Showing papers on "Sudden infant death syndrome published in 2003"

Sudden death associated with short-QT syndrome linked to mutations in HERG.

Abstract: Background— Sudden cardiac death takes the lives of more than 300 000 Americans annually. Malignant ventricular arrhythmias occurring in individuals with structurally normal hearts account for a subgroup of these sudden deaths. The present study describes the genetic basis for a new clinical entity characterized by sudden death and short-QT intervals in the ECG. Methods and Results— Three families with hereditary short-QT syndrome and a high incidence of ventricular arrhythmias and sudden cardiac death were studied. In 2 of them, we identified 2 different missense mutations resulting in the same amino acid change (N588K) in the S5-P loop region of the cardiac I Kr channel HERG (KCNH2). The mutations dramatically increase I Kr , leading to heterogeneous abbreviation of action potential duration and refractoriness, and reduce the affinity of the channels to I Kr blockers. Conclusions— We demonstrate a novel genetic and biophysical mechanism responsible for sudden death in infants, children, and young adults caused by mutations in KCNH2. The occurrence of sudden cardiac death in the first 12 months of life in 2 patients suggests the possibility of a link between KCNH2 gain of function mutations and sudden infant death syndrome. KCNH2 is the binding target for a wide spectrum of cardiac and noncardiac pharmacological compounds. Our findings may provide better understanding of drug interaction with KCNH2 and have implications for diagnosis and therapy of this and other arrhythmogenic diseases.

Deaths: leading causes for 2001.

Abstract: OBJECTIVES This report presents final 2001 data on the 10 leading causes of death in the United States by age, race, sex, and Hispanic origin. Leading causes of infant, neonatal, and postneonatal death are also presented. This report supplements the annual report of final mortality statistics. METHODS Data in this report are based on information from all death certificates filed in the 50 States and the District of Columbia in 2001. Causes of death classified by the International Classification of Diseases, Tenth Revision are ranked according to the number of deaths assigned to rankable causes. RESULTS In 2001, the 10 leading causes of death were (in rank order) Diseases of heart; Malignant neoplasms; Cerebrovascular diseases; Chronic lower respiratory diseases; Accidents (unintentional injuries); Diabetes mellitus; Influenza and pneumonia; Alzheimer's disease; Nephritis, nephrotic syndrome and nephrosis; and Septicemia and accounted for nearly 80 percent of all deaths occurring in the United States. Differences in the rankings are evident by age, sex, race, and Hispanic origin. Leading causes of infant death for 2001 were (in rank order) Congenital malformations, deformations and chromosomal abnormalities; Disorders related to short gestation and low birth weight, not elsewhere classified; Sudden infant death syndrome; Newborn affected by maternal complications of pregnancy; Newborn affected by complications of placenta, cord and membranes; Respiratory distress of newborn; Accidents (unintentional injuries); Bacterial sepsis of newborn; Diseases of the circulatory system; and Intrauterine hypoxia and birth asphyxia. Important variation in the leading causes of infant death is noted for the neonatal and postneonatal periods.

Sleep Environment and the Risk of Sudden Infant Death Syndrome in an Urban Population: The Chicago Infant Mortality Study

Abstract: Objective. To examine risk factors for sudden infant death syndrome (SIDS) with the goal of reducing SIDS mortality among blacks, which continues to affect this group at twice the rate of whites. Methods. We analyzed data from a population-based case-control study of 260 SIDS deaths that occurred in Chicago between 1993 and 1996 and an equal number of matched living controls to determine the association between SIDS and factors in the sleep environment and other variables related to infant care. Results. The racial/ethnic composition of the study groups was 75.0% black; 13.1% Hispanic white; and 11.9% non-Hispanic white. Several factors related to the sleep environment during last sleep were associated with higher risk of SIDS: placement in the prone position (unadjusted odds ratio [OR]: 2.4; 95% confidence interval [CI]: 1.7–3.4), soft surface (OR: 5.1; 95% CI: 3.1–8.3), pillow use (OR: 2.5; 95% CI: 1.5–4.2), face and/or head covered with bedding (OR: 2.5; 95% CI: 1.3–4.6), bed sharing overall (OR: 2.7; 95% CI: 1.8–4.2), bed sharing with parent(s) alone (OR: 1.9; 95% CI: 1.2–3.1), and bed sharing in other combinations (OR: 5.4; 95% CI: 2.8–10.2). Pacifier use was associated with decreased risk (unadjusted OR: 0.3; 95% CI: 0.2–0.5), as was breastfeeding either ever (OR: 0.2; 95% CI: 0.1–0.3) or currently (OR: 0.2; 95% CI: 0.1–0.4). In a multivariate model, several factors remained significant: prone sleep position, soft surface, pillow use, bed sharing other than with parent(s) alone, and not using a pacifier. Conclusions. To lower further the SIDS rate among black and other racial/ethnic groups, prone sleeping, the use of soft bedding and pillows, and some types of bed sharing should be reduced.

Prevention and Management of Positional Skull Deformities in Infants

Abstract: Cranial asymmetry may be present at birth or may develop during the first few months of life. Over the past several years, pediatricians have seen an increase in the number of children with cranial asymme- try, particularly unilateral flattening of the occiput. This increase likely is attributable to parents following the American Academy of Pediatrics "Back to Sleep" posi- tioning recommendations aimed at decreasing the risk of sudden infant death syndrome. Although associated with some risk of deformational plagiocephaly, healthy young infants should be placed down for sleep on their backs. This practice has been associated with a dramatic de- crease in the incidence of sudden infant death syndrome. Pediatricians need to be able to properly diagnose skull deformities, educate parents on methods to proactively decrease the likelihood of the development of occipital flattening, initiate appropriate management, and make referrals when necessary. This report provides guidelines for the prevention, diagnosis, and management of posi- tional skull deformity in an otherwise normal infant without evidence of associated anomalies, syndromes, or spinal disease.

Predictors of psychosocial distress after suicide, SIDS and accidents.

Abstract: This article compares the outcome and predictors of psychosocial distress of parents bereaved by young suicides, sudden infant death syndrome (SIDS), and child accidents One objective is to explore whether suicide bereavement is more difficult for those left behind than other forms of bereavement Data have been collected from 140 families, consisting of 232 parents, by the use of the Impact of Event Scale, the General Health Questionnaire, and the Inventory of Traumatic Grief Qualitative aspects of bereavement are assessed by in-depth interviews with family members from 40 families The results show that the similarities between the samples on outcome and predictors are more striking than the differences, which is explained by the common traumatic aspect of unexpected and violent deaths One and a half years post-loss, 57-78% of the survivors scored above the cut-off levels for traumatic grief reactions Although no significant differences are found between survivors of suicide and accidents, both grou

Smoking and sudden infant death syndrome

Abstract: Assessment of the causation relationship between two phenomena requires the demonstration of an epidemiological association, a temporal and asymmetric sequence, and a biological gradient and identification of the biological mechanism(s). All epidemiological studies on sudden infant death syndrome (SIDS) and smoking have encountered major bias and difficult data interpretation but they all have estimated that maternal smoking caused a 2 to 3-fold increased risk of SIDS. Nicotine may interact with non-neuronal nicotinic receptors in the lung, peripheral nicotinic cholinergic and adrenergic chemoreceptors, and brainstem nuclei and has been largely studied. More accurate knowledge concerning the biochemistry and specific features of nicotinic receptors will be useful to explain the way nicotine alters breathing at rest and during hypoxia. Uncertainty about the casual relationship in no way means the fight against smoking is not warranted.

Serotonergic brainstem abnormalities in Northern Plains Indians with the sudden infant death syndrome.

Abstract: The rate of the sudden infant death syndrome (SIDS) among American Indian infants in the Northern Plains is almost 6 times higher than in U.S. white infants. In a study of infant mortality among Northern Plains Indians, we tested the hypothesis that receptor binding abnormalities to the neurotransmitter serotonin (5-HT) in SIDS cases, compared with autopsied controls, occur in regions of the medulla oblongata that contain 5-HT neurons and that are critical for the regulation of cardiorespiration and central chemosensitivity during sleep, i.e. the medullary 5-HT system. Tritiated-lysergic acid diethylamide binding to 5-HT(1A-D) and 5-HT2 receptors was measured in 19 brainstem nuclei in 23 SIDS and 6 control infants using tissue receptor autoradiography. Binding in the arcuate nucleus, a part of the medullary 5-HT system along the ventral surface, in the SIDS infants (mean age-adjusted binding 7.1 +/- 0.8 fmol/mg tissue, n = 23) was significantly lower than in controls (mean age-adjusted binding 13.1 +/- 1.6 fmol/mg tissue, n = 5) (p = 0.003). Binding also demonstrated significant diagnosis x age interactions (p < 0.04) in 4 other nuclei that are components of the 5-HT system. These data suggest that medullary 5-HT dysfunction can lead to sleep-related, sudden death in affected SIDS infants, and confirm the same binding abnormalities reported by us in a larger dataset of non-American Indian SIDS and control infants. This study also links 5-HT abnormalities in the arcuate nucleus with exposure to adverse prenatal exposures, i.e. cigarette smoking (p = 0.011) and alcohol (p = 0.075), during the periconceptional period or throughout pregnancy. Prenatal exposure to cigarette smoke and/or alcohol may contribute to abnormal fetal medullary 5-HT development in SIDS infants.

Defining the Sudden Infant Death Syndrome

Abstract: Sudden infant death syndrome (SIDS) is a term that was first proposed in 1969 for a distinctive subgroup of unexpected infant deaths that occur during the postneonatal period with relatively consistent clinical, epidemiological, and pathological features. This term played an important role by focusing attention on a major category of postneonatal infant death, providing support to grieving families, and diminishing the guilt and blame characteristic of these deaths. Unfortunately, the application of this term has become increasingly controversial. Some have applied it too liberally, and others not at all. According to the definition proposed in 1969, despite slight changes suggested in 1989, SIDS remains a diagnosis of exclusion. Although this syndrome has several distinctive features, including age distribution and apparent occurrence during sleep, there has been reluctance to include these features in the definition. The problems created by the lack of an adequate definition are discussed. A 2-tiered approach is suggested, with a more general definition intended primarily for case management and death administration, and a more restrictive one intended primarily for research purposes, which distinguishes those deaths closely fitting the classic SIDS profile from those with one or more less typical features.

Long QT syndrome and anaesthesia

Abstract: Long QT syndrome (LQTS) is an arrhythmogenic cardiovascular disorder resulting from mutations in cardiac ion channels. LQTS is characterized by prolonged ventricular repolarization and frequently manifests itself as QT interval prolongation on the electrocardiogram (ECG). The age at presentation varies from in utero to adulthood. The majority of symptomatic events are related to physical activity and emotional stress. Although LQTS is characterized by recurrent syncope, cardiac arrest, and seizure-like episodes, only about 60% of patients are symptomatic at the time of diagnosis. 3 The clinical features of LQTS result from a peculiar episodic ventricular tachyarrhythmia called ‘torsade de pointes’. ‘Twisting of the points’ describes the typical sinusoidal twisting of the QRS axis around the isoelectric line of the ECG. Usually torsade de pointes start with a premature ventricular depolarization, followed by a compensatory pause. The next sinus beat often has a markedly prolonged QT interval and abnormal T wave. This is followed by a ventricular tachycardia that is characterized by variation in the QRS morphology, and a constantly changing R-R interval (Fig. 1). The ‘short-long-short’ cycle length sequence heralding torsade de pointes is a hallmark of LQTS. Commonly, the episode of torsade de pointes is self-terminating, producing a syncopal episode or pseudoseizure, secondary to the abrupt decrease in cerebral blood flow. The majority of episodes of sudden death in LQTS result from ventricular fibrillation triggered by torsade de pointes, although the mechanism of this deterioration is unknown. Traditionally, LQTS has been classified as either familial (inherited) or acquired. However, it is likely that many patients with previously labelled acquired LQTS carry a silent mutation in one of the genes responsible for congenital LQTS. 22 119 The evidence for this hypothesis has been gradually emerging over the past few years. It is important for anaesthetists to be aware of this concept, as it means that a much higher proportion of the general population may be affected by asymptomatic mutations in genes encoding cardiac ion channels than was thought previously. The prevalence of LQTS in developed countries may be as high as 1 per 1100‐3000 of the population. 32 119 About 30% of congenital LQTS carriers have an apparently normal phenotype, and thus a normal QT interval, and remain undiagnosed until an initiating event. 105 Fatal arrhythmias associated with primary electrical disease of the heart such as the Brugada and LQTS, probably account for 19% of sudden deaths in children between 1 and 13 yr of age, and 30% of sudden deaths that occur between 14 and 21 yr of age. 10 Furthermore, there is a strong association between prolonged corrected QT interval (QTc) in the first week of life and risk of sudden infant death syndrome. 86

Incomplete arousal processes in infants who were victims of sudden death.

Abstract: Infants who became victims of sudden infant death syndrome (SIDS) aroused less from sleep than control infants. This study was conducted to determine the characteristics of arousal from sleep of infants who eventually died of SIDS. Sixteen infants were monitored some days or weeks before they died of SIDS. Their polygraphic sleep recordings were compared with those of matched control infants. Arousals were scored as subcortical activation (incomplete arousals) or cortical arousal (complete arousals). Cortical arousals were significantly less frequent in the victims who would succumb to SIDS in the future than in the control infants during both REM and non-REM sleep (p = 0.039). The frequency (p = 0.017) and duration (p = 0.005) of subcortical activation were significantly greater in the infants who died of SIDS than in the control infants during REM sleep. Compared with the control infants, the infants who later died of SIDS had more frequent subcortical activation in the first part of the night, between ...

Infant mortality statistics from the 2001 period linked birth/infant death data set.

Abstract: Objectives This report presents 2001 period infant mortality statistics from the linked birth/infant death data set (linked file) by a variety of maternal and infant characteristics. Methods Descriptive tabulations of data are presented and interpreted. Results Infant mortality rates ranged from 3.2 per 1,000 live births for Chinese mothers to 13.3 for black mothers. Among Hispanics, rates ranged from 4.2 for Cuban mothers to 8.5 for Puerto Rican mothers. Infant mortality rates were higher for those infants whose mothers were born in the 50 States and the District of Columbia, were unmarried, or smoked during pregnancy. Infant mortality was also higher for male infants, multiple births, and infants born preterm or at low birthweight. The three leading causes of infant death--Congenital malformations, low birthweight, and Sudden infant death syndrome (SIDS)--taken together accounted for 44 percent of all infant deaths. Cause-specific mortality rates varied considerably by race and Hispanic origin. For infants of black mothers, the cause-specific infant mortality rate for low birthweight was nearly four times that for infants of white mothers. Between 1995 and 2001, the overall infant mortality rate declined by 10.5 percent; significant declines ranged from 8.2 percent for infants of non-Hispanic black mothers to 14.3 percent for infants of Hispanic mothers. The SIDS rate declined by 11 percent from 2000 to 2001. For infants of black and American Indian mothers, the SIDS rates were 2.2 and 2.8 times that for non-Hispanic white mothers.

The anatomy of a disparity in infant mortality.

Abstract: ▪ Abstract This article suggests that while disparities in infant mortality have been longstanding, the mechanisms of disparity creation are undergoing intense change. This dynamic character is explored by first developing an analytic model that examines the interaction between social factors and the public health and clinical capacity to intervene. Disparities in infant mortality are then broken down into their component parts and linked to specific arenas of intervention. Disparities in postneonatal mortality are being shaped by differential access to interventions designed to prevent infant death from congenital anomalies and the Sudden Infant Death Syndrome. Disparities in neonatal mortality are primarily determined by factors that influence the birthrate of extremely premature infants and access to specialized obstetrical and pediatric care. This analysis suggests that the epidemiology and social meaning of disparities in infant mortality are intensely dynamic and increasingly reflect the interaction...

Determinants of Nonsynostotic Plagiocephaly: A Case-Control Study

Abstract: Objective. There has been a large in- crease in reported cases of nonsynostotic plagiocephaly in infants since the adoption of supine sleeping recom- mendations to prevent sudden infant death syndrome. The objective of this study was to identify and quantify the determinants of nonsynostotic plagiocephaly in in- fants. Methods. One hundred infants who received a diag- nosis of having nonsynostotic plagiocephaly were re- cruited as case patients and compared with 94 control subjects who were selected from a citywide database of infants. The infants all were aged between 2 and 12 months. Information concerning sociodemographic vari- ables, obstetric factors, infant factors, and infant care practices was obtained by parental interview.

Respiratory health effects of exposure to environmental tobacco smoke

Abstract: Tobacco smoke is a major component of indoor air pollution. Exposure to environmental tobacco smoke (ETS) is prevalent worldwide despite growing awareness of its adverse health effects on non-smokers. ETS contains the same toxic substances as identified in mainstream tobacco smoke. Cotinine (a metabolite of nicotine) can be measured in urine and serum of non-smokers exposed to ETS and reflects the degree of exposure. In children, exposure to ETS leads to reduced lung function, increased risk of lower respiratory tract illnesses, acute exacerbation of asthma resulting in hospitalization, increased prevalence of non-allergic bronchial hyperresponsiveness, increased risk for sudden infant death syndrome (SIDS) and possibly increased risk for asthma. Exposure to ETS is responsible for excess cost to the family's financial resources and demands on health services. In adults, exposure to ETS is associated with increased risk of lung cancer, particularly in those with high exposure and acute and chronic respiratory symptoms that improve after the cessation of exposure. Healthcare providers should advocate for non-smokers' rights in the community and support legislation to limit tobacco exposure.

Characterization of successful and failed autoresuscitation in human infants, including those dying of SIDS.

Abstract: Our purpose was to identify and further characterize physiologic mechanisms relevant to autoresuscitation from hypoxic apnea in infants dying suddenly and unexpectedly We studied cardiorespiratory recordings of 24 infants (age range, 08-21 months) who died suddenly while being monitored at home These recordings were analyzed for features indicated by studies in animal models to be characteristic of hypoxic gasping, and of recovery from bradycardia and apnea associated with gasping (eg, autoresuscitation) Findings in 5 infants diagnosed as having sudden infant death syndrome were compared with 6 non-SIDS infants whose deaths resulted from other conditions Additionally, we studied 15 healthy infants during sleep, using home monitor and other respiratory recording techniques, in order to obtain comparison data We found in recordings from 23 of 24 subjects that hypoxic gasps with characteristic features occurred immediately preceding death A unique pattern of complex, closely spaced gasps ("double" or "triple" gasps) was present in many subjects Evidence of partially successful autoresuscitation closely following one or more gasps occurred in 11 subjects, while another 4 had evidence of complete autoresuscitation with return of normal heart rate and resolution of apnea on one or more occasions Significant differences between SIDS infants and those dying from other causes included increased occurrence of complex gasps and decreased occurrence of partial or complete autoresuscitation in the SIDS infants The non-SIDS cases were different from the SIDS cases in that only one had "double" gasps (n = 7), while none had "triple" gasps, as compared with 4 out of 5 SIDS cases with these patterns (P < 005, chi-square) Also, in contrast with the SIDS cases, more of the cases with specific postmortem diagnoses had evidence of partial (5 out of 6 cases) or complete (1 out of 6 cases) autoresuscitation (P < 005, chi-square) We conclude that partial or complete autoresuscitation by gasping is not uncommon in moribund infants during the first year of life Failure of autoresuscitation mechanisms other than failure to initiate gasping may be characteristic of infants dying of SIDS Some SIDS infants appear to be different from infants dying with other diagnoses with respect to efficacy and characteristics of hypoxic gasping

Infantile spinal muscular atrophy with respiratory distress type 1 (SMARD1).

