SIDS risk factors and factors associated with prone sleeping in Sweden

Risk of Sudden Infant Death Syndrome Among Siblings of Children Who Died of Sudden Infant Death Syndrome in Denmark

IMPORTANCE

Sudden infant death syndrome (SIDS) remains a leading cause of death during the first year of life. The etiology of SIDS is complex and remains largely unknown.

OBJECTIVE

To evaluate whether siblings of children who died of SIDS have a higher risk of SIDS compared with the general pediatric population.

DESIGN, SETTING, AND PARTICIPANTS

This register-based cohort study used Danish nationwide registers. Participants were all infants (<1 year) in Denmark between January 1, 1978, and December 31, 2016, including siblings of children who died of SIDS. Siblings were followed up from the index cases' date of SIDS, date of birth, or immigration, whichever came first, and until age 1 year, emigration, developing SIDS, death, or study end. The median (IQR) follow-up was 1 (1-1) year. Data analysis was conducted from January 2017 to October 2022.

MAIN OUTCOMES AND MEASURES

Standardized incidence ratios (SIRs) of SIDS were calculated with Poisson regression models relative to the general population.

RESULTS

In a population of 2 666 834 consecutive births (1 395 199 [52%] male), 1540 infants died of SIDS (median [IQR] age at SIDS, 3 [2-4] months) during a 39-year study period. A total of 2384 younger siblings (cases) to index cases (first sibling with SIDS) were identified. A higher rate of SIDS was observed among siblings compared with the general population, with SIRs of 4.27 (95% CI, 2.13-8.53) after adjustment for sex, age, and calendar year and of 3.50 (95% CI, 1.75-7.01) after further adjustment for mother's age (<29 years vs ≥29 years) and education (high school vs after high school).

CONCLUSIONS AND RELEVANCE

In this nationwide study, having a sibling who died of SIDS was associated with a 4-fold higher risk of SIDS compared with the general population. Shared genetic and/or environmental factors may contribute to the observed clustering of SIDS. The family history of SIDS should be considered when assessing SIDS risk in clinical settings. A multidisciplinary genetic evaluation of families with SIDS could provide additional evidence.

Integrating new knowledge into practice: An evaluation study on a continuing education for Swedish child health nurses on non-synostotic plagiocephaly

AIM

The aim of this study was to assess what knowledge on non-synostotic plagiocephaly prevention and reversal intervention and control group nurses imparted to parents and parents integrated in infant care.

DESIGN

A group of nurses participated in a continuing education on non-synostotic plagiocephaly in one-to-one or small group sessions at their workplace and received guidelines to follow. An evaluation was conducted with 35 intervention group and 15 control group nurses by asking them two open-ended questions 1 year later; 181 intervention group and 90 control group parents were also asked two open-ended questions and to rate their infant's head shape.

METHODS

Data were collected during the year 2013. Qualitative content analysis and case-by-case analysis were conducted using a process-oriented approach.

RESULTS

Intervention group nurses imparted both regular and newly introduced knowledge on positioning strategies to parents. Intervention group parents who perceived severe cranial asymmetry when infants were 3-4 months old reported implementing regular and new infant positioning recommendations.

Area-based study shows most parents follow advice to reduce risk of sudden infant death syndrome

Aim

Guidance on reducing the risk of sudden infant death syndrome (SIDS) was successfully introduced to a number of countries in the early 1990s. The most important recommendations were supine sleeping for infants and non‐smoking for mothers. This 2012–2014 study examined adherence to the national Swedish SIDS advice.

Methods

We asked 1000 parents with infants registered at child healthcare centres in western Sweden to complete a questionnaire on infant care from birth to 12 months of age.

Results

We analysed 710 responses and found that, in the first three months, 1.3% of the infants were placed in the prone sleeping position and 14.3% were placed on their side. By three to five months, this had risen to 5.6% and 23.6%. In the first three months, 83.1% were breastfed, 84.1% used a pacifier and 44.2% shared their parents' bed, while 5.8% slept in another room. Bed sharing was more likely if infants were breastfed and less likely if they used pacifiers. During pregnancy, 2.8% of the mothers smoked and the mothers who had smoked during pregnancy were less likely to bed share.

Conclusion

Overall adherence to the SIDS advice was good, but both prone and side sleeping practices should be targeted.

Parent-child bed-sharing: The good, the bad, and the burden of evidence

The practice of parent and child sharing a sleeping surface, or 'bed-sharing', is one of the most controversial topics in parenting research. The lay literature has popularized and polarized this debate, offering on one hand claims of dangers, and on the other, of benefits - both physical and psychological - associated with bed-sharing. To address the scientific evidence behind such claims, we systematically reviewed 659 published papers (peer-reviewed, editorial pieces, and commentaries) on the topic of parent-child bed-sharing. Our review offers a narrative walkthrough of the many subdomains of bed-sharing research, including its many correlates (e.g., socioeconomic and cultural factors) and purported risks or outcomes (e.g., sudden infant death syndrome, sleep problems). We found general design limitations and a lack of convincing evidence in the literature, which preclude making strong generalizations. A heat-map based on 98 eligible studies aids the reader to visualize world-wide prevalence in bed-sharing and highlights the need for further research in societies where bed-sharing is the norm. We urge for multiple subfields - anthropology, psychology/psychiatry, and pediatrics - to come together with the aim of understanding infant sleep and how nightly proximity to the parents influences children's social, emotional, and physical development.

Improving Survival and Neurologic Function for Younger Age Groups After Out-of-Hospital Cardiac Arrest in Sweden: A 20-Year Comparison

OBJECTIVE

To describe changes in the epidemiology of out-of-hospital cardiac arrest in Sweden with the emphasis on the younger age groups.

DESIGN

Prospective observational study.

SETTING

Sweden.

PATIENTS

Patients were recruited from the Swedish Registry of Cardiopulmonary Resuscitation from 1990 to 2012. Only non-crew-witnessed cases were included.

INTERVENTION

Cardiopulmonary resuscitation.

MEASUREMENT AND MAIN RESULTS

The endpoint was 30-day survival. Cerebral function among survivors was estimated according to the cerebral performance category scores. In all, 50,879 patients in the survey had an out-of-hospital cardiac arrest, of which 1,321 (2.6%) were 21 years old or younger and 1,543 (3.0%) were 22-35 years old. On the basis of results from 2011 and 2012, we estimated that there are 4.9 cases per 100,000 person-years in the age group 0-21 years. The highest survival was found in the 13- to 21-year age group (12.6%). Among patients 21 years old or younger, the following were associated with an increased chance of survival: increasing age, male gender, witnessed out-of-hospital cardiac arrest, ventricular fibrillation, and a short emergency medical service response time. Among patients 21 years old or younger , there was an increase in survival from 6.2% in 1992-1998 to 14.0% in 2007-2012. Among 30-day survivors, 91% had a cerebral performance category score of 1 or 2 (good cerebral performance or moderate cerebral disability) at hospital discharge.

CONCLUSIONS

In Sweden, among patients 21 years old or younger, five out-of-hospital cardiac arrests per 100,000 person-years occur and survival in this patient group has more than doubled during the past two decades. The majority of survivors have good or relatively good cerebral function.

Bed sharing is more common in sudden infant death syndrome than in explained sudden unexpected deaths in infancy

Aim

Despite its declining incidence, sudden infant death syndrome (SIDS) is still an important cause of death in infancy. This study investigated the environmental circumstances associated with SIDS, by analysing data from all sudden unexpected deaths in infancy (SUDI) in Sweden from 2005 to 2011.

Methods

All Swedish infants forensically autopsied up to the age of 365 days from 2005 to 2011 were included. Medical records were obtained from the hospitals and supplementary data from the Swedish Medical Birth Register.

Results

Of the 261 infants, 136 were defined as SIDS and 125 as explained SUDI. The documentation in the medical records was poor when it came to issues such as bed sharing, sleep position, smoking, breastfeeding and pacifier use. The main findings were a significantly higher prevalence of bed sharing in SIDS than in explained deaths (odds ratio 7.77, 95% confidence interval 2.36–25.57) and that prone sleeping was still overrepresented. Bronchopneumonia, other infections and congenital anomalies were the most common causes of explained SUDI.

Conclusion

Bed sharing and prone sleeping were more common in SIDS than in explained SUDI. Sparse data in medical records were a problem, and the authors are now working with the National Board of Health and Welfare on a project to establish new routines.

Maternal and pregnancy characteristics and risk of infantile hypertrophic pyloric stenosis

BACKGROUND/PURPOSE

The incidence of infantile hypertrophic pyloric stenosis (IHPS) in Sweden decreased dramatically during the 1990s. The aim of the study was to examine IHPS risk factors and the possible change in them as the incidence declined.

METHODS

This is a case-control study including 3608 surgically treated IHPS cases and 17588 matched controls during 1973-2008. Cases were identified in the Swedish National Patient Register and data on possible risk factors were collected from the Swedish Medical Birth Register. The association between study variables and IHPS was analyzed using conditional logistic regression for the whole study period and separately for periods with high and low IHPS incidences.

RESULTS

Prematurity (OR, 2.54; 95% CI, 2.06-3.14), caesarean delivery (OR, 1.67; 95% CI, 1.51-1.86), maternal smoking (OR, 1.82; 95% CI, 1.53-2.16), and young maternal age (< 20yrs) (OR, 1.42; 95% CI, 1.17-1.73) were associated with an increased IHPS risk. Birth order 2 (OR, 0.78; 95% CI, 0.71-0.85) or more was associated with a lower IHPS risk. ORs for smoking increased at low incidence rate.

CONCLUSION

We report caesarean section, prematurity, primiparity, young maternal age, and smoking as significant IHPS risk factors. The impact of smoking was higher during periods with a low incidence.

Sudden twin infant death on the same day: a case report and review of the literature

Sudden infant death syndrome (SIDS) is a major contributor to infant mortality. The cause of death is unknown: suggested possibilities include cardiovascular disease, anaphylactic shock, and suffocation. The occurrence of simultaneous sudden infant death syndrome is uncommon, such cases being extremely rare in forensic pathologic practice. We report two 10-week-old male twins who appeared well at the time of their evening feeding, yet died while sleeping on their backs. Both infants had petechial hemorrhages on the visceral pleura, epicardial surface of the heart, and thymus gland. Microscopic examination revealed pulmonary edema, intra-alveolar hemorrhage, and minor lymphocytic infiltration, again in both infants. In this report, we discuss the risk factors for SIDS, which should be considered individually or in combination as possible causes of death.

Maternal smoking and increased risk of sudden infant death syndrome: a meta-analysis

Maternal smoking is detrimental to the development of fetuses and neonates. This meta-analysis was performed to measure the accumulated association of sudden infant death syndrome (SIDS) risk with both prenatal and postnatal maternal smoking. The odds ratio (OR) corresponding to the 95% confidence interval (CI) was used to assess the associations between maternal smoking and SIDS risk. The statistical heterogeneity among studies was assessed with the Q-test and I(2) statistics. The data for this meta-analysis were available from 35 case-control studies. The prenatal and postnatal maternal smoking was associated with a significantly increased risk of SIDS (OR=2.25, 95% CI=2.03-2.50 for prenatal maternal smoking analysis, and OR=1.97, 95% CI=1.77-2.19 for postnatal maternal smoking analysis, respectively) by random effects model. After stratified analyses, regardless of prenatal or postnatal smoking, heavy cigarette consumption increased the risk of SIDS and significantly elevated SIDS risk was found to be associated with co-sleeping with postnatal smoking mothers. Our results suggested that maternal smoking were associated with elevated SIDS risk, the effects were dose-dependent. In addition, SIDS risk was significantly increased in infants co-sleeping with postnatal smoking mothers.

Early protective and risk factors for allergic rhinitis at age 4½ yr

Allergic heredity plays a major role in the development of allergic rhinitis. In addition the introduction of food may influence the risk of subsequent allergic disease. The aim of this study was to analyse early risk factors and protective factors for allergic rhinitis at preschool age. Data were obtained from a prospective, longitudinal study of a cohort of children born in the region of western Sweden in 2003 and 8,176 families (50% of the birth cohort) were randomly selected. The parents answered questionnaires at 6 and 12 months and at 4½ yr of age. The response rate at 4½ yr was 4,496, i.e. 83% of the 5,398 questionnaires distributed at 4½ yr. At 4½ yr of age, 5.5% reported symptoms of allergic rhinitis during the last year. In the multivariate analysis, independent risk factors for allergic rhinitis were: allergic sensitisation to food allergens at 4½ yr (OR 10.21; 95% confidence interval 4.22-24.73), recurrent wheeze at 4½ yr (3.33; 1.56-7.10), doctor-diagnosed eczema at 4½ yr (2.72; 1.62-4.55), parental rhinitis (2.21; 1.39-3.53), eczema first year (1.97; 1.19-3.26) and male gender (1.82; 1.13-2.94). The risk was reduced with fish introduction before 9 months (0.49; 0.29-0.82). In conclusion, we found that previous and present allergic disease, heredity and male gender increased the risk of allergic rhinitis at 4½ yr of age. The introduction of fish before the age of 9 months reduced the risk.

Chronic Lung Disease of Childhood: Control of Breathing During Wake and Sleep

Control of breathing in infants during wake and sleep is immature at birth and undergoes rapid maturation over the first year of life. Infants with chronic lung disease (CLD) have multiple control of breathing impairments leaving them particularly vulnerable to hypoxic and asphyxic events. These impairments in the control of breathing are thought to contribute significantly to increased morbidity and the increased incidence of sudden infant death in infants with CLD. This review provides an overview of factors integral to the control of breathing during wake and sleep and factors that influence the development of control of breathing with a focus on the impact of CLD.

Postnatal parental smoking: an important risk factor for SIDS

BACKGROUND

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]).

CONCLUSION

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 syndrome during low incidence in Sweden 1997-2005

BACKGROUND

Following the change from prone to supine in preferred sleeping position, the incidence of Sudden Infant Death Syndrome (SIDS) in Sweden fell from 1.1 per 1000 live births in 1992 to 0.41 in 1995. After a further small decline, we have been experiencing a plateau at around 0.25 since 2000.

AIM

To identify the changes that have occurred in the epidemiology of SIDS since the end of the Nordic Epidemiological SIDS Study in 1995.

METHODS

Data from the Medical Birth Register of Sweden, covering the years 1995-2005, were used. Sleeping position is not included in the register.

RESULTS

The incidence of SIDS has remained low in Sweden. Independent risk factors were smoking during early pregnancy, parents not living together, low maternal age, high parity and short gestational age. The odds ratio for smoking has continued to increase and the median age of death has continued to decrease since the previous study. We found no signs of seasonality in the current material.

CONCLUSIONS

Age at death continued to decrease. The high incidence during weekends persisted. Seasonality was not significant. There was no evidence of a changing effect from risk factors in the studied period.

Early introduction of fish decreases the risk of eczema in infants

BACKGROUND

Atopic eczema in infants has increased in western societies. Environmental factors and the introduction of food may affect the risk of eczema.

AIMS

To investigate the prevalence of eczema among infants in western Sweden, describe patterns of food introduction and assess risk factors for eczema at 1 year of age.

METHODS

Data were obtained from a prospective, longitudinal cohort study of infants born in western Sweden in 2003; 8176 families were randomly selected and, 6 months after the infant's birth, were invited to participate and received questionnaires. A second questionnaire was sent out when the infants were 12 months old. Both questionnaires were completed and medical birth register data were obtained for 4921 infants (60.2% of the selected population).

RESULTS

At 1 year of age, 20.9% of the infants had previous or current eczema. Median age at onset was 4 months. In multivariable analysis, familial occurrence of eczema, especially in siblings (OR 1.87; 95% confidence interval (CI) 1.50 to 2.33) or the mother (OR 1.54; 95% CI 1.30 to 1.84), remained an independent risk factor. Introducing fish before 9 months of age (OR 0.76; 95% CI 0.62 to 0.94) and having a bird in the home (OR 0.35; 95% CI 0.17 to 0.75) were beneficial.

CONCLUSIONS

One in five infants suffer from eczema during the first year of life. Familial eczema increased the risk, while early fish introduction and bird keeping decreased it. Breast feeding and time of milk and egg introduction did not affect the risk.

SIDS diagnosis should not be put to bed

The finding that prone sleeping position and smoking are important risk factors for SIDS has considerably reduced the incidence. Although these risk factors can be found in many cases of SIDS, they cannot be regarded as causes of death.

CONCLUSION

The diagnosis of SIDS must be adhered to, and risk factors must not be confused with diagnoses. A structured follow-up of all cases of SIDS can be a cost-effective mean to ensure that parents and researchers are given adequate information.

Neonatal antibiotic treatment is a risk factor for early wheezing

OBJECTIVE

The use of antibiotics in infancy and subsequent changes in the intestinal bacterial flora have been discussed as risk factors for the development of asthma. However, it has been difficult to exclude the possibility that antibiotics have been given in early episodes of wheezing. As a result, there has been a risk of reverse causation. To minimize the risk of reverse causation, we have focused on the effect of antibiotics that are already administered on the neonatal ward.

METHODS

In a cohort study of infants born in western Sweden in 2003, we studied the development of wheezing. The families of the infants were randomly selected and sent a questionnaire at child ages 6 and 12 months. The response rate was 68.5% to the 6-month questionnaire and 68.9% to the 12-month questionnaire.

RESULTS

At 12 months, 20.2% of infants had had 1 or more episodes of wheezing, and 5.3% had had 3 or more episodes. Inhaled corticosteroids had been taken by 4.1% of the infants. Independent risk factors for wheezing disorder treated with inhaled corticosteroids were neonatal antibiotic treatment, male gender, gestational age of <37 weeks, having a mother with asthma, having a sibling with asthma or eczema, and breastfeeding for <5 months.

CONCLUSIONS

Treatment with antibiotics in the neonatal period was an independent risk factor for wheezing that was treated with inhaled corticosteroids at 12 months of age. These results indirectly support the hypothesis that an alteration in the intestinal flora can increase the risk of subsequent wheezing.