Very low birth weight increases risk for sleep-disordered breathing in young adulthood: the Helsinki Study of Very Low Birth Weight Adults

Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease, associated with premature birth, that arises during the infantile period. It is an evolving disease process with an unchanged incidence due to advancements in neonatal care which allow for the survival of premature infants of lower gestational ages and birth weights. Currently, there are few effective interventions to prevent BPD. However, careful attention to BPD phenotypes and comprehensive care provided by an interdisciplinary team have improved care. Interventions early in the disease course hold promise for improving long-term survival and outcomes in adulthood for this high-risk population.

Respiratory polygraphy in children with bronchopulmonary dysplasia: a retrospective study

BACKGROUND

Periodic assessment of the need for oxygen supplementation and/or mechanical ventilation in children with severe bronchopulmonary dysplasia (BPD) is crucial. The aim of the study was to analyze the indications and results of respiratory polygraphies (RP) performed in preterm infants with BPD followed at a tertiary university hospital.

METHODS

All subjects <5-year-old with BPD who had a RP between September and February 2018 were included. The indications and results of RP and consequent medical management were analyzed.

RESULTS

Fourteen infants (9 females, mean gestational age 27.6±3.3 weeks) underwent a RP at mean age of 26.4±19.4 months. Five subjects were evaluated for the need of long-term respiratory support (RS), 3 started continuous positive airway pressure (CPAP), 2 were weaned from RS. Four subjects underwent RP for suspected obstructive sleep apnea (OSA), one started on CPAP. Central apnea syndrome (CSA) was confirmed in 2 subjects and one was started on non-invasive ventilation. RP allowed safe tracheostomy decannulation in 2 subjects. Finally, RP was normal in one subject who had a brief resolved unexplained event.

CONCLUSIONS

RP represents an important tool for the evaluation of children with BPD and leads to important therapeutic decisions.

Polysomnographically Defined Restless Sleep Disorder and Periodic Limb Movements during Sleep in Children Born Prematurely

INTRODUCTION

Children born prematurely (<37 weeks' gestation) are at increased risk of perinatal complications, comorbidities, and iron deficiency. Iron deficiency is associated with restless legs syndrome and periodic limb movement disorder. In this study, we assessed the prevalence of restless sleep disorder (RSD) and elevated periodic limb movements during sleep (PLMS) in children born prematurely who underwent polysomnography.

METHODS

A retrospective chart review of sleep studies was conducted in children aged 1-18 years (median age 4 years) with a history of premature birth. Children with genetic syndrome, airway surgery, or tracheostomy were excluded. Three groups were compared: children with PLMS index >5, children with RSD, and children with neither elevated PLMS index nor RSD.

RESULTS

During the study, 2577 sleep studies were reviewed. Ninety-two studies fit our criteria and were included in the analysis. The median age at birth was 31 weeks, and the interquartile range (IQR) was 27-34 weeks. A total of 32 (34.8%) children were referred for restless sleep and 55 (59.8%) for snoring. After polysomnography, 18% were found to have a PLMS index >5/h, and 14% fit the criteria for restless sleep disorder (RSD). There were no statistically significant differences in PSG parameters among the children with RSD, PLMS, and the remaining group, except for lower obstructive apnea/hypopnea index (Kruskal-Wallis ANOVA 8.621, p = 0.0135) in the RSD group (median 0.7, IQR 0.3-0.9) than in the PLMS (median 1.7, IQR 0.7-3.5) or the non-RSD/non-PLMS (median 2.0, IQR 0.8-4.5) groups.

CONCLUSIONS

There was an elevated frequency of RSD and elevated PLMS in our cohort of children born prematurely. Children born prematurely are at higher risk of iron deficiency which can be a contributor factor to sleep -related movement disorders. These results add new knowledge regarding the prevalence of RSD and PLMS in these children.

High Prevalence of Obstructive Sleep-Disordered Breathing in Pediatric Patients With Turner Syndrome

OBJECTIVE

Girls with Turner syndrome (TS) often have features that have been associated with obstructive sleep-disordered breathing (oSDB). However, little is known about oSDB in TS. Herein, we aimed to characterize oSDB in young patients with TS and identify associated risk factors.

STUDY DESIGN

Retrospective cross-sectional study.

SETTING

Tertiary care pediatric hospital.

METHODS

We reviewed medical records for patients diagnosed with TS seen at our institution between October 1, 2007 and December 31, 2019 with the first outpatient visit before age 6 years. The prevalence of oSDB was compared to the general pediatric population with 1-sample binomial proportion tests. Clinical characteristics were compared between those diagnosed with oSDB and those without oSDB, and risk factors for oSDB were identified.

RESULTS

Of 151 patients with TS, 73 (48%) were diagnosed with oSDB which is 4-fold higher than the general pediatric population (12%, P < 0.0001). In the multivariable model, adenoid, tonsillar, and inferior turbinate hypertrophy, birthweight, failure to thrive, and older age at the last clinic visit were all associated with increased odds for oSDB.

CONCLUSION

Young children with TS have a high prevalence of oSDB and thus should be screened for oSDB. Polysomnography should be performed in those with associated risk factors and symptoms oSDB. Treatment of oSDB is imperative as individuals with TS are already at increased risk of behavioral problems, neurocognitive deficits, and growth impairment that may be worsened with oSDB.

Childhood sleep: assessments, risk factors, and potential mechanisms

BACKGROUND

Sleep problem is a highly prevalent health issue among pediatric populations across the world. In this review, we aimed to identify risk factors contributing to sleep deficiency and poor sleep hygiene in children. Potential biological, psychosocial, and environmental mechanisms as well as research gaps in the literature are also discussed.

DATA SOURCES

A comprehensive search for relevant English language full-text, peer-reviewed publications was performed focusing on pediatric sleep studies from prenatal to childhood and adolescence in a variety of indexes in PubMed, SCOPUS, and Psych Info. Both relevant data based and systematic reviews are included.

RESULTS

This paper summarizes many risk factors for childhood sleep problems, including biological (e.g., genetics, gender, age and puberty, prenatal factors, postnatal factors); nutritional (e.g., macronutrients, micronutrients, omega-3 fatty acids, obesity); environmental (e.g., heavy metals, noise, light, air pollution); interpersonal (e.g., family, exposure to violence, screen media use, physical injury); and community/socioeconomic variables (e.g., racial/ethnicity and cultural factors, neighborhood conditions and socioeconomic status, school factors, public health disasters/emergencies), to better understand the development of sleep problems in children.

CONCLUSIONS

Poor childhood sleep is a multifactorial issue affected by a wide range of prenatal and early-life biological, environmental, and psychosocial risk factors and contributors. A better understanding of these risk factors and their mechanisms is an important first step to develop future research and prevention programs focusing on pediatric sleep problems.

