In Germany, 2910 infants died in 2004; for many infants the reason was clear, especially prematurity or congenital abnormalities. However, 394 babies die every year suddenly and unexpectedly. The cause may be immediately clear, but is often not obvious.
(1) To describe the causes of explained sudden unexpected death in infancy (SUDI) and (2) to compare risk factors for sudden infant death syndrome (SIDS) and explained SUDI.
A 3‐year population‐based case–control study in Germany, 1998–2001.
455 deaths, of which 51 (11.2%) were explained. Most of these deaths were due to respiratory or generalised infections. The risk factors for SIDS and explained SUDI were remarkably similar except for sleep position and breast feeding. Prone sleeping position is a major risk factor for SIDS (adjusted odds ratio (OR) 7.16, 95% confidence interval (CI) 3.85 to 13.31) but not for explained SUDI (adjusted OR 1.71, 95% CI 0.25 to 11.57). Not being breast fed in the first 2 weeks of life is a risk factor for SIDS (adjusted OR 2.37, 95% CI 1.46 to 3.84) but not for explained SUDI (adjusted OR 0.39, 95% CI 0.08 to 1.83).
Prone sleeping position is a unique risk factor for SIDS. Socioeconomic disadvantage and maternal smoking are risk factors for both SIDS and explained SUDI, and provide an opportunity for targeted intervention.
the clinical characteristics associated with sudden infant death
syndrome (SIDS) and explained sudden unexpected deaths in infancy (SUDI).
population based, case control study with parental interviews for each
death and four age matched controls.
in England (population, > 17 million; live births, > 470 000).
SUBJECTS—SIDS: 325 infants; explained SUDI: 72 infants; controls: 1588infants.
univariate analysis, all the clinical features and health markers at
birth, after discharge from hospital, during life, and shortly before
death, significant among the infants with SIDS were in the same
direction among the infants who died of explained SUDI. In the
multivariate analysis, at least one apparent life threatening event had
been experienced by more of the infants who died than in controls
(SIDS: 12% v 3% controls; odds ratio (OR) = 2.55; 95% confidence interval (CI), 1.02 to 6.41; explained SUDI: 15% v 4% controls; OR = 16.81;
95% CI, 2.52 to 112.30). Using a retrospective illness scoring system
based on "Baby Check", both index groups showed significant markers
of illness in the last 24 hours (SIDS: 22%
v 8% controls; OR = 4.17; 95% CI, 1.88to 9.24; explained SUDI: 49% v 8%
controls; OR = 31.20; 95% CI, 6.93 to 140.5).
clinical characteristics of SIDS and explained SUDI are similar. Baby
Check might help identify seriously ill babies at risk of sudden death,
particularly in high risk infants.
OBJECTIVE: To analyse and describe the prevalence of sudden infant death syndrome (SIDS) in the Canadian population in relation to the distribution of known risk factors for the syndrome. To explain the observed interprovincial variation in SIDS rates. DESIGN: Retrospective population-based case-control study. SETTING: All the provinces and territories of Canada except Quebec. SUBJECTS: The birth and infant death records of singleton births for 1986-88 were linked. The linkage was successful in matching 904 (86%) of the 1053 deaths attributed to SIDS to the birth file for the infant. For each SIDS case three control babies who survived infancy were chosen at random, matched by province of birth. MAIN OUTCOME MEASURES: Infant death classified as a "sudden infant death." Independent variables included infant's sex, birth weight and gestational age, being small for gestational age, mother's age, marital status and parity, and father's age. RESULTS: The risk of SIDS was greater for boys (odds ratio [OR] 1.47, 95% confidence limits [CLs] 1.26 and 1.70) than for girls and was greater for the infants of unmarried women (OR 3.48, 95% CLs 2.94 and 4.11) than for those of married women. The risk of SIDS was inversely related to birth weight (p < 0.001), duration of pregnancy (p < 0.001) and mother's age (up to age 35) (p < 0.001) and was directly related to parity (up to four) (p < 0.001). The available information on birth and death registrations enabled about 30% of deaths from SIDS to be predicted. CONCLUSIONS: Logistic regression equations based on the risk factors available in vital statistics data have low power to predict provincial differences in rates of SIDS. Consequently, there may be additional factors that may explain provincial variation. There is a need for a well-designed case-control study that examines more variables than are available through vital registration systems.
