infant death syndrome (SIDS) with those of male and female controls. Methods : The data were drawn from a large case control study of SIDS carried out in New Zealand between 1987 and 1990. Results : The mean birthweight for the cases was 3049 g and for the controls 3526 g. The mean growth curves for the male and female controls were close to the 50th centile of growth charts used in New Zealand. The growth curve for the male cases diverged from that of the controls, being closer to the 25th percentile. The differences between the female cases and controls were less pronounced. The differences in weekly weight increments derived from the curves for the cases and controls for nine 4-week periods were not statistically significant after taking into account race, manner of feeding and maternal smoking for any 4-week period. Conclusions : SIDS cases were lighter at birth, but their growth velocity was normal postnatally.     

Metal content of the liver in sudden infant death syndrome

Abstract The metals zinc, iron, copper, manganese, calcium, magnesium, potassium and sodium were analysed in the livers of 67 Australian infants who had died from Sudden Infant Death Syndrome (SIDS) and 29 infants who had died from other causes (non-SIDS). The results were evaluated in relation to medical data and fatty acid composition of the livers. In infants less than 6 months old the liver potassium levels were significantly lower in SIDS than in non-SIDS infants. No other significant differences in metals between the SIDS and non-SIDS livers were found. Zinc, iron and copper levels in infant liver fell with age during the first year.     

Gender and the sudden infant death syndrome

Abstract A nationwide case-control study compared the prevalence and magnitude of risk factors for sudden infant death syndrome (SIDS) in male and female infants. The risk factors of SIDS and their magnitude for males and females are very similar. After adjustment for potential confounders male infants had a 1.42-fold (95% CI = 1.04, 1.94) increased risk of SIDS compared with females. Risk factors identified in most epidemiological studies are not the reason for the increased SIDS mortality seen in male infants.     

Epidemiology of sudden infant death syndrome in Japan

An epidemiological survey was carried out to examine the present situation with respect to sudden infant death syndrome (SIDS) in Kanagawa Prefecture. Questionnaires on sudden unexpected death of infants aged < 1 year in 1990-91 were sent to the hospitals and clinics in Kanagawa Prefecture which may take care of such infants. By analysing information from 10 485 replies, 48 out of 73 reported sudden infant deaths were confirmed to be SIDS, although autopsy was not performed in 13 cases (27%). The incidence of SIDS per 1000 live births in Kanagawa Prefecture was 0.29 in 1990 and 0.31 in 1991; and if limited to autopsy cases 0.19 and 0.25, respectively. Sudden infant death syndrome cases in Japan were found to occur more frequently when infants were < 6 months old, at home and sleeping alone, but less in the winter and between midnight and early morning. There was little difference between the numbers in prone and supine sleeping positions at discovery. It was not clear whether SIDS occurred more often to babies sleeping prone than supine, because there were no controls matched with the SIDS cases. In future, continuous epidemiological surveys of SIDS in Japan should be carried out.     

Sudden infant death syndrome and infant mortality in Aboriginal and non-Aboriginal infants

The aim of this study was to investigate sudden infant death syndrome (SIDS) in the context of total infant mortality for Aboriginal and non-Aboriginal infants. Deaths for infants born in Western Australia from 1980 to 1988 inclusive were ascertained from a total population data base. Infant mortality rates and rates by period and cause of death were calculated for both populations. Aboriginal infants had a mortality rate three times that for non-Aboriginal infants (23.6 cf. 7.9 per 1000 live births) and both populations showed a similar rate of decline in mortality over the study period. There were differences in the proportion of deaths occurring neonatally and postneonatally in the two populations. In terms of SIDS, 21% of the deaths in Aboriginal infants occurred neonatally compared with 7% for non-Aboriginal infants. The overall cause of infant death distribution differed significantly between the two populations ( P < 0.001). During the study period, Aboriginal infants showed a significant increase in deaths due to SIDS and a significant decrease in those due to birth defects and low birthweight. These results suggest it would be useful to review the pathology and diagnosis of sudden unexplained death in infancy.     

Overview of sudden infant death syndrome in Japan

In spite of rapid medical advancement in the care of infants and children, not only the general public but also many medical personnel have remained unaware of sudden infant death syndrome (SIDS) until very recently in Japan. In 1981, a research project team on SIDS financed by the Ministry of Health and Welfare was founded. Current incidence of SIDS is estimated to be about 0.5 per 1000 live births. The SIDS Family Association was organized in 1993 in Japan and began to publicize the social importance of SIDS and to support SIDS families by training befrienders. A series of articles on current achievements from SIDS research projects and from the SIDS Family Association are submitted to this issue. The present paper summarizes the status of SIDS in Japan by overviewing the activities of the research team and the SIDS Family Association.     

Near miss sudden death in an infant with Wolff-Parkinson-White syndrome

A 6 month old infant with known Wolff-Parkinson-White syndrome presented with an out of hospital cardiac arrest. An electrocardiogram in the emergency department demonstrated atrial fibrillation with rapid ventricular response. The child subsequently was resuscitated and underwent successful interruption of an accessory connection after failing medical therapy. This case underlines the need to reassess the indications for invasive electrophysiologic testing in young children.     

Well health care and the sudden infant death syndrome

The aim of this study was to examine whether poor attendance at routine antenatal and postnatal 'well child' health services was associated with a higher risk of sudden infant death syndrome (SIDS, or cot death). A nationwide case-control study of SIDS in New Zealand enrolled 485 postneonatal deaths due to SIDS and 1800 control infants who were selected randomly. The risk for SIDS was found to be higher for infants whose mothers attended their first antenatal check later than 3 months into the pregnancy, made fewer antenatal visits, and did not go to antenatal education classes. However, this increased risk was largely explained by high parity, maternal smoking, the mother not being married, mother being <20 years old at the birth of her first child, and delivery during the winter months. Infants not attending a 6 week postnatal check had an almost three-fold increased risk of SIDS compared with those who did attend (odds ratio [OR] 2.86; 95% confidence interval [Cl] 1.93, 4.24). Similarly, infants not attending well child clinics were at increased risk of SIDS (OR 2.75; 95% Cl 2.09, 3.62). These differences persisted when adjusted for likely confounders. This study demonstrates that infants who miss child health nurse clinics are those most at risk for SIDS and are those who warrant increased surveillance.     

Seasonality of sudden infant death syndrome (SIDS) by age at death

Seasonality of sudden infant death syndrome (SIDS) is a well-established epidemiological finding. The purpose of the study was to determine whether this feature varied significantly with age at death. In total, 13 990 cases of SIDS in Scotland, England and Wales during 1982–1992 were studied by age group at death. Seasonality was established by fitting a sinusoidal curve and for each set of monthly data the peak position in the year and its magnitude were determined. Weighted regression revealed significant differences in peak position and amplitude of seasonal variation between those dying at ≤ 4 months and those aged ≥ 5 months at death. Those infants in the younger age group were more likely to die earlier in the winter months and had a smaller variation in seasonality. The peak (acrophase) months were January for ≤ 4 months and February for ≥ 5 months at death. Weighted regressions of peak position and amplitude on age at death had p-values of < 0.001 and < 0.01, respectively. A log linear model relating SIDS incidence to month of birth, month of death and age was able to explain some of these findings. The findings support the hypothesis that in SIDS there may be more than one infant cohort, each of which passes through a vulnerable developmental window at different ages.     

Issues in diagnosis following the sudden infant death syndrome intervention campaigns

Abstract: The fall in numbers of sudden infant death syndrome (SIDS) deaths in recent years has resulted in questions being asked as to whether changes in the pathological assessment and diagnosis of such cases have influenced reported death rates. Specific concerns have been raised about possible changes in diagnostic criteria, differences in the evaluation of these infants and the possibility of changes in the pathological findings at autopsy. However, no major changes in either diagnostic criteria or in pathological features appear to have occurred, despite some changes in the epidemiological characteristics of cases.     

Developmental brain-stem pathology in sudden infant death syndrome

The brain-stems of control and sudden infant death syndrome (SIDS) infants were examined developmentally with Golgi and immunohistochemical methods. The development of dendritic spines changed dramatically from the prenatal to postnatal period in the ventrolateral medulla as well as in the reticular formation and vagal nuclei in controls, but persisted in SIDS infants. These observations suggest a delay in maturation of the meduallary respiratory neurons and transneuronal connection between the central chemoreceptor and neural respiratory center in SIDS. In addition, substance P (SP)-positive nerve fibers were increased in the pons of SIDS infants. An increased activity in the afferent SP neurons in SIDS may be due to chronic hypoxia as in brain-stem gliosis, and may be involved in cardiorespiratory regulation.     

Home monitoring for infants at risk of the sudden infant death syndrome

Abstract This study evaluates the effectiveness and social implications of home monitoring of 31 infants at risk of sudden infant death syndrome (SIDS). Thirteen siblings of children dying of SIDS, nine near miss SIDS infants and nine preterm infants with apnoea persisting beyond 40 weeks post conceptual age were monitored from a mean age of 15 days to a mean of 10 months. Chest movement detection monitors were used in 27 and thoracic impedance monitors in four. Genuine apnoeic episodes were reported by 21 families, and 13 infants required resuscitation. Apnoeic episodes occurred in all nine preterm infants but in only five (38%) of the siblings of SIDS (P<0.05). Troublesome false alarms were a major problem occurring with 61% of the infants and were more common with the preterm infants than the siblings of SIDS. All but two couples stated that the monitor decreased anxiety and improved their quality of life. Most parents accepted that the social restrictions imposed by the monitor were part of the caring process but four couples were highly resentful of the changes imposed on their lifestyle.
The monitors used were far from ideal with malfunction occurring in 17, necessitating replacement in six, repair in six and cessation of monitoring in three. The parents became ingenious in modifying the monitors to their own individual requirements
Although none of these 31 'at risk' infants died the study sample was far too small to conclude whether home monitoring prevented any cases of SIDS.     

Autopsies of sudden infant death syndrome—classification and epidemiology

An enquiry into sudden infant death syndrome (SIDS) in 1987 furnished us with detailed epidemiological data for 281 cases that underwent a thorough post-mortem examination. This analysis uses these data to evaluate the role the autopsy plays in explaining sudden death. The cases were classified into three diagnostic groups: explained causes of death (group 1), unexplained deaths with anomalies (group 2), and no anomaly (group 3). These 281 cases show the three essential features that characterize SIDS: over-representation of males, increased deaths during the second and third months of life, and increased deaths during winter. The autopsy examination revealed that many of these deaths had a medical explanation. Almost half were assigned to group 1. At the time of autopsy, no precise pathology could be diagnosed for 147 deaths; of these, 140 showed histological anomalies. There were only seven sudden deaths for which no abnormal sign was evident at the autopsy. These results are compared with those of similar studies and discussed in connection with three factors: the initial selection of cases, the nature and degree of the investigations, and the possible interpretations of the symptoms uncovered.     

Routine microbiological testing in sudden and unexpected infant death

Objective : To evaluate the significance of microbiological test results in a series of infants who had died suddenly and unexpectedly.
Methodology : Following a review of all cases of sudden natural death in infants presenting to the Adelaide Children's Hospital (ACH) division of the Women's and Children's Hospital (WCH) over the 10 year period between 1983 and 1992, specific evaluation of microbiological test results was undertaken.
Results : There were 329 cases of sudden infant death syndrome (SIDS) and 23 cases in which sudden infant death was either attributed to other conditions or was unclassifiable. Positive microbiological results were recorded in the majority of cases, most being considered to be due to postmortem overgrowth or to contamination at autopsy. Of the remaining cases, microbiological results were essential to the establishment of the diagnosis in three cases, and were a useful adjunct to the diagnosis in a further six cases.
Conclusions : Routine microbiological testing in cases presenting as SIDS did not reveal occult sepsis in most instances. Such testing did, however, add support to the diagnosis of SIDS where no pathogens were isolated and, if not undertaken, would have resulted in a small percentage of cases of sudden infant death due to infections remaining undiagnosed.     

Child care practices and the sudden infant death syndrome

Abstract Southern New Zealand has one of the highest reported rates of the sudden infant death syndrome (SIDS) in the world. Data were collected on 49 infants who died from SIDS in the Dunedin and Invercargill Health Districts of southern New Zealand. Forty-two of the families were interviewed at home following the loss of their infant. In the week prior to death, 17 infants (40%) had an upper respiratory tract infection, although in 11 of these infants their infection had apparently resolved at least 24 h prior to death. Thirty infants (71%) had their faces down into the bedding or their heads covered with bedding. Thirty-four infants (81%) were found dead in the prone position, whereas 49% of New Zealand infants aged 3 months would be expected to sleep prone. Sleep position and the terminal position of the head in relation to SIDS requires further study.     

Couple distress after sudden infant or perinatal death: a 30-month follow up

OBJECTIVE: To examine, using a 30-month prospective study, patterns of anxiety, depression and alcohol use in couples following stillbirth, neonatal death or sudden infant death syndrome. METHODOLOGY: One hundred and thirty-eight bereaved and 156 non-bereaved couples completed standardized interviews at 2, 8, 15 and 30 months post-loss. RESULTS: At all interviews, bereaved couples were significantly more likely than non-bereaved couples to have at least one distressed partner. Rarely were both partners distressed in either group. For bereaved couples, 'mother only' distress declined from 21% to 10% during the study. 'Father only' distress ranged from 7% to 15%, peaking at 30 months. Bereaved mothers who were distressed at 2 months reported significantly lower marital satisfaction at 30 months. CONCLUSIONS: At the couple level, the experience of a baby's death is multifaceted. Gender differences are common and partners' needs may change over time. Early recognition of these differences may facilitate longer-term adjustment for both partners.     

Dummy (pacifier) use and sudden infant death syndrome: Potential advantages and disadvantages

The large decline in deaths due to the sudden infant death syndrome (SIDS) in the last 20 years in many countries is largely due to risk‐reduction advice resulting from observational studies that examined the relationship between infant care practices and SIDS. Most of this advice remains largely uncontroversial and educators and researchers in this field are in agreement as to the specific recommendations that should be given to parents and health professionals. However, advice surrounding the apparent protective effect of dummies (also known as pacifiers) has been controversial. Several systematic reviews have demonstrated a strong association between the lack of a pacifier being used by the infant for the final sleep and SIDS, but it is not clear how pacifiers confer protection or if this is a marker for something as yet unmeasured. The Epidemiology and Physiology Working Groups of the International Society for the Study and Prevention of Perinatal and Infant Death (ISPID) are comprised of leading SIDS researchers with an objective to provide evidence‐based position statements surrounding the factors associated with SIDS ( http://www.ispid.org/ ) and risk‐reduction strategies. The evidence, discussion and conclusions from these working groups regarding dummies (pacifiers) are described below to help inform this debate and describe the future evidence required so that we might find a common recommendation about dummies (pacifiers) and SIDS.     

Clostridium botulinum and sudden infant death syndrome: A 10 year prospective study

It has been proposed that sudden and unexpected death in infants due to intestinal infection with Clostridium botulinum may mimic the clinicopathological features of sudden infant death syndrome. Between 3.3 and 3.8% of infants in some series have had this neurotoxin-producing bacterium isolated on faecal culture. Prospective screening of 248 infants presenting with the sudden infant death syndrome to the Adelaide Children's Hospital over a 10 year period from 1981 to 1990 was conducted. Faecal samples were obtained from both small and large intestines and cultured specifically for C. botulinum. No samples were positive. The results of this study suggest that routine post-mortem culture of faeces for C. botulinum has been of limited use within the South Australian infant population over the last decade, and that occult botulism has not been a significant factor in the causation of sudden death.     

Early neonatal sudden death or near death syndrome. An epidemiological study of 29 cases

Early neonatal sudden death syndrome (SIDS) is a rare but well known disease entity. Between January 1975 and December 1991, 29 full-term newborn infants delivered in our maternity unit and, considered healthy at birth, suffered early SIDS ( n = 15) or early apparent life threatening events (ALTE) ( n = 14). Data from the whole population of live full-term infants born in our hospital during the past five years have been used as a reference (n = 27 841). The general rate of early SIDS was 0.14 per 1000 (15/107 263). Combining early ALTE cases, the overall rate was 0.27 per 1000 (291107263). A postmortem examination was performed for all infants who died (20/29): no cause of death could be determined, and we did not observe a single case with evident sequelae. There were 9 deaths (31 %) within the first hour after delivery and 12 deaths occurred in the early morning hours (04:00–08:00; RR = 3.76; p = 0.0008). The lowest incidence was in the spring (RR = 0.21; p = 0.03). There was a tendency for an increased incidence during the weekend and the summer. No influence of sex, maternal age, gestational age, infant weight presentation, delivery, anesthesia or presence of meconium-stained fluid was found. In our opinion, SIDS can take place even during the first hour of life and it is not possible to predict when a baby might be affected. Pediatrically trained caregivers, close observation by the mother during the first few days and resuscitation facilities in maternity wards may be the most important preventive measures to reduce the risk of early SIDS and the consequences of ALTE in the early newborn period.