Abstract: Autosomal recessive spinal muscular atrophy with respiratory distress type 1 (SMARD1) is the second anterior horn cell disease in infants in which the genetic defect has been defined. SMARD1 results from mutations in the gene encoding the immunoglobulin mu-binding protein 2 (IGHMBP2) on chromosome 11q13. Our aim was to review the clinical features of 29 infants affected with SMARD1 and report on 26 novel IGHMBP2 mutations. Intrauterine growth retardation, weak cry, and foot deformities were the earliest symptoms of SMARD1. Most patients presented at the age of 1 to 6 months with respiratory distress due to diaphragmatic paralysis and progressive muscle weakness with predominantly distal lower limb muscle involvement. Sensory and autonomic nerves are also affected. Because of the poor prognosis, there is a demand for prenatal diagnosis, and clear diagnostic criteria for infantile SMARD1 are needed. The diagnosis of SMARD1 should be considered in infants with non-5q spinal muscular atrophy, neuropathy, and muscle weakness and/or respiratory distress of unclear cause. Furthermore, consanguineous parents of a child with sudden infant death syndrome should be examined for IGHMBP2 mutations.

Sudden infant death syndrome: association with a promoter polymorphism of the serotonin transporter gene.

Abstract: Serotonergic receptor binding in the arcuate nucleus, n. raphe obscurus, and other medullary regions is decreased in sudden infant death syndrome (SIDS) cases. Further, a variable tandem repeat sequence polymorphism in the promoter region of the serotonin transporter protein (5-HTT) gene has recently been associated with risk of SIDS in a Japanese cohort. This polymorphism differentially regulates 5-HTT expression, with the long allele (L), the SIDS-associated allele, being a more effective promoter than the short allele (S). We therefore investigated the 5-HTT promoter polymorphism in a cohort of 87 SIDS cases (43 African American and 44 Caucasian) and gender/ethnicity-matched controls. Significant positive associations were found between SIDS and the 5-HTT genotype distribution (P = 0.022), specifically with the L/L genotype (P = 0.048), and between SIDS and the 5-HTT L allele (P = 0.005). There was also a significant negative association between SIDS and the S/S genotype (P = 0.011). The comparisons were repeated in the African American and Caucasian subgroups. The data patterns were consistent in the subgroups, i.e., the L/L genotype and L allele were increased in the cases, but not all subgroup comparisons were statistically significant. These results indicate a relationship between SIDS and the L allele of the 5-HTT gene in African Americans and Caucasians, and if confirmed, will provide an important tool for identifying at-risk individuals and estimating the risk of recurrence. © 2003 Wiley-Liss, Inc.

Infant Sleeping Position and the Risk of Sudden Infant Death Syndrome in California, 1997–2000

Abstract: To assess the association between infant sleeping position and risk of sudden infant death syndrome (SIDS) in an ethnically diverse US population, the authors conducted a population-based case-control study in 11 counties in California from May 1997 through April 2000. The authors conducted in-person interviews with the mothers of 185 SIDS cases and 312 randomly selected race/ethnicity- and age-matched controls to collect information on sleeping positions. Infants who had last been put down to sleep in the prone or side position were at greater risk of SIDS than were infants who had last been put down on their backs (adjusted odds ratio (AOR) = 2.6 (95% confidence interval (CI): 1.5, 4.5) and AOR = 2.0 (95% CI: 1.2, 3.4) for the prone and side positions, respectively). The risk of SIDS was especially high for an unstable side position in which an infant was placed on its side and found prone (AOR = 8.7, 95% CI: 3.3, 22.7). Infants who were usually placed on their backs to sleep but had last been put down in the prone or side position (an unaccustomed position) had a significantly high risk of SIDS (AOR = 8.2 (95% CI: 2.6, 26.0) and AOR = 6.9 (95% CI: 2.3, 20.6) for the prone and side positions, respectively). Infants placed in an unaccustomed prone or side sleeping position had a higher risk of SIDS than infants who were always placed prone or on the side.

Very-Long-Chain Acyl-Coenzyme A Dehydrogenase Deficiency in Mice

Abstract: Fatty acid oxidation (FAO) defects are inborn errors of metabolism clinically associated with cardiomyopathy and sudden infant death syndrome (SIDS). FAO disorders often present in infancy with myocardial dysfunction and arrhythmias after exposure to stresses such as fasting, exercise, or intercurrent viral illness. It is uncertain whether the heart, in the absence of stress, is normal. We generated very-long-chain acyl-coenzyme A dehydrogenase (VLCAD)-deficient mice by homologous recombination to define the onset and molecular mechanism of myocardial disease. We found that VLCAD-deficient hearts have microvesicular lipid accumulation, marked mitochondrial proliferation, and demonstrated facilitated induction of polymorphic ventricular tachycardia, without antecedent stress. The expression of acyl-CoA synthase (ACS1), adipophilin, activator protein 2, cytochrome c, and the peroxisome proliferator activated receptor gamma coactivator-1 were increased immediately after birth, preceding overt histological lipidosis, whereas ACS1 expression was markedly downregulated in the adult heart. We conclude that mice with VLCAD deficiency have altered expression of a variety of genes in the fatty acid metabolic pathway from birth, reflecting metabolic feedback circuits, with progression to ultrastructural and physiological correlates of the associated human disease in the absence of stress.

Factors relating to the infant’s last sleep environment in sudden infant death syndrome in the Republic of Ireland

Abstract: Aim: To identify risk factors for sudden infant death syndrome (SIDS) in the sleeping environment of Irish infants. Methods: A five year population based case-control study with parental interviews conducted for each case and three controls matched for age, place of birth, and last sleep period. A total of 203 SIDS cases and 622 control infants born 1994–98 were studied. Results: In a multivariate analysis, co-sleeping significantly increased the risk of SIDS both as a usual practice (adjusted OR 4.31; 95% CI 1.07 to 17.37) and during the last sleep period (adjusted OR 16.47; 95% CI 3.73 to 72.75). The associated risk was dependent on maternal smoking (OR 21.84; 95% CI 2.27 to 209.89), and was not significant for infants who were ⩾20 weeks of age (OR 2.63; 95% CI 0.49 to 70.10) or placed back in their own cot/bed to sleep (OR 1.07; 95% CI 0.21 to 5.41). The use of pillows, duvets, and bedding with tog value ⩾10 were not significant risk factors when adjusted for the effects of confounding variables, including maternal smoking and social disadvantage. However, the prone sleeping position remains a significant SIDS risk factor, and among infants using soothers, the absence of soother use during the last sleep period also significantly increased the SIDS risk (OR 5.83; CI 2.37 to 14.36). Conclusion: Co-sleeping should be avoided in infants who are <20 weeks of age, or whose mothers smoked during pregnancy. The prone position remains a factor in some SIDS deaths, and the relation between soother use and SIDS is a complex variable requiring further study.

Sudden Infant Death Syndrome: Overview and Update

Abstract: The past decade and a half has seen marked changes in the epidemiology of sudden infant death syndrome (SIDS). The avoidance of certain risk factors such as sleeping prone and cigarette smoke exposure has resulted in the death rate falling dramatically. Careful evaluation of environmental factors and endogenous characteristics has led to a greater understanding of the complexities of the syndrome. The development and implementation of death scene and autopsy protocols has led to standardization in approaches to unexpected infant deaths with increasing diagnoses of accidental asphyxia. Despite these advances, there is still confusion surrounding the diagnosis, with deaths being attributed to SIDS in many communities and countries where death scene investigations and autopsies have not been conducted. The following review provides a brief overview of the historical background, epidemiology, pathology, and pathogenesis of SIDS. Contentious issues concerning the diagnosis and current problems are discussed. Despite calls to abandon the designation, SIDS remains a viable term for infants who die in their sleep with no evidence of accident, inflicted injury, or organic disease after a full investigation has been conducted according to standard guidelines.

Addressing parental smoking in pediatrics and family practice: a national survey of parents.

Abstract: Background. Parental smoking has been associated with increased rates of sudden infant death syndrome, low birth weight, otitis media, asthma, and decreased lung growth. No prior parent surveys have assessed national rates of screening and counseling for parental tobacco use in the context of their child’s visit to primary care. Objective. To assess and compare rates of pediatrician and family practitioner screening and counseling for parental smoking. Design/Methods. Data were collected by telephone survey of households from July to September 2001. The sample is weighted by race and gender based on 1999 US Census estimates to be representative of the US population. Results. Of 3566 eligible respondents contacted, 3002 (84%) completed surveys; 902 of those were parents who had a child seen by a pediatrician (62%) or family practitioner (38%) in the past year. About half of all parents who visited a pediatrician or family practitioner reported that they had been asked about household member smoking status (52% vs 48%). More parents who visited pediatricians had been asked if they had rules prohibiting smoking in the home than those who visited family practitioners (38% vs 29%). Of 190 (21%) parents who were smokers, fewer than half reported being counseled by either specialty about dangers of second-hand smoke (41% vs 33%) or risks of modeling smoking behavior (31% vs 28%). Similarly, fewer than half of parental smokers received advice to quit (36% vs 45%). Conclusion. Overall rates of screening and counseling for parental smoking in pediatric and family practice are low. Despite some differences between specialties, significant opportunities exist to improve tobacco control activities in primary care settings that serve children.

Association of the serotonin transporter gene with sudden infant death syndrome: A haplotype analysis

Abstract: Serotonergic receptor binding in the arcuate nucleus, n. raphe obscurus, and other medullary regions is decreased in sudden infant death syndrome (SIDS) cases. Further, an insertion/deletion polymorphism in the promoter region of the serotonin transporter protein (5-HTT) gene has recently been associated with risk of SIDS. This polymorphism differentially regulates 5-HTT expression, with the long allele (L), the SIDS-associated allele, being a more effective promoter than the short allele (S). To further elucidate the role of the 5-HTT gene in SIDS, we investigated the 5-HTT intron 2 polymorphism, which also differentially regulates 5-HTT expression with the 12 repeat allele being the more effective promoter. In a cohort of 90 SIDS cases (44 African-American and 46 Caucasian) and gender/ethnicity-matched controls, significant positive associations were found between SIDS and the intron 2 genotype distribution (P-value = 0.041) among African-American SIDS vs. African-American controls, specifically with the 12/12 genotype (P-value = 0.03), and with the 12 repeat allele (P-value=0.018). The frequency of the 12/12 genotype and 12-repeat allele was significantly different (P < 0.001) between the African-American and Caucasian SIDS cases. Furthermore, the promoter and intron 2 loci were in significant linkage disequilibrium, and the L-12 haplotype was significantly associated with SIDS in the African-American (P = 0.002) but not Caucasian (P = 0.117) subgroups. These results indicate a relationship between SIDS and the 12-repeat allele of the intron 2 variable number tandem repeat of the 5-HTT gene in African-Americans, and a significant role of the haplotype containing the 12-repeat allele and the promoter L-allele in defining SIDS risk in African-Americans. These data, if confirmed in larger studies, may begin to explain the differences in SIDS incidence by ethnicity, suggest a role for levels of 5-HTT expression in generation of SIDS susceptibility, and provide an important tool for identifying at-risk individuals and estimating the risk of recurrence. © 2003 Wiley-Liss, Inc.

Vascular endothelial growth factor in the cerebrospinal fluid of infants who died of sudden infant death syndrome: evidence for antecedent hypoxia.

Abstract: Objectives. Recurrent hypoxemia has been proposed as an important pathophysiological mechanism underlying sudden infant death syndrome (SIDS). However, conflicting results emerged when xanthines were used as markers for hypoxia. The vascular endothelial growth factor (VEGF) gene is highly sensitive to changes in tissue partial oxygen tension, and changes in genomic and protein expression occur even after changes in oxygenation within the physiologic range. Methods. For determining whether hypoxia precedes SIDS, VEGF levels were measured using an enzyme-linked immunosorbent assay in the cerebrospinal fluid (CSF) of 51 SIDS infants and in 33 additional control infants who died of an identifiable cause. In addition, 6 rats that had a chronically implanted catheter in the lateral ventricle were exposed to a short hypoxic challenge, and VEGF concentrations were measured in CSF at various time points for 24 hours. Another set of 6 rats were killed with a pentobarbital overdose, and VEGF CSF levels were obtained at different time points after death. Results. Mean VEGF concentrations in CSF were 308.2 ± 299.1 pg/dL in the SIDS group and 85.1 ± 82.9 pg/dL in those who died of known causes. Mean postmortem delay averaged 22 hours for both groups. In rat experiments, hypoxic exposures induced time-dependent increases in VEGF, peaking at 12 hours and returning to baseline at 24 hours. Postmortem duration in the animals was associated with gradual increases in VEGF that reached significance only at 36 hours. Conclusions. We conclude that VEGF CSF concentrations are significantly higher in infants who die of SIDS. We postulate that hypoxia is a frequent event that precedes the sudden and unexpected death of these infants.

Racial disparity and modifiable risk factors among infants dying suddenly and unexpectedly.

Abstract: Background. Racial disparity in rates of death attributable to sudden infant death syndrome (SIDS) has been observed for many years. Despite decreased SIDS death rates following the “Back to Sleep” intervention in 1994, this disparity in death rates has increased. The prone sleep position, unsafe sleep surfaces, and sharing a sleep surface with others (bedsharing) increase the risk of sudden infant death. The race-specific prevalence of these modifiable risk factors in sudden unexpected infant deaths-including SIDS, accidental suffocation (AS), and cause of death undetermined (UD)—has not been investigated in a population-based study. Death rates attributable to AS and UD are also higher in African Americans (AAs) than in other races (non-AA). The potential contribution of unsafe sleep practices to this overall disparity in death rates is uncertain. Objective. The objective of this study was to compare death rates attributable to SIDS and related causes of death (AS and UD) in AA and non-AA infants and the prevalence of unsafe sleep practices at time of death. Our hypothesis was that there is a large racial disparity in these modifiable risk factors at the time of death, and that public awareness of this could lead to improved intervention strategies to reduce the disparity in death rates. Methods. In this population-based study, we retrospectively reviewed death-scene information and medical examiners’ investigations of deaths in St Louis City and County between January 1, 1994, and December 31, 1997. The deaths of all infants Results. The deaths of 119 infants were studied (81 AA and 38 non-AA). SIDS rates were much higher in AA than non-AA infants (2.08 vs 0.65 per 1000 live births), as was the rate of AS (0.47 vs 0.06). There was a trend for increased deaths diagnosed as UD in AA infants (0.36 vs 0.06). Bedsharing deaths were nearly twice as common in AAs (67.1% vs 35.1% of deaths), as were deaths on nonstandard sleep surfaces (79.0% vs 46.0%). Forty-nine percent (49.1%) of all infants who died while bedsharing were found on their backs or sides compared with 20.4% of infants who were not bedsharing. Overall, the fraction of infants found in these nonprone positions was not different for AA infants and non-AA infants (43.3% vs 38.5%). In AA and non-AA infants, factors that greatly increase the risk of bedsharing, such as sofa sharing or all-night bedsharing, were present in all or many bedsharing deaths. Conclusion. Among AA infants dying suddenly and unexpectedly, the high prevalence of nonstandard bed use and bedsharing may underlie, in part, their increased death rates. Public health messages tailored for the AA community have stressed first and foremost using nonprone sleep positions. The observation that there was no difference between AA and non-AA infants in position found at death suggests that racial disparity in sleep position is not the most important contributor to racial disparity in death rates. The finding that more infants died on their back or side while bedsharing than otherwise suggests that these sleep positions are less protective when associated with bedsharing. We conclude that public health information tailored for the AA community should give equal emphasis to risks and alternatives to bedsharing as to avoidance of the prone position.

Infants with bilirubin levels of 30 mg/dL or more in a large managed care organization.

Abstract: OBJECTIVE To describe the incidence, etiology, treatment, and outcome of newborns with total serum bilirubin (TSB) levels >or=30 mg/dL (513 micro mol/L). DESIGN Population-based case series. SETTING Eleven Northern California Kaiser Permanente Medical Care Program hospitals and 1 affiliated hospital. PATIENTS Eleven infants with TSB levels of >or=30 mg/dL in the first 30 days after birth, identified using computer databases from a cohort of 111,009 infants born 1995-1998. OUTCOME MEASURES Clinical data from the birth hospitalization, rehospitalization, and outpatient visits in all infants; psychometric testing at age 5 (N = 3), neurologic examinations by child neurologists at age 5 (N = 3), or primary care providers (N = 7; mean age: 2.2 years); Parent Evaluation of Developmental Status (N = 8; mean age: 4.2 years). RESULTS Maximum TSB levels of the 11 infants ranged from 30.7 to 45.5 mg/dL (525 micro mol/L to 778 micro mol/L; mean: 34.9 mg/dL [597 micro mol/L]). Four were born at 35 to 36 weeks gestation, and 7 were exclusively breastfed. Two had apparent isoimmunization; the etiology for the other 9 remained obscure, although only 4 were tested for glucose-6-phosphate dehydrogenase deficiency and 1 was bacteremic. None had acute neurologic symptoms. All received phototherapy and 5 received exchange transfusions. One infant died of sudden infant death syndrome; there was no kernicterus at autopsy. Two were lost to follow-up but were neurologically normal when last seen for checkups at 18 and 43 months. One child was receiving speech therapy at age 3. There were no significant parental concerns or abnormalities in the other children. CONCLUSIONS In this setting, TSB levels >or=30 mg/dL were rare and generally unaccompanied by acute symptoms. Although we did not observe serious neurodevelopmental sequelae in this small sample, additional studies are required to quantify the known, significant risk of kernicterus in infants with very high TSB levels.

Child mortality, socioeconomic position, and one-parent families: independent associations and variation by age and cause of death

Abstract: Background Although the association between child mortality and socioeconomic status is well established, it is unclear whether child mortality differences by socioeconomic position are present at all ages. The association of one-parent families with mortality, and whether any such association is due to associated low socioeconomic position, is also not clear. Methods In all, 480 of 693 (69%) 0-14 year old deaths during 1991-1994 were linked to 1991 census records. Analyses were weighted to adjust for potential linkage bias. Results There was approximately twofold higher mortality among the lowest compared with the highest socioeconomic categories of education, income, car access, and neighbourhood deprivation. Occupational class differences were weaker. These socioeconomic differences in mortality were strongest among infants (particularly sudden infant death syndrome [SIDS] mortality), but similar across other age groups (1-4, 5-9, and 10-14 years). The socioeconomic differences were of a similar magnitude for unintentional injury, cancer, congenital, and other deaths. Multivariable analyses demonstrated persistent independent associations of education, income, car access, and neighbourhood deprivation with mortality. Rate ratios (adjusted for age and ethnicity) for one-parent families compared with two-parent or other families were 1.2 (95% CI: 1.0, 1.5) and 1.8 (95% CI: 1.2, 2.5) for all-cause and unintentional injury mortality, respectively. Further adjustment for socioeconomic factors reduced these associations to 0.8 (95% CI: 0.6, 1.2) and 1.2 (95% CI: 0.7, 2.2), respectively. Conclusions There does not appear to be notable variation in relative risk terms of socioeconomic differences in child mortality by age or cause of death. Any association of one-parent families with child mortality is due to associated low socioeconomic position.