To determine whether biochemical parameters of cholinergic and oxidative stress function including red cell acetylcholinesterase (AChE), serum/plasma thyroglobulin, selenium, iron, ferritin, vitamins C, E, and A affect risk in apparent life-threatening event (ALTE), sudden infant death syndrome (SIDS), and sudden unexpected death in infancy (SUDI). To assess these biochemical parameters as a function of age; and for influence of pharmacology and epidemiology, including infant health, care, and feeding practices.
A multicentre, case–control study with blood samples from 34 ALTE and 67 non-ALTE (control) infants matched for age, and 30 SIDS/SUDI and four non-SIDS/non-SUDI (post-mortem control) infants.
Levels/activity of the biochemical parameters were not significantly different in ALTE vs. control infants, with the exception of higher vitamin C levels in the ALTE group (p = 0.009). In ALTE and control groups, AChE and thyroglobulin levels increased and decreased respectively from birth to attain normal adult levels from 6 months. Levels of iron and ferritin were higher in the first 6 month period for all infant groups studied, intersecting with vitamin C levels peaking around 4 months of age.
Lower AChE levels and higher combined levels of iron and vitamin C in the first 6 months of life may augment cholinergic and oxidative stress effect, particularly at the age when SIDS is most prevalent. This may contribute to risk of ALTE and SIDS/SUDI events during infancy.
Cholinergic; Oxidative stress; Sudden infant death syndrome
The classification of an unexpected infant death as the sudden infant death syndrome (SIDS) depends upon a complete autopsy and death scene investigation to exclude known causes of death. Here we report the death of a four-month-old infant in a tuberculosis endemic area that presented as a sudden unexpected death in infancy (SUDI) with no apparent explanation based on the death scene characteristics. The autopsy, however, revealed progressive primary pulmonary tuberculosis with intrathoracic adenopathy, compression of the tracheobronchial tree and miliary lesions in the liver. This case underscores the clinical difficulties in the diagnosis of infantile tuberculosis, as well as the possibility of sudden death as part of its protean manifestations. The pathology and clinical progression of tuberculosis in infants differs from older children and adults due to the immature immune response in infants. This case dramatically highlights the need for complete autopsies in all sudden and unexpected infant deaths, as well as the public health issues in a sentinel infant tuberculosis diagnosis.
Airway obstruction; Tuberculosis; Autopsy; Sudden Infant Death Syndrome (SIDS); Sudden Unexplained Death in Infancy (SUDI); South Africa
Background: Twins compared to singletons are at increased risk of sudden infant death syndrome (SIDS).
Aims: To compare the epidemiology of SIDS in twins and singletons and to test the hypothesis that monozygous (MZ) were at greater risk of SIDS than dizygous (DZ) twins.
Methods: Data from the Office for National Statistics on all registered live births and infant deaths with registered cause of death "sudden unexpected death in infancy" in England and Wales from 1993 to 1998 were obtained, together with the registered birth weight and, for twins, whether they were of like or unlike sex.
Results: The crude relative risk of SIDS in twins is twice that in singletons. There has been a significant temporal decline in SIDS mortality. There is also a significant increase in risk with decreasing birth weight for both twins and singletons. The birth weight specific risk of SIDS in all except for those ≥3000 g is greater in singletons than in twins. There is no significant difference in risk of SIDS in like compared with unlike sex twins.
Conclusions: In spite of a lower risk of SIDS in twins compared with singletons for each birth weight group <3000 g, one component of the higher crude relative risk of SIDS in twins is attributable to the higher proportion of twins that are of low birth weight. A second component is the higher risk in twins compared with singletons for those of birth weight ≥3000 g. Like sex are at no greater risk than unlike sex twins, which suggests that zygosity is not a significant factor in SIDS.
In Lorain County, Ohio, unexplained infant deaths in homes sprayed with methyl parathion (MP), an organophosphate (OP) pesticide, prompted an investigation to determine whether infants living in treated homes are at higher risk for unexplained death. A case was defined as any death of an infant (12 months of age) in Lorain County between 1 January 1990 and 31 December 1994, attributed to sudden infant death syndrome (SIDS) or other unknown natural causes. For each case infant, birth certificate data were used to identify two control infants matched with regard to date of birth, sex, city of residence, and maternal race and educational level. Wipe samples from the home address listed on the birth certificate of control infants or the death certificate of case infants were analyzed for MP. Birth certificates provided additional risk factor information. The relationship between MP contamination and unexplained death was analyzed by exact conditional logistic regression. Wipe samples were collected from the residences of 34 case infants and 72 control infants. MP (>0.02 mg/100 cm2) was detected in five homes, three of which had been occupied by case infants. Case infants were 4.6 times more likely than control infants to have lived in MP-treated homes, but the confidence interval (CI) was wide (95% CI: 0.2, 274.7) and included 1. Maternal smoking, young maternal age, and the presence of other siblings in the family were each independently predictive of case status. In a multivariate model adjusting for these other variables and the matching variables, the estimated risk associated with MP exposure was 13.0 (95% CI: 0.2, 2,685.0). Although this association was not statistically significant and should be interpreted cautiously, it suggests an increased risk for unexplained death among infants living in MP-contaminated homes. The relationship between children's health and exposure to OP pesticides including MP should be evaluated further.
To describe underlying causes of infant death by birth weight, we used data from the 1980 National Infant Mortality Surveillance project and aggregated International Classification of Diseases codes into seven categories: perinatal conditions, infections, congenital anomalies, injuries, sudden infant death syndrome (SIDS), other known causes, and nonspecific or unknown causes. Compared with heavier infants, infants with birth weights of 500-2,499 grams (g) are at increased risk of both neonatal and postneonatal death for virtually all causes. Sixty-two percent of neonatal deaths (under 28 days of life) were attributed to "conditions arising in the perinatal period," as defined using codes from the International Classification of Diseases. Prematurity-low birth weight and respiratory distress syndrome (RDS) were the leading causes of such deaths among infants with birth weights of 500-2,499 g, while birth trauma-hypoxia-asphyxia and other perinatal respiratory conditions were the leading causes among heavier infants. For all birth weight groups, congenital anomalies were the second leading cause, representing 27 percent of neonatal deaths. Although perinatal conditions caused nearly one-third of postneonatal deaths (28 days to under 1 year of life) among infants with birth weights of 500-1,499 g, for the other birth weight groups these conditions were much less important; predominant causes of postneonatal death were sudden infant death syndrome (SIDS), congenital anomalies, infections, and injuries. Black infants had a roughly twofold higher risk of neonatal and postneonatal death than did white infants for all causes except congenital anomalies, which occurred with almost equal frequency in blacks and whites. However, for infants with birth weights of 500-2,499 g, blacks had lower risks of neonatal death from RDS and congenital anomalies. Between 1960 (the latest year for which national birth weight-specific mortality statistics had been available) and 1980, SIDS emerged as a major diagnostic rubric. Otherwise, except for infections and congenital anomalies among infants with birth weights of 500-1,499 g, all causes of death declined in frequency among all birth weight groups.
While the reduction in infants’ prone sleeping has led to a temporal decline in Sudden Infant Death Syndrome (SIDS), some aspects of this trend remain unexplained. We assessed whether changes in the gestational age distribution of births also contributed to the temporal reduction in SIDS.
SIDS patterns among singleton and twin births in the United States were analysed in 1995–96 and 2004–05. The temporal reduction in SIDS was partitioned using the Kitagawa decomposition method into reductions due to changes in the gestational age distribution and reductions due to changes in gestational age-specific SIDS rates. Both the traditional and the fetuses-at-risk models were used.
SIDS rates declined with increasing gestation under the traditional perinatal model. Rates were higher at early gestation among singletons compared with twins, while the reverse was true at later gestation. Under the fetuses-at-risk model, SIDS rates increased with increasing gestation and twins had higher rates of SIDS than singletons at all gestational ages. Between 1995–96 and 2004–05, SIDS declined from 8.3 to 5.6 per 10,000 live births among singletons and from 14.2 to 10.6 per 10,000 live births among twins. Decomposition using the traditional model showed that the SIDS reduction among singletons and twins was entirely due to changes in the gestational age-specific SIDS rate. The fetuses-at-risk model attributed 45% of the SIDS reduction to changes in the gestational age distribution and 55% of the reduction to changes in gestational age-specific SIDS rates among singletons; among twins these proportions were 64% and 36%, respectively.
Changes in the gestational age distribution may have contributed to the recent temporal reduction in SIDS.
SIDS; Temporal trend; Gestational age
Sudden infant death syndrome (SIDS) is defined as the sudden death of an infant under one year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene and review of the clinical history. SIDS is one of the leading causes of infant mortality and occurs from the first month, until the first year of life for newborns and infants.
The aim of this review was to identify and examine risk factors responsible for causing the sudden infant death and to propose certain measures in order to protect newborns and infants from sudden death. The potential factors that contribute to the occurrence of SIDS include inadequate prenatal care, low birth weight (<2499gr), premature infants, intrauterine growth delay, short interval between pregnancies and maternal substance use (tobacco, alcohol, opiates). Moreover, factors related to infant’s sleep environment such as the prone or side sleeping position and thick coverlet increase the risk of sudden death in infants. Also, the combination of risk factors such as that of prone sleeping position and soft bed mattress are linked to a 20-fold increased risk of death. Finally, polymorphisms in the serotonin transporter gene (5-HTT), viral respiratory infections, long Q-T (responsible for the presence of fatal arrhythmia) are related to the SIDS.
Literature review indicates that each individual risk factor contributes to the appearance of SIDS and the establishment of certain protective measures for parents and health professionals has reduced its prevalence. But the precise identification of the SIDS causes and how these contribute to the occurrence of sudden death in neonates and infants, remains a challenge for health professionals.
sudden death; newborn; infant; risk factors; prevention; review
STUDY OBJECTIVE--The aim was to investigate whether the winter increase in risk of sudden infant death was similar across social classes. DESIGN--This was an unmatched case-control study using routine data. SETTING--Cases and controls were selected from files holding routine birth and death certificate data for England and Wales for 1986. SUBJECTS--Cases were deaths in the first year of life occurring in the summer or the winter of 1986 with mention of sudden infant death or SIDS in the death certificate. Controls were a 1% random sample of all children born in the same year. Only children whose parents were married or living together at the time of birth registration were included. MAIN RESULTS--Data on age and season of death for cases, and on date of birth, social class of father, and birth weight were abstracted from the file. Season of birth and birth weight were treated as confounding variables. The increase in risk of SIDS in winter was calculated for each age group and social class. The winter increase in SIDS was more marked among the higher social classes for all ages, but not to a statistically significant degree: the p values for heterogeneity were 0.26 for age 0-3 months, 0.42 for 4-7 months, and 0.41 for 8-12 months. CONCLUSIONS--There is no direct association between seasonal variation in sudden infant death and social class.
In recent years, many babies who die of Sudden Unexpected Death in Infancy (SUDI) in Northern Ireland are found dead in bed – i.e. co-sleeping – with an adult. In order to assess its frequency autopsy reports between April 1996 and August 2001 were reviewed and linked to temporal factors. The day and month of death, and the place where the baby was found were compared to a reference population of infant deaths between one week of age and the second birthday.
Although the rate of SUDI was lower than the UK average, 43 cases of SUDI were identified, and two additional deaths with virtually identical autopsy findings that were attributed to asphyxia caused by suffocation due to overlaying. Thirty-two of the 45 (71%) were less than four months of age. In 30 of the 45 cases (67%) the history stated that the baby was bed sharing with others; 19 died sleeping in an adult bed, and 11 on a sofa or armchair. In 16 of the 30 (53%) there were at least two other people sharing the sleeping surface, and in one case, three. SUDI was twice as frequent at weekends (found dead Saturday – Monday mornings) compared to weekdays (p<0.02), and significantly more common compared to reference deaths (p<0.002). Co-sleeping deaths were also more frequent at weekends. Almost half of all SUDI (49%) occurred in the summer months – more than twice the frequency of reference deaths.
While sharing a place of sleep per se may not increase the risk of death, our findings may be linked to factors such as habitual smoking, consumption of alcohol or illicit drugs as reported in case-control studies. In advising parents on safer childcare practices, health professionals must be knowledgeable of current research and when, for example, giving advice on co-sleeping this needs to be person-specific cognisant of the risks within a household. New and better means of targeting such information needs to be researched if those with higher risk life-styles are to be positively influenced.
In 1985 twin boys simultaneously succumbed to sudden unexpected deaths two to three hours after vaccination with diphtheria, tetanus, and pertussis vaccine (DTP). This occurrence again raises the question of whether an association of sudden infant death (SID) with vaccination is other than temporal. Taking the incidence of SID in conjunction with rates of infant vaccination in the United Kingdom, nine infants would be expected to die, each year by chance alone, suddenly within 24 hours of (and within each 24 hour period succeeding) vaccination with DTP. Twins are at a greater risk of SID than single born infants and occasionally are found dead together. A number of studies into DTP vaccination as a risk factor in SID have shown that SID is less common in vaccinated than in unvaccinated infants.
The purpose of this study was to determine the relative importance of inadequate maternal weight gain as a cause of infant mortality.
Birth and infant death certificate data were obtained from a random sample of 100,000 records from the National Center for Health Statistics 2002 Linked Birth/Infant Death Data Set. Descriptive and proportional hazards regression analyses were used to assess the risk of infant mortality associated with inadequate gestational weight gain compared to normal weight gain.
Inadequate gestational weight gain was associated with increased odds of infant death. The increased risk remained after adjustment for gestational age, low birth weight, maternal age, maternal education, and maternal race. Among racial or ethnic subgroups, African American women with inadequate maternal weight gain were 1.3 times more likely than white women to have infant death.
There is a substantial and significant association between inadequate gestational weight gain and infant death.
Infant Mortality; Weight Gain; Pregnancy; Prenatal care; Institute of Medicine
To examine the Institute of Medicine (IOM) guidelines for gestational weight gain in adolescents.
Retrospective cohort using the Missouri Birth Certificate Registry. Included subjects were primiparous, singleton gestations, <20 years, delivered 24–44 weeks gestation. The exposure was defined as weight gain less than, within, or greater than IOM recommendations. Outcomes examined were small-for-gestational-age infants (SGA), large-for-gestational age infants (LGA), preterm delivery, infant death, preeclampsia, cesarean delivery, and operative vaginal delivery. The analysis was stratified by body mass index (BMI) category.
In any BMI category, inadequate weight gain was associated with increased odds of SGA, preterm delivery and infant death. When subjects gained more than IOM recommendations, SGA decreased with slight increases in LGA, preeclampsia, and cesarean delivery.
Adolescents should be counseled regarding adequate weight gain in pregnancy. Further research is necessary to determine if the IOM recommendations recommend enough weight gain in adolescents to optimize pregnancy outcomes.
Adolescent pregnancy; Gestational Weight Gain; body mass index
Sudden infant death syndrome (SIDS) is the unexpected death of an infant that remains unexplained after a thorough investigation of the circumstances, family history, paediatric investigation and complete autopsy. In Western society, it is the leading cause of post-neonatal death below 1 year of age. In the Netherlands, the SIDS incidence is very low, which offers opportunities to assess the importance of old and new environmental risk factors. For this purpose, cases were collected through pathology departments and the working group on SIDS of the Dutch Paediatrician Foundation. A total of 142 cases were included; these occurred after the parental education on sleeping position (1987), restricted to the international age criteria and had no histological explanation. Age-matched healthy controls (N = 2,841) came from a survey of the Netherlands Paediatric Surveillance Unit, completed between November 2002 and April 2003. A multivariate analysis was performed to determine the risk factors for SIDS, including sleeping position, antenatal maternal smoking, postnatal parental smoking, premature birth, gender, lack of breastfeeding and socio-economic status. Postnatal smoking was identified as an important environmental risk factor for SIDS (OR one parent = 2.5 [1.2, 5.0]; both parents = 5.77 [2.2, 15.5]; maternal = 2.7 [1.0, 6.4]; paternal = 2.4 [1.3, 4.5] ) as was prone sleeping (OR put prone to sleep = 21.5 [10.6, 43.5]; turned prone during sleep = 100 [46, 219]). Premature birth was also significantly associated with SIDS (OR = 2.4 [1.2, 4.8]).
Postnatal parental smoking is currently a major environmental risk factor for SIDS in the Netherlands together with the long-established risk of prone sleeping.
Sudden infant death; SIDS; Case–control study; Environmental risk factors; Prone sleeping; Parental smoking; Breastfeeding; Premature birth
Objectives To compare changes in inequalities in sudden infant death syndrome with other causes of infant mortality and stillbirth in Scotland, 1985-2008.
Design Retrospective cohort study.
Setting Scotland 1985-2008, analysed by four epochs of six years.
Participants Singleton births of infants with birth weight >500 g born at 28-43 weeks’ gestation.
Main outcome measures Sudden infant death syndrome, other causes of postneonatal infant death, neonatal death, and stillbirth. Odds ratios expressed as the association across the range of seven categories of Carstairs deprivation score.
Results The association between deprivation and the risk of all cause stillbirth and infant death varied between the four epochs (P=0.04). This was wholly explained by variation in the risk of sudden infant death syndrome (P<0.001 for interaction). Among women living in areas of low deprivation, there was a sharp decline in the rate of sudden infant death syndrome from 1990 to 1993. Among women living in areas of high deprivation, there was a slower decline in sudden infant death syndrome rates between 1992 and 2004. Consequently, the odds ratio for the association between socioeconomic deprivation and sudden infant death syndrome increased from 2.04 (95% confidence interval 1.53 to 2.72) in 1985-90, to 7.52 (4.62 to 12.25) in 1991-6, and 9.50 (5.46 to 16.53) in 1997-2002 but fell to 1.78 (0.87 to 3.65) in 2002-8. The interaction remained significant after adjustment for maternal characteristics.
Conclusion The rate of sudden infant death syndrome declined throughout Scotland in the early 1990s. The decline had a later onset and was slower among women living in areas of high deprivation, probably because of slower uptake of recommended changes in infant sleeping position. The effect was to create a strong independent association between deprivation and sudden infant death syndrome where one did not exist before.
It is unclear if it is safe for babies to bed share with adults. In Ireland 49% of sudden infant death syndrome (SIDS) cases occur when the infant is bed‐sharing with an adult.
To evaluate the effect of bed‐sharing during the last sleep period on risk factors for SIDS in Irish infants.
An 8 year (1994–2001) population based case control study of 287 SIDS cases and 831 controls matched for date, place of birth, and sleep period. Odds ratios and 95% confidence intervals were calculated by conditional logistic regression.
The risk associated with bed‐sharing was three times greater for infants with low birth weight for gestation (UOR 16.28 v 4.90) and increased fourfold if the combined tog value of clothing and bedding was ⩾10 (UOR 9.68 v 2.34). The unadjusted odds ratio for bed‐sharing was 13.87 (95% CI 9.58 to 20.09) for infants whose mothers smoked and 2.09 (95% CI 0.98 to 4.39) for non‐smokers. Age of death for bed‐sharing and sofa‐sharing infants (12.8 and 8.3 weeks, respectively) was less than for infants not sharing a sleep surface (21.0 weeks, p<0.001) and fewer bed‐sharing cases were found prone (5% v 32%; p = 0.001).
Risk factors for SIDS vary according to the infant's sleeping environment. The increased risk associated with maternal smoking, high tog value of clothing and bedding, and low z scores of weight for gestation at birth is augmented further by bed‐sharing. These factors should be taken into account when considering sleeping arrangements for young infants.
bed‐sharing; birth weight; maternal smoking; overheating; SIDS; sudden infant death syndrome
We examined the child-rearing environmental factors that affect the occurrence of sudden infant death syndrome (SIDS) using a nationwide survey. Infants who died due to SIDS between January 1996 and June 1997 in Japan were identified from death certificates. Controls of the same gender, birthplace, and birth months as the corresponding SIDS were chosen from birth certificates. Interviews of both cases and controls were undergone in January and February, 1998 by public health nurses. The following child-rearing factors exhibited a significant relationship with the occurrence of SIDS: Concerning the sleeping position, the prone position was associated with increased risk compared with the supine position, with an odds ratio of 3.02 (95% c.i. 2.07–4.65). Regarding the feeding method, artificial feeding alone demonstrated a higher risk than breast feeding alone, with an odds ratio of 4.92 (95% c.i. 2.78–9.63). With regard to smoking, infants with both parents who smoked exhibited a higher risk than infants where neither parent smoked, with an odds ratio of 3.50 (95% c.i. 1.74–8.32).
sudden infant death syndrome; child care practice; prone sleeping position; smoking; artificial feeding
Sudden infant death syndrome (SIDS) is the leading cause of death in infants between the ages of 1 and 12 months in developed countries. SIDS is by definition a diagnosis of exclusion, and its mechanism of action is unknown. The SIDS–Critical Diaphragm Failure (CDF) hypothesis postulates that the cause of death in SIDS is respiratory failure caused by CDF. Four principal risk factors contribute to CDF in young infants: undeveloped respiratory muscles, non-lethal infections, prone resting position, and REM sleep. Even relatively minor infections can cause an acute and significant reduction in diaphragm force generation capacity that in conjunction with other risk factors can precipitate CDF. CDF-induced acute muscle weakness leaves few, if any pathological marks on the affected tissue.Understanding the underlying mechanism of SIDS may help in formulating new approaches to child care that can help to further reduce the incidence of SIDS.
sudden infant death syndrome (SIDS); infection; diaphragm; pediatrics
Mortality from sudden infant death syndrome (SIDS, or cot death) in New Zealand has been high by international standards (4/1000 live births). Within New Zealand the rate is higher in Maori than in non-Maori (predominantly European infants) and higher in South Island than in North Island. The National Cot Death Prevention Programme aims to reduce the prevalence of four modifiable risk factors for SIDS, namely infants sleeping prone, maternal smoking, lack of breast feeding, and infants sharing a bed with another person. The aim of this study is to describe the total postneonatal and total SIDS mortality in New Zealand from 1986 to 1992. Official publications from 1986 to 1990 and preliminary death notifications for 1991 and 1992 were examined. Deaths from all causes in the postneonatal age group (28 days to 1 year) and the total number of deaths from SIDS irrespective of age decreased markedly in 1990 and has continued to decrease. This decrease occurred particularly in non-Maori groups, in South Island, and in the winter months. The proportion of infants sleeping in a prone position has decreased from 43% to less than 5%. This suggests that the prone position is causally related to SIDS. The mechanism appears to be related directly or indirectly to environmental temperature.
Sudden death (SD) in children is rarer than in adults. In the pediatric population, SD accounts for less than one tenth of deaths from all causes. SD in infants is a separate entity commonly termed "sudden infant death syndrome (SIDS)". Previous studies on SD in pediatric patients primarily focused on infants and showed that the incidence of SIDS was much lower in Asian countries than in Western ones. However, these differences diminished after educational campaigns such as the back to sleep act in the late 1980s to early 1990s. The incidence of SIDS from Western reports has decreased from 2.69 to around 0.5-0.24 per 1,000 live births. Beyond infancy, the annual incidence of SD ranges from 1.3 to 7.5 per 100,000. In 2009, two population-based studies, one from Taiwan and the other from the US, explored the epidemiological profile of SD in children. The child health care indexes of these two countries are similar, but the annual incidence of pediatric SD was 7.5 and 2.7 per 100,000 in the USA and Taiwan, respectively. The implications of ethic-related differences requires further confirmation. Around 40% of pediatric SD could be from cardiac causes, either diagnosed or undiagnosed. Risk stratification for cardiac SD and patient selection for implantable cardioverter-defibrillator (ICD) therapy are recommended. However, the adoption of ICD as primary prevention for SD in children is still a challenging issue. Early detection of undiagnosed cardiac risk may be facilitated by cardiac screening either in newborns or the school-age population to better manage the risk of SD. However, the efficacy of such screening remains still controversial.
Sudden death; Infant; Children
OBJECTIVE—To investigate the association between
altitude of residence and risk of sudden infant death syndrome (SIDS).
METHODS—A retrospective, case control study in the
Tyrol, Austria enrolled 99 infants with SIDS occurring between 1984 and
1994, and 136 randomly selected control cases. Data on pregnancy,
delivery, child care practice, and sociodemographic characteristics
including altitude of residence were collected with a standardised questionnaire.
RESULTS—The risk of SIDS increased gradually with
increasing altitude of residence. This relation remained independently
significant when the analysis was adjusted for gestational age, birth
weight, prenatal care, mother's age at delivery, educational level of parents, and cigarette smoking during pregnancy. The prone sleeping position emerged as an obligatory cofactor in this association. In the
whole of Austria, a similar trend of association emerged between the
average altitudes in the 99 political counties and the rates of SIDS.
CONCLUSIONS—This study identified altitude of
residence as a significant risk predictor of SIDS, primarily in
combination with the prone sleeping position. Respiratory disturbances,
reduced oxygen saturation, and lower temperatures at high altitude
might explain this association.
Objectives: To review the incidence and characteristics of preventable childhood deaths in an urban population in the UK and to determine whether the excess of preventable deaths seen previously in Asian girls still exists.
Design: A retrospective survey of childhood deaths from 1996–2002 classified in terms of preventability and compared with a previous study conducted 20 years earlier from 1976–82.
Setting: The city of Wolverhampton in the UK.
Main outcome measures: Deaths from all causes in children under the age of 5 years.
Results: There has been a reduction in the number of deaths in all age groups and from all causes. The postneonatal mortality rate fell from 6.5/1000 in 1976 to 3.1/1000 live births in 2002 largely because of the fall in the numbers of deaths caused by sudden infant death syndrome (SIDS). Preventable deaths are still associated with low birth weight (p<0.001) and poverty (unemployment and overcrowding in the earlier study (p<0.05) and with the Townsend score in this study (p<0.02)). There were fewer deaths among Asians and no female excess. There was a new category not seen in the previous study, deaths caused by homicide. The death rate for homicide in the first year of life was much higher in Wolverhampton (18.7/100 000) than in England and Wales (4.6/100 000).
Conclusions: Low birth weight and adverse socioeconomic conditions remain important factors associated with preventable deaths. There is no longer an increased risk of preventable death in Asian girls. The number of non-accidental deaths is a major cause for concern.
To determine cause and manner of death for consecutive infant deaths in the Aberdeen Area of the Indian Health Service (AAIHS) from 1998 to 2002 and to identify risk markers for infant mortality.
Infant deaths in the AAIHS were identified from four data sources: death certificates from the four states in the AAIHS, deaths reported by local IHS Service Units, from obituaries in local and regional newspapers, and deaths reported by area hospitals. Each infant death is then sent to the local IHS service unit for review, where data from the infant and mother's chart is extracted and recorded. Local community factors, birth and death certificates, and autopsy reports are collected. The case is then reviewed at the Perinatal Infant Mortality Review (PIMR) meeting and a cause and manner of death is assigned. Summary data for the cohort was examined and then compared by mortality category and three age-at-death groups.
Sudden infant death syndrome accounted for 33% of all infant deaths in the AAIHS. Prematurity was the second most prevalent cause-specific mortality category, accounting for 22% of all infant deaths. The authors found that infant mortality was surprisingly recurrent, with 32% of mothers of this infant having had a previous infant death.
The PIMR committee requires substantial resources to support a review committee with appropriate expertise and their travel. Participation of local IHS staff and tribal members provides an important cultural and community perspective for the review process. Quality improvement changes are currently being implemented. These include increasing data on substance use, mental health needs, and reviews of fetal deaths. The process of mortality review has been very helpful in public education in the AAIHS.