Heart rate surge at respiratory event termination in preterm and term born children with sleep disordered breathing

BACKGROUND

Repetitive surges in heart rate (HR) at respiratory event termination underpin the altered autonomic HR control associated with sleep disordered breathing (SDB). As children born preterm are at greater risk of adverse cardiovascular outcomes, we aimed to determine whether the HR response to obstructive respiratory events was elevated compared to term-born children.

METHODS

Fifty children (3-12 years) born preterm, were matched for SDB severity, age and gender with term born children. Multilevel modelling determined the effect of preterm birth and arousal on HR changes between a 10s baseline to the latter half of respiratory events and 15s post event during NREM and REM.

RESULTS

1203 events were analysed (NREM: term 380; preterm 383; REM: term 207; preterm 233). During NREM fewer events terminated in arousal in the preterm compared with term group (preterm 68%; term 84%; χ² = 27.2, p < 0.001). There were no differences in REM. During NREM, HR was lower in the preterm group at all event phases, with and without associated arousals (P < 0.01 for all). % change in HR from baseline to post event was higher in the preterm compared with term group (preterm: median 23% IQR (12%,34%); term: 18% (10%,29%); p < 0.01) and late event to post event (preterm: 30% (21%, 32%); term 28% (20%,39%); p < 0.01) in events associated with arousals.

CONCLUSION

The greater magnitude of surges in HR following respiratory events terminating with arousal in preterm born children, although small, occur repeatedly throughout the night and may contribute to adverse cardiovascular outcomes, although further studies are required.

Comparison of polysomnographic characteristics between low birthweight and normal birthweight children in the Northern Territory of Australia: A case-control study

OBJECTIVES

To describe the sleep architecture of pediatric patients according to whether they were born low birthweight (birthweight <2500 g, LBW) or normal birthweight (birthweight >2500 g).

DESIGN

Case control study.

SETTING

Pediatric sleep laboratory in the Northern Territory of Australia during a 5-year study period (2015- 2020).

PARTICIPANTS

Pediatric patients (aged <18 years) referred to the specialist sleep service for assessment of clinically suspected sleep disorders.

MEASUREMENTS

Sleep onset latency, rapid eye movement (REM) sleep latency, wake time after sleep onset, total sleep time, sleep efficiency, non-rapid eye movement stages N1/N2/N3, and REM sleep duration, total/spontaneous/respiratory/limb related arousal indexes, total/non-rapid eye movement/REM obstructive apnea-hypopnea index and oxygen saturation.

RESULTS

One hundred and seventy-two pediatric patients had birthweight data available of whom 19 were LBW. LBW patients showed significantly greater sleep disruption and higher prevalence of poor sleepers (<80% efficiency). In multivariate regression models, increasing birthweight was associated with significantly greater sleep efficiency and total sleep time. After accounting for gestational age LBW was associated with increased odds of obstructive sleep apnea.

CONCLUSIONS

Among pediatric patients LBW is associated with increased sleep disruption and reduced sleep efficiency. This is attenuated by gestational age, though both gestational age and LBW significantly influence odds of obstructive sleep apnea. This sleep health deficit may contribute to development of chronic disease in this vulnerable population, and should be monitored to provide avenues for early intervention.

Frequent hypoxemia found in infants with bronchopulmonary dysplasia after weaning home oxygen

OBJECTIVE

Parental reports and brief clinical examinations are the primary information used to assist clinicians in weaning home supplemental oxygen in infants with bronchopulmonary dysplasia (BPD). Recorded nocturnal oximetry provides an objective assessment of hypoxemia; however, it is unknown if it identifies clinically undetected hypoxemia in the home setting. Our objective was to determine if nocturnal oximetry can identify unreported hypoxemia in infants with BPD who appear ready to wean from supplemental oxygen.

STUDY DESIGN

We conducted a retrospective chart review of infants born <32 weeks gestation with BPD who were discharged to home receiving supplemental oxygen and completed recorded nocturnal oximetry in room air during an 18-month period. Abnormal oximetry was defined as >5 min with SpO₂  < 90% and/or an oxyhemoglobin desaturation index (ODI4) >5. Comparative analysis of patients with normal and abnormal overnight oximetry was performed using Fisher Exact and Wilcoxon signed-rank test.

RESULTS

Thirty-five former premature infants completed nocturnal oximetry at 5.8 (3.4-8.3) months corrected age. Nocturnal oximetry was abnormal as defined in 67% of the cohort (n = 21). Five percent of patients were hypoxemic, 52% had frequent desaturation events, and 43% had both. No significant differences existed in neonatal characteristics between patients with normal and abnormal studies.

CONCLUSIONS

Nocturnal oximetry was abnormal in the majority of infants with BPD who were otherwise clinically ready to wean from oxygen support, suggesting that recorded home oximetry could be a feasible and useful tool to evaluate for otherwise clinically unapparent nocturnal hypoxemia in patients with BPD.

Socioeconomic inequality in the prevalence of low birth weight and its associated determinants in Bangladesh

BACKGROUND AND OBJECTIVE

Low birth weight (LBW) is a major risk factor of child mortality and morbidity during infancy (0-3 years) and early childhood (3-8 years) in low and lower-middle-income countries, including Bangladesh. LBW is a vital public health concern in Bangladesh. The objective of the research was to investigate the socioeconomic inequality in the prevalence of LBW among singleton births and identify the significantly associated determinants of singleton LBW in Bangladesh.

MATERIALS AND METHODS

The data utilized in this research was derived from the latest nationally representative Bangladesh Demographic and Health Survey, 2017-18, and included a total of 2327 respondents. The concentration index (C-index) and concentration curve were used to investigate the socioeconomic inequality in LBW among the singleton newborn babies. Additionally, an adjusted binary logistic regression model was utilized for calculating adjusted odds ratio and p-value (<0.05) to identify the significant determinants of LBW.

RESULTS

The overall prevalence of LBW among singleton births in Bangladesh was 14.27%. We observed that LBW rates were inequitably distributed across the socioeconomic groups (C-index: -0.096, 95% confidence interval: [-0.175, -0.016], P = 0.029), with a higher concentration of LBW infants among mothers living in the lowest wealth quintile (poorest). Regression analysis revealed that maternal age, region, maternal education level, wealth index, height, age at 1st birth, and the child's aliveness (alive or died) at the time of the survey were significantly associated determinants of LBW in Bangladesh.

CONCLUSION

In this study, socioeconomic disparity in the prevalence of singleton LBW was evident in Bangladesh. Incidence of LBW might be reduced by improving the socioeconomic status of poor families, paying special attention to mothers who have no education and live in low-income households in the eastern divisions (e.g., Sylhet, Chittagong). Governments, agencies, and non-governmental organizations should address the multifaceted issues and implement preventive programs and policies in Bangladesh to reduce LBW.

Disturbed sleep in children born extremely preterm is associated with behavioural and emotional symptoms

AIM

To determine whether children born extremely preterm are at increased risk for sleep disturbances and to explore relationships between extremely preterm birth, sleep and attention-deficit/hyperactivity disorder (ADHD) symptoms and emotional symptoms.

METHOD

EPICure2 cohort study. Parents of 165 children born ≤26 weeks' gestation (53% male) and 121 children born at term (43% male) completed the Children's Sleep Habits Questionnaire, sleep disordered breathing subscale of the Pediatric Sleep Questionnaire, the emotional problems scale of the Strengths and Difficulties Questionnaire and the ADHD Rating Scale-5 at 11 years of age.

RESULTS

Extremely preterm children had greater habitual snoring (adjusted odds ratio 6.8; 95% confidence interval 2.3, 20.3), less frequently fell asleep within 20 minutes (Cohen's d 0.33), higher night wakings (d 0.44) and daytime sleepiness scores (d 0.40) than term-born children; there was no between-group difference in sleep duration scores. Among children without severe disability, night wakings scores partially mediated the relationship between preterm birth and inattention (additional 5% of variance explained), hyperactivity/impulsivity (13%) and emotional problems (9%). Snoring partially mediated the relationship between preterm birth, hyperactivity/impulsivity and inattention (additional 1-5% of variance).

CONCLUSION

Children born extremely preterm are at increased risk of disturbed sleep compared to term-born children. As night wakings partially mediated the relationship between preterm birth and ADHD symptoms and emotional problems, reducing sleep disturbance may improve sleep and reduce attention and emotional problems in this population.

Perinatal antecedents of sleep disturbances in schoolchildren

STUDY OBJECTIVES

Prematurity has been associated with an increased risk for sleep apnea. However, sleep disturbances in children born preterm have not been extensively investigated. Considering that determinants of sleep may originate early in life, the potential impact of prematurity on sleep disturbances later in life could be important. To establish the role of prematurity on sleep disturbances in a cohort of schoolchildren that were born preterm and compare them with healthy controls.

METHODS

A cohort of 147 schoolchildren, 45 born at term (≥37 weeks) and 102 very preterm (<32 weeks), was recruited and evaluated at school age (5-9 years). The Pediatric Sleep Questionnaire (PSQ) and the Sleep Disturbance Scale for Children (SDSC) were used to assess sleep disturbances in different domains.

RESULTS

PSQ score was significantly higher in former preterm children (0.26 ± 0.18 vs. 0.18 ± 0.14 in controls; p = 0.004), and SDSC total score was also significantly different among groups (21.7 ± 11.6 vs. 14.1 ± 12.6; p < 0.001). Regression models showed significant mean differences in PSQ score, total SDSC score, and two SDSC subscale scores (i.e. sleep-wake transition disorders, sleep-breathing disorders, and sleep hyperhidrosis) even after adjustment for confounders. Maternal age and type of delivery were not significantly associated with total PSQ scores.

CONCLUSIONS

Sleep disturbances may originate early in life since children born preterm exhibit an increased risk for developing long-term sleep problems. These findings may have important implications for management of preterm children and for implementation of early interventions focused on optimizing sleep habits.

Hypoxia-inducible factors and obstructive sleep apnea

Intermittent hypoxia (IH) is a hallmark manifestation of obstructive sleep apnea (OSA), a widespread disorder of breathing. This Review focuses on the role of hypoxia-inducible factors (HIFs) in hypertension, type 2 diabetes (T2D), and cognitive decline in experimental models of IH patterned after O2 profiles seen in OSA. IH increases HIF-1α and decreases HIF-2α protein levels. Dysregulated HIFs increase reactive oxygen species (ROS) through HIF-1-dependent activation of pro-oxidant enzyme genes in addition to reduced transcription of antioxidant genes by HIF-2. ROS in turn activate chemoreflex and suppress baroreflex, thereby stimulating the sympathetic nervous system and causing hypertension. We also discuss how increased ROS generation by HIF-1 contributes to IH-induced insulin resistance and T2D as well as disrupted NMDA receptor signaling in the hippocampus, resulting in cognitive decline.

Nocturnal events in children: When and how to evaluate

Nocturnal events of wide variety and concern are frequently reported by patients and their caregivers. To evaluate suspected abnormal events, primary care physicians must first be familiar with normal behaviors, movements and breathing patterns. Abnormal nocturnal events can then be categorized as nocturnal seizure, parasomnia, sleep-related movement disorder or sleep-related breathing disorder. Diagnoses in the above categories can be made clinically; however, it is important to know when to refer for additional evaluation. Comprehensive literature review was undertaken of nocturnal and sleep-related disorders. This guide reviews nocturnal seizures, normal and abnormal nonepileptic movements and behaviors, discusses broad indications for referral for electroencephalography (EEG) or polysomnography (PSG), and guides counseling and management for patients and their families, ultimately aiding in interpretation of both findings and prognosis. Epilepsy syndromes can result in seizures during sleep or adjacent periods of wakefulness. Parasomnias and sleep-related movement disorders tend to also occur in childhood and may be distinguished clinically. Referral to additional specialists for specific studies including EEG or PSG can be necessary, while other times a knowledgeable and vigilant clinician can contribute to a prompt diagnosis based on clinical features. Nocturnal events often can be managed with parental reassurance and watchful waiting, but treatment or evaluation may be needed. Sleep-related breathing disorders are important to recognize as they present very differently in children than in adults and early intervention can be life-saving. This review should allow both primary and subspecialty non-neurologic pediatric and adolescent health care providers to better utilize EEG and PSG as part of a larger comprehensive clinical approach, distinguishing and managing both epileptic and nonepileptic nocturnal disorders of concern while fostering communication across providers to facilitate and coordinate better holistic long-term care of pediatric and adolescent patients.

An overview of adult health outcomes after preterm birth

Preterm birth (gestational age < 37 completed weeks) has increased in prevalence in most countries in the past 20 years and now affects nearly 11% of all births worldwide. Because of treatment advances introduced in the 1970s-1980s, >95% of preterm infants who receive modern neonatal and pediatric care now survive into adulthood. The earliest birth cohorts to benefit from those advances are now in their 4th and 5th decades of life. A growing number of large cohort studies have investigated the long-term health sequelae in adulthood. Evidence has consistently shown that adult survivors of preterm birth have increased risks of chronic disorders involving various organ systems, including cardiovascular, endocrine/metabolic, respiratory, renal, neurodevelopmental, and psychiatric disorders, which either persist from childhood into adulthood or sometimes first manifest in adulthood. These disorders also lead to moderately (30% to 50%) increased mortality risks during early to mid-adulthood among persons born preterm compared with full-term, and even higher risks among those born at the earliest gestational ages. However, the majority of persons born preterm have low absolute risks of these outcomes and good self-reported quality of life in adulthood. Priorities for future research include the assessment of long-term health sequelae of preterm birth in racially and economically diverse populations, additional follow-up of existing cohorts into older adulthood, elucidation of outcomes by preterm birth subtype (e.g., different underlying causes) to improve risk stratification, and identification of protective factors that will support the long-term health trajectory and well-being of preterm-born adults.

Preterm birth and risk of sleep-disordered breathing from childhood into mid-adulthood

BACKGROUND

Preterm birth (gestational age <37 weeks) has previously been associated with cardiometabolic and neuropsychiatric disorders into adulthood, but has seldom been examined in relation to sleep disorders. We conducted the first population-based study of preterm birth in relation to sleep-disordered breathing (SDB) from childhood into mid-adulthood.

METHODS

A national cohort study was conducted of all 4 186 615 singleton live births in Sweden during 1973-2014, who were followed for SDB ascertained from nationwide inpatient and outpatient diagnoses through 2015 (maximum age 43 years). Cox regression was used to examine gestational age at birth in relation to SDB while adjusting for other perinatal and maternal factors, and co-sibling analyses assessed for potential confounding by unmeasured shared familial factors.

RESULTS

There were 171 100 (4.1%) persons diagnosed with SDB in 86.0 million person-years of follow-up. Preterm birth was associated with increased risk of SDB from childhood into mid-adulthood, relative to full-term birth (39-41 weeks) [adjusted hazard ratio (aHR), ages 0-43 years: 1.43; 95% confidence interval (CI), 1.40, 1.46; P <0.001; ages 30-43 years: 1.40; 95% CI, 1.34, 1.47; P <0.001]. Persons born extremely preterm (<28 weeks) had more than 2-fold risks (aHR, ages 0-43 years: 2.63; 95% CI, 2.41, 2.87; P <0.001; ages 30-43 years: 2.22; 95% CI, 1.64, 3.01; P <0.001). These associations affected both males and females, but accounted for more SDB cases among males (additive interaction, P = 0.003). Co-sibling analyses suggested that these findings were only partly due to shared genetic or environmental factors in families.

CONCLUSIONS

Preterm-born children and adults need long-term follow-up for anticipatory screening and potential treatment of SDB.

Preterm birth and mortality in adulthood: a systematic review

Preterm birth (gestational age < 37 weeks) has a worldwide prevalence of nearly 11%, and >95% of preterm infants who receive modern neonatal and pediatric care now survive into adulthood. However, improved early survival has been accompanied by long-term increased risks of various chronic disorders, prompting investigations to determine whether preterm birth leads to higher mortality risks in adulthood. A systematic review identified eight studies with a total of 6,594,424 participants that assessed gestational age at birth in relation to all-cause or cause-specific mortality at any ages ≥18 years. All six studies that included persons born in 1967 or later reported positive associations between preterm birth and all-cause mortality in adulthood (attained ages, 18-45 years). Most adjusted relative risks ranged from 1.2 to 1.6 for preterm birth, 1.1 to 1.2 for early term birth (37-38 weeks), and 1.9 to 4.0 for extremely preterm birth (22-27 weeks), compared with full-term birth (variably defined but including 39-41 weeks). These findings appeared independent of sociodemographic, perinatal, and maternal factors (all studies), and unmeasured shared familial factors in co-sibling analyses (assessed in four studies). Four of these studies also explored cause-specific mortality and reported associations with multiple causes, including respiratory, cardiovascular, endocrine, and neurological. Two smaller studies based on an earlier cohort born in 1915-1929 found no clear association with all-cause mortality but positive associations with selected cause-specific mortality. The overall evidence indicates that premature birth during the past 50 years is associated with modestly increased mortality in early to mid-adulthood.

Sleep disordered breathing (SDB) in neonates and implications for its long-term impact

Sleep-disordered breathing (SDB) is a significant cause of morbidity in neonates and young infants. SDB occurs more commonly in preterm infants and in neonates with underlying syndromes. Recent evidence shows that infants with obstructive sleep apnoea (OSA) or SDB have greater health care resource utilization, including longer hospital stay. Management of SDB includes non-invasive ventilation or surgical interventions tailored to the patient. Screening high risk newborns should allow for early diagnosis and timely therapeutic intervention for this population. However, the thresholds for diagnosing SDB and for guiding and implementing treatment in neonates remain unclear. A collective effort is required to standardize the practice worldwide. This article will discuss neonatal sleep physiology and characteristics of neonatal sleep, with an emphasis on the epidemiology and diagnosis of SDB in neonates and its implications for long term outcomes.

Sleep macro-architecture and micro-architecture in children born preterm with sleep disordered breathing

BACKGROUND

Both preterm birth and sleep disordered breathing (SDB) affect sleep in children. We compared the effects of SDB on sleep macro-architecture and micro-architecture in children born preterm (N = 50) and children born at term (N = 50). We hypothesized that sleep would be more disrupted in children born preterm.

METHODS

Polysomnographic studies matched for age (3-12 years) and SDB severity were analyzed. Sleep macro-architecture was assessed using standard criteria and micro-architecture was evaluated using spectral analysis of the electroencephalogram and slow wave activity (SWA) calculated for each sleep stage across the night.

RESULTS

Ex-preterm children (gestational age 29.3 ± 3.6 weeks, mean ± standard error of the mean) were not different from controls for demographic or respiratory parameters or sleep macro-architecture. Theta power in N2 tended to be higher for F4 (p < 0.05) and C4 (p < 0.07). In the second non-rapid eye movement period, SWA was significantly higher in the preterm group compared to the term group for both F4 and C4 (p < 0.05 for both).

CONCLUSIONS

Sleep micro-architecture in children born preterm showed increased theta power and SWA. These differences provide evidence of increased sleep debt and reduced dissipation of sleep debt across the night. Further studies are required to identify if these findings are related to impaired neurocognition and behavior.

Preterm prelabor rupture of membranes prior to early preterm delivery elevates the risk of later respiratory-related hospitalizations in the offspring

OBJECTIVE

Preterm prelabor rupture of membranes (PPROM) precedes 30%-40% of all preterm births. Early preterm delivery (<34 gestation weeks) is a well-established risk factor for short- and long-term respiratory morbidity in the offspring. We aimed to ascertain whether the presence of PPROM, before early preterm delivery, independently impacts long-term respiratory hospitalizations in the offspring.

STUDY DESIGN

A population-based retrospective cohort analysis was performed including all singleton early preterm deliveries. Exposure was defined as the presence of PPROM. Hospitalizations of the offspring up to the age of 18 years involving respiratory-related morbidity were evaluated. A Kaplan-Meier survival curve and multivariable Cox regression model were used to assess the association.

RESULTS

During the study period, 3309 early preterm deliveries met the inclusion criteria. In 22.4% of cases (n = 742), PPROM was documented. Rates of respiratory-related hospitalizations of the offspring up to the age of 18 years were significantly higher in the exposed group (12.5% vs 9.4% in the unexposed group, P = .023). The survival curve demonstrated significantly higher cumulative incidence of respiratory hospitalizations in the exposed group (logrank P = .018). In the Cox regression model controlled for gestational age, and other clinically relevant confounders - PPROM before early preterm deliveries was independently associated with an increased risk for long-term childhood respiratory-related hospitalizations in the offspring (adjusted hazard ratio 1.40, 95% confidence interval, 1.05-1.87, P = .021).

CONCLUSION

Fetal exposure to PPROM before early preterm delivery was associated with an increased risk for long-term respiratory hospitalizations in the offspring.

Respiratory Phenotypes for Preterm Infants, Children, and Adults: Bronchopulmonary Dysplasia and More

Ongoing advancements in neonatal care since the late 1980s have led to increased numbers of premature infants surviving well beyond the neonatal period. As a result of increased survival, many individuals born preterm manifest chronic respiratory symptoms throughout infancy, childhood, and adult life. The archetypical respiratory disease of prematurity, bronchopulmonary dysplasia, is the second most common chronic pediatric respiratory disease after asthma. However, there are several commonly held misconceptions. These misconceptions include that bronchopulmonary dysplasia is rare, that bronchopulmonary dysplasia resolves within the first few years of life, and that bronchopulmonary dysplasia does not impact respiratory health in adult life. This focused review describes a spectrum of respiratory conditions that individuals born prematurely may experience throughout their lifespan. Specifically, this review provides quantitative estimates of the number of individuals with alveolar, airway, and vascular phenotypes associated with bronchopulmonary dysplasia, as well as non-bronchopulmonary dysplasia respiratory phenotypes such as airway malacia, obstructive sleep apnea, and control of breathing issues. Furthermore, this review illustrates what is known about the potential for progression and/or lack of resolution of these respiratory phenotypes in childhood and adult life. Recognizing the spectrum of respiratory phenotypes associated with individuals born preterm and providing comprehensive and personalized care to these individuals may help to modulate adverse respiratory outcomes in later life.

Fertility treatments and the risk of pediatric obstructive sleep apnea in the offspring-Results from a population-based cohort study

OBJECTIVE

While the impact of fertility treatments on the perinatal outcome is well established, the long-term effects on offspring are yet to be determined. The current study aimed to investigate the risk of long-term obstructive sleep apnea (OSA) among children born following in vitro fertilization (IVF) and ovulation induction (OI) as compared with spontaneously conceived pregnancies.

STUDY DESIGN

A retrospective population-based cohort study was performed. Exposure was defined as delivery following pregnancies conceived by IVF or OI. Incidence of OSA related hospitalizations of the offspring, up to the age of 18 years, was evaluated. A Kaplan-Meier survival curve and multivariable Cox regression models were used to assess the association.

RESULTS

During the study period, 242 187 singleton deliveries met the inclusion criteria; 1.1% were conceived following IVF (n = 2603), and 0.7% following OI (n = 1721). Offspring hospitalization rates, involving OSA (n = 1607), were higher among children conceived following IVF and OI pregnancies as compared with the rate in children conceived spontaneously (1.4% vs 1.2% vs 0.7%, respectively; P < .001). The Kaplan-Meier survival curve demonstrated a significantly higher cumulative incidence of OSA related hospitalizations following IVF and OI (log-rank P < .001). Using multiple Cox regression models, controlled for gestational age, maternal age, maternal smoking, maternal obesity, birthweight, offspring gender and obesity, IVF as well as OI exhibited a significant and independent association with pediatric OSA in all models with adjusted hazard ratios of 2.25, (95% confidence interval [CI] = 1.6-3.1) and 1.63 (95% CI = 1.1-2.5), respectively.

CONCLUSION

Both IVF and OI treatments appear to be independently associated with OSA in the offspring.

Prenatal, Perinatal, and Early Childhood Factors Associated with Childhood Obstructive Sleep Apnea

OBJECTIVES

To investigate prenatal, perinatal, and early childhood factors, including cord and early childhood plasma leptin, on a clinical diagnosis of obstructive sleep apnea (OSA) among children in the Boston Birth Cohort.

STUDY DESIGN

We conducted a secondary analysis of 2867 mother-child pairs from the Boston Birth Cohort who were enrolled between 1998 and 2014 at Boston Medical Center and followed from birth to age 16 years. Child's OSA was defined based on clinical diagnoses documented in the medical record. Plasma leptin was measured in cord and early childhood blood samples. Logistic regression was used to examine individual and combined effects of early life factors on the risk of OSA, adjusting for potential confounders.

RESULTS

The mean age of the study children was 6.39 years (SD = 3.77); 49.3% were girls, and 209 (7.3%) had ever been diagnosed with OSA. Four significant risk factors for OSA were identified: maternal obesity/diabetes during pregnancy (OR, 1.63; 95% CI, 1.21-2.21; P = .001), preterm/low birth weight (OR, 1.74; 95% CI, 1.30-2.32; P < .001), early childhood obesity (OR, 1.89; 95% CI, 1.37-2.62; P < .001), and high leptin levels in early childhood (OR, 1.94; 95% CI, 1.22-3.09; P = .005). The presence of all these 4 risk factors significantly amplified the odds of OSA by about 10 times (OR, 9.95; 95% CI, 3.42-28.93; P < .001) compared with those lacking these factors.

CONCLUSIONS

Our findings, if further confirmed, provide new insight into the early life risk factors of pediatric OSA and underscore the need for early screening and prevention of OSA among children with those risk factors.

Parental reports showed that snoring in infants at three and eight months associated with snoring parents and smoking mothers

AIM

This prospective study examined the prevalence of snoring during infancy and the prenatal and postnatal risk factors for this condition.

METHODS

The study population comprised 1388 infants from the CHILD-SLEEP birth cohort, who were recruited in the Pirkanmaa Hospital District, Finland, between 2011 and 2013. Sleep and background factor questionnaires were filled out prenatally by parents and when the infant was three and eight months old.

RESULTS

The prevalence of habitual snoring was 3.2% at the age of three months and 3.0% at eight months, and snoring infants had more sleeping difficulties at those ages, with odds ratios (ORs) of 3.11 and 4.63, respectively. At three months, snoring infants slept for a shorter length of time (p = 0.001) and their sleep was more restless (p = 0.004). In ordinal logistic regression models, parental snoring (adjusted OR = 1.65 and 2.60) and maternal smoking (adjusted OR = 2.21 and 2.17) were significantly associated with infant snoring at three and eight months, while formula feeding and dummy use (adjusted OR = 1.48 and 1.56) were only associated with infant snoring at three months.

CONCLUSION

Parental snoring and maternal smoking increased the risk of snoring. Infants who snored also seemed to suffer more from other sleep difficulties.

Cardiovascular Autonomic Control Is Altered in Children Born Preterm with Sleep Disordered Breathing

BACKGROUND

To assess if the effects of sleep disordered breathing (SDB) on heart rate (HR) and HR variability, as a measure of autonomic control, were more severe in a group of children born preterm compared with a group of children born at term referred to our sleep laboratory for assessment of SDB.

STUDY DESIGN

Children (3-12 years of age) referred for polysomnographic assessment of SDB were recruited; 50 born preterm (<37 weeks of gestation) and 50 at term, matched for age and SDB severity. The mean HR and HR variability using power spectral analysis were calculated for each child for wake and sleep, and stages N1, N2, N3, and rapid eye movement sleep.

RESULTS

Ex-preterm children were born between 23 and 35 weeks of gestational age (29.3 ± 3.6; mean ± SEM). There were no differences in the demographic, sleep, or respiratory characteristics between the groups. High-frequency power (reflecting parasympathetic activity) was greater in the ex-preterm children in both N2 and N3 (P < .05 for both) and total power was greater in N3 (P < .05). When the children were divided by SDB severity, these effects were most marked in those preterm born children with moderate to severe disease.

CONCLUSIONS

Preterm born children matched for age and SDB severity with children born at term showed no differences in sleep characteristics; however, they did exhibit increased parasympathetic tone during non-rapid eye movement sleep.

Child sleep problems and adult mental health in those born at term or extremely low birth weight

OBJECTIVES

To examine associations between parent-reported child sleep walking or talking, nightmares, and trouble sleeping at age eight and psychiatric problems in adulthood (age 30-35) in extremely low birth weight (ELBW; <1000 g) survivors and matched normal birth weight (NBW; >2500 g) control participants.

METHODS

At age eight, parents of ELBW survivors and NBW control participants completed sleep items on the Child Behavior Checklist assessing the presence of sleep walking/talking, nightmares, or trouble sleeping. At age 30-35, 98 ELBW and 94 NBW individuals completed the Mini International Neuropsychiatric Interview (MINI), Beck Anxiety Inventory (BAI), and Beck Depression Inventory (BDI). Analyses were conducted in each birth weight group independently.

RESULTS

In NBW participants, sleep walking/talking in childhood predicted higher BAI and BDI scores, as well as more than three times the odds of having a mood or anxiety disorder (OR = 3.48; 95% CI, 1.26-9.60) at age 30-35. Sex and childhood sleep problem interactions revealed that females who manifested sleep walking/talking as children had higher BAI scores than males. Nightmares in children born at NBW predicted higher BAI scores. These associations persisted despite adjustment for child mental health, sex, socioeconomic status, sexual or physical abuse, and family functioning. Trouble sleeping in childhood did not predict adult mental health problems. Childhood sleep problems did not predict psychopathology in ELBW adults.

CONCLUSIONS

Children born at NBW who manifest sleep walking or talking appear to be at increased risk for developing mood or anxiety disorders in adulthood. No associations between child sleep and adult mental illness were noted in those with ELBW surviviors. Childhood sleep walking/talking may be a unique risk factor for mental health problems later in life.

Prenatal and early life origins of adolescence sleep problems: evidence from a birth cohort

PURPOSE

This study aims to identify the prenatal and early life predictors of adolescence sleep problems.

METHODS

Sleep data (n = 5081) from the 14-year (13.92 ± 0.34 years) follow-up of a birth cohort were analyzed to explore the predictors of adolescence trouble sleeping, nightmares, snoring and sleep talking/walking. Data from the antenatal period till adolescence were explored for identifying predictors of adolescence sleep problems. Modified Poisson regression with a robust error variance was used to identify significant predictors.

RESULTS

Our results suggest that about a quarter of adolescents in our study sample had sleep maintenance problems (nightmares: 27.88%, snoring: 23.20%, sleepwalking/talking 27.72%). The prevalence rate of sleep initiation problems was even higher (trouble sleeping: 40.61%). Our results suggest that antenatal and early-life factors, e.g. maternal smoking, anxiety, sleep problems in childhood, attention deficit hyperactivity disorder (ADHD) symptoms, and poor health are significant predictors of adolescence sleep problems.

CONCLUSIONS

This study demonstrates the predictive role of prenatal and early life risk factors in adolescence sleep problems. It seems that exposure to prenatal and early life risk factors increase the vulnerability for sleep problems later in life, which is further supported by poor health and lifestyle choices in adolescence. Therefore, close observation and mitigation of factors associated with early life risk factors could be a potential strategy for preventing sleep problems later in life.

Cardioventilatory Control in Preterm-born Children and the Risk of Obstructive Sleep Apnea

RATIONALE

The contribution of ventilatory control to the pathogenesis of obstructive sleep apnea (OSA) in preterm-born children is unknown.

OBJECTIVES

To characterize phenotypes of ventilatory control that are associated with the presence of OSA in preterm-born children during early childhood.

METHODS

Preterm- and term-born children without comorbid conditions were enrolled. They were categorized into an OSA group and a non-OSA group on the basis of polysomnography.

MEASUREMENTS AND MAIN RESULTS

Loop gain, controller gain, and plant gain, reflecting ventilatory instability, chemoreceptor sensitivity, and blood gas response to a change in ventilation, respectively, were estimated from spontaneous sighs identified during polysomnography. Cardiorespiratory coupling, a measure of brainstem maturation, was estimated by measuring the interval between inspiration and the preceding electrocardiogram R-wave. Cluster analysis was performed to develop phenotypes based on controller gain, plant gain, cardiorespiratory coupling, and gestational age. The study included 92 children, 63 of whom were born preterm (41% OSA) and 29 of whom were born at term (48% OSA). Three phenotypes of ventilatory control were derived with risks for OSA being 8%, 47%, and 77% in clusters 1, 2, and 3, respectively. There was a stepwise decrease in controller gain and an increase in plant gain from clusters 1 to 3. Children in cluster 1 had significantly higher cardiorespiratory coupling and gestational age than clusters 2 and 3. No difference in loop gain was found between clusters.

CONCLUSIONS

The risk for OSA could be stratified according to controller gain, plant gain, cardiorespiratory coupling, and gestational age. These findings could guide personalized care for children at risk for OSA.

Prenatal and Neonatal Factors Predicting Sleep Problems in Children Born Extremely Preterm or With Extremely Low Birthweight

Objective: Prematurely born children have been reported to have more sleep problems throughout childhood than children born at term. The aim of this study was to explore if prenatal or neonatal factors can predict sleep problems at age 11 years in children born extremely preterm (EPT). Method: A prospective observational study of all infants who were born EPT in Norway in 1999 and 2000. Prenatal and neonatal data were collected by all Norwegian obstetric and pediatric departments. Parental questionnaire mapped sleep problems and sleep habits at the age of 11 years. Results: Of the 372 eligible children, 221 participated. Of those, 28.1% snored, 27.5% had difficulty falling asleep or frequent awakenings and 17.2% suffered from daytime sleepiness. The mean sleep duration was 9.4 h (range 4.3-11.0 h). Smoking in pregnancy predicted snoring (odds ratio 4.3). Neonatal cerebral hemorrhage and being born small for gestational age predicted difficulty falling asleep or frequent awakenings (odds ratio 2.2 and 2.3). Other morbidities during pregnancy or the newborn period, gestational age or the burden of treatment in the neonatal intensive care unit did not predict sleep problems. None of the studied prenatal or neonatal factors predicted daytime sleepiness or sleep duration <9 h. Conclusion: Of numerous prenatal and neonatal factors, only smoking during pregnancy, being born small for gestational age and cerebral hemorrhage predicted sleep problems at 11 years of age among these children born EPT.

Carotid body chemoreflex: a driver of autonomic abnormalities in sleep apnoea

What is the topic of this review? This article presents emerging evidence for heightened carotid body chemoreflex activity as a major driver of sympathetic activation and hypertension in sleep apnoea patients. What advances does it heighlight? This article discusses the recent advances on cellular, molecular and epigenetic mechanisms underlying the exaggerated chemoreflex in experimental models of sleep apnoea. The carotid bodies are the principal peripheral chemoreceptors for detecting changes in arterial blood oxygen concentration, and the resulting chemoreflex is a potent regulator of the sympathetic tone, blood pressure and breathing. Sleep apnoea is a disease of the respiratory system that affects several million adult humans. Apnoeas occur during sleep, often as a result of obstruction of the upper airway (obstructive sleep apnoea) or because of defective respiratory rhythm generation by the CNS (central sleep apnoea). Patients with sleep apnoea exhibit several co-morbidities, with the most notable among them being heightened sympathetic nerve activity and hypertension. Emerging evidence suggests that intermittent hypoxia resulting from periodic apnoea stimulates the carotid body, and the ensuing chemoreflex mediates the increased sympathetic tone and hypertension in sleep apnoea patients. Rodent models of intermittent hypoxia that simulate the O2 saturation profiles encountered during sleep apnoea have provided important insights into the cellular and molecular mechanisms underlying the heightened carotid body chemoreflex. This article describes how intermittent hypoxia affects the carotid body function and discusses the cellular, molecular and epigenetic mechanisms underlying the exaggerated chemoreflex.

Sleep disordered breathing in bronchopulmonary dysplasia

BACKGROUND

There are limited data on the effect of bronchopulmonary dysplasia (BPD) on sleep disordered breathing (SDB). We hypothesized that both the severity of prematurity and BPD would increase the likelihood of SDB in early childhood. Our secondary aim was to evaluate the association of demographic factors on the development of SDB.

METHODS

This is a retrospective study of patient factors and overnight polysomnogram (PSG) data of children enrolled in our BPD registry between 2008 and 2015. Association between PSG results and studied variables was assessed using multiple linear regression analysis.

RESULTS

One-hundred-forty children underwent at least one sleep study on room air. The mean respiratory disturbance index (RDI) was elevated at 9.9 events/hr (SD: 10.1). The mean obstructive apnea-hypopnea index (OAHI) was 6.5 (9.1) events/hr and the mean central event rate of 3.0 (3.7) events/hr. RDI had decreased by 22% or 1.5 events/hour (95%CI: 0.6, 1.9) with each year of age (P = 0.005). Subjects with more severe respiratory disease had 38% more central events (P = 0.02). Infants exposed to secondhand smoke had 2.4% lower (P = 0.04) oxygen saturation nadirs and a pattern for more desaturation events. Non-white subjects were found to have 33% higher OAHI (P = 0.05), while white subjects had a 61% higher rate of central events (P < 0.001).

CONCLUSIONS

RDI was elevated in a selected BPD population compared to norms for non-preterm children. BPD severity, smoke exposure, and race may augment the severity of SDB. RDI improved with age but was still elevated by age 4, suggesting that this population is at risk for the sequelae of SDB.

Sleep related breathing disorders and indications for polysomnography in preterm infants

There is a range of breathing problems which occur and may persist in preterm infants, such as central apneas, obstructive apneas and periodic breathing. Preterm infants may also suffer from respiratory distress syndrome and chronic lung disease necessitating prolonged use of oxygen therapy after discharge from the hospital. Due to these persistent breathing pattern abnormalities in preterm infants, there is a higher risk of altered sleep and apparent life threatening events. Polysomnography can be a helpful tool to identify those infants who have abnormalities in their breathing pattern, to identify those infants who have an increased risk to get a sleep related breathing event at home and to decide about the discontinuation of oxygen therapy.

Gender Affects Long-Term Neurological Outcome of Neonates

OBJECTIVE

We evaluated the possible association between fetal gender and long-term pediatric neurological morbidity.

METHODS

We performed a population-based retrospective cohort analysis comparing the risk of long-term neurological morbidity (up to age 18 years) of children born during the years 1991 to 2013 according to their gender. Neurological morbidity evaluated included hospitalizations in childhood involving pervasive developmental disorder, obstructive sleep apnea, cerebral palsy, epilepsy, and infantile spasms and disorders of eating as recorded in the hospital files. Multiple pregnancies and fetal congenital malformations were excluded. Kaplan-Meier survival curves were constructed to compare the cumulative neurological morbidity over the study period. A Cox proportional hazards model was used to control for obstetrical confounders, including gestational age at birth, birth weight, and maternal factors.

RESULTS

During the study period, 240,953 newborns were included in the long-term analysis: 51.0% (n = 122,840) males and 49.0% (n = 118,113) females. Hospitalizations for neurological problems (up to age 18 years) were significantly more common in males compared with females (1.1% vs 0.8%, respectively, odds ratio 1.31, 95% confidence interval 1.2 to 1.4, P < 0.001). Specifically, pervasive developmental disorder and obstructive sleep apnea were found to be significantly more common in males, and cerebral palsy reached borderline significance (0.1% vs 0.04%, odds ratio 1.39, 95% confidence interval 0.9 to 1.9, P = 0.06). The Kaplan-Meier survival curves demonstrated males to have a significantly higher cumulative incidence of total neurological morbidity as well as of pervasive developmental disorder and obstructive sleep apnea (all log-rank test P values <0.001). In the Cox regression model, male gender exhibited an independent association with long-term neurological morbidity, while adjusting for birth weight, gestational age, and other confounding variables (adjusted hazard ratio 1.29, 95% confidence interval 1.2 to 1.4, P < 0.001).

CONCLUSION

Males are at an increased risk for pediatric neurological morbidity independent of gestational age at birth and birth weight.

Adults born preterm: a review of general health and system-specific outcomes

In this review of 126 publications, we report that an overwhelming majority of adults born at preterm gestations remain healthy and well. However, a small, but a significant fraction of them remain at higher risk for neurological, personality and behavioural abnormalities, cardio-pulmonary functional limitations, systemic hypertension and metabolic syndrome compared to their term-born counterparts. The magnitude of increased risk differed across organ systems and varied across reports. The risks were proportional to the degree of prematurity at birth and seemed to occur more frequently among preterm infants born in the final two decades of the 20th century and later. These findings have considerable public health and clinical practice relevance.

CONCLUSION

Preterm birth needs to be considered a chronic condition, with a slight increase in the risk for long-term morbidities among adults born preterm. Therefore, obtaining a history of gestational age and weight at birth should be a routine part of care for patients of all age groups.

Epigenetic changes by DNA methylation in chronic and intermittent hypoxia

DNA methylation of cytosine residues is a well-studied epigenetic change, which regulates gene transcription by altering accessibility for transcription factors. Hypoxia is a pervasive stimulus that affects many physiological processes. The circulatory and respiratory systems adapt to chronic sustained hypoxia, such as that encountered during a high-altitude sojourn. Many people living at sea level experience chronic intermittent hypoxia (IH) due to sleep apnea, which leads to cardiovascular and respiratory maladaptation. This article presents a brief update on emerging evidence suggesting that changes in DNA methylation contribute to pathologies caused by chronic IH and potentially mediate adaptations to chronic sustained hypoxia by affecting the hypoxia-inducible factor (HIF) signaling pathway.

Early Term Deliveries and the Risk of Pediatric Obstructive Sleep Apnoea in the Offspring

BACKGROUND

Preterm delivery may affect the development of the upper airways resulting in a higher risk of obstructive sleep apnoea (OSA). We investigated whether children born at early term (37-38 6/7 weeks' gestation) are at an increased risk for childhood OSA as compared with those born later.

METHODS

In this population-based cohort analysis all singleton deliveries occurring between 1991-2013 at a single regional tertiary medical centre were included. Gestational age upon delivery was sub-divided into: early preterm (<33 6/7 weeks' gestation), late preterm (34-36 6/7), early term, full term (39-40 6/7), late term (41-41 6/7), and post term (>42 0/7). Incidence of OSA related hospitalizations of the offspring, up to the age of 18 years, was evaluated. A survival curve and a Cox model were used to assess the association.

RESULTS

During the study period 240 953 deliveries met the inclusion criteria. OSA hospitalization (n = 1320) rates decreased as gestational age increased from 1.1% in the early preterm group, 0.8% in late preterm, 0.7% at early term, 0.5% in full term, 0.4% in late term, to 0.3% in post term born children. In the Cox regression, early term delivery exhibited an increased risk for paediatric OSA (adjusted hazard ratio (HR) 1.3 95% Confidence interval (CI) 1.2, 1.5) while late and post term deliveries were associated with significantly lower OSA risk when compared with full term (HR 0.8 95% CI 0.6, 0.9 and HR 0.6 95% CI 0.4, 0.8, respectively).

CONCLUSIONS

Early term deliveries are associated with higher rates of paediatric OSA, which decrease gradually as gestational age advances.

How do we recognize the child with OSAS?

Obstructive sleep-disordered breathing includes a spectrum of clinical entities with variable severity ranging from primary snoring to obstructive sleep apnea syndrome (OSAS). The clinical suspicion for OSAS is most often raised by parental report of specific symptoms and/or abnormalities identified by the physical examination which predispose to upper airway obstruction (e.g., adenotonsillar hypertrophy, obesity, craniofacial abnormalities, neuromuscular disorders). Symptoms and signs of OSAS are classified into those directly related to the intermittent pharyngeal airway obstruction (e.g., parental report of snoring, apneic events) and into morbidity resulting from the upper airway obstruction (e.g., increased daytime sleepiness, hyperactivity, poor school performance, inadequate somatic growth rate or enuresis). History of premature birth and a family history of OSAS as well as obesity and African American ethnicity are associated with increased risk of sleep-disordered breathing in childhood. Polysomnography is the gold standard method for the diagnosis of OSAS but may not be always feasible, especially in low-income countries or non-tertiary hospitals. Nocturnal oximetry and/or sleep questionnaires may be used to identify the child at high risk of OSAS when polysomnography is not an option. Endoscopy and MRI of the upper airway may help to identify the level(s) of upper airway obstruction and to evaluate the dynamic mechanics of the upper airway, especially in children with combined abnormalities. Pediatr Pulmonol. 2017;52:260-271. © 2016 Wiley Periodicals, Inc.

Neuromodulation of Limb Proprioceptive Afferents Decreases Apnea of Prematurity and Accompanying Intermittent Hypoxia and Bradycardia

BACKGROUND

Apnea of Prematurity (AOP) is common, affecting the majority of infants born at <34 weeks gestational age. Apnea and periodic breathing are accompanied by intermittent hypoxia (IH). Animal and human studies demonstrate that IH exposure contributes to multiple pathologies, including retinopathy of prematurity (ROP), injury to sympathetic ganglia regulating cardiovascular action, impaired pancreatic islet cell and bone development, cerebellar injury, and neurodevelopmental disabilities. Current standard of care for AOP/IH includes prone positioning, positive pressure ventilation, and methylxanthine therapy; these interventions are inadequate, and not optimal for early development.

OBJECTIVE

The objective is to support breathing in premature infants by using a simple, non-invasive vibratory device placed over limb proprioceptor fibers, an intervention using the principle that limb movements trigger reflexive facilitation of breathing.

METHODS

Premature infants (23-34 wks gestational age), with clinical evidence of AOP/IH episodes were enrolled 1 week after birth. Caffeine treatment was not a reason for exclusion. Small vibration devices were placed on one hand and one foot and activated in 6 hour ON/OFF sequences for a total of 24 hours. Heart rate, respiratory rate, oxygen saturation (SpO2), and breathing pauses were continuously collected.

RESULTS

Fewer respiratory pauses occurred during vibration periods, relative to baseline (p<0.005). Significantly fewer SpO2 declines occurred with vibration (p<0.05), relative to control periods. Significantly fewer bradycardic events occurred during vibration periods, relative to no vibration periods (p<0.05).

CONCLUSIONS

In premature neonates, limb proprioceptive stimulation, simulating limb movement, reduces breathing pauses and IH episodes, and lowers the number of bradycardic events that accompany aberrant breathing episodes. This low-cost neuromodulatory procedure has the potential to provide a non-invasive intervention to reduce apnea, bradycardia and intermittent hypoxia in premature neonates.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02641249.

Perinatal Risk Factors Associated with the Obstructive Sleep Apnea Syndrome in School-Aged Children Born Preterm

STUDY OBJECTIVES

The obstructive sleep apnea syndrome (OSAS) is more prevalent in ex-preterm children compared to the general pediatric population. However, it is unknown whether OSAS in ex-preterm children is associated with specific perinatal risk factors. This multicenter cohort study aimed to determine perinatal factors associated with OSAS at school age.

METHODS

197 ex-preterm (500-1,250 g) children aged 5-12 y who participated as neonates in a double-blind, randomized clinical trial of caffeine versus placebo (Caffeine for Apnea of Prematurity) underwent comprehensive ambulatory polysomnography. A negative binomial regression model was used to identify perinatal risk factors associated with OSAS.

RESULTS

19 children had OSAS (9.6%). Chorioamnionitis and multiple gestation were positively associated with OSAS with P values of 0.014 and 0.03, respectively. Maternal white race (P = 0.047) and maternal age (P = 0.002) were negatively associated with OSAS. Other risk factors, such as birth weight, Apgar score at 5 min, antenatal corticosteroids, delivery route, and sex were not significant.

CONCLUSIONS

OSAS is very frequent, and is associated with chorioamnionitis and multiple gestation in ex-preterm children. Those born to older white mothers appear to be protected. We speculate that the former may be due to systemic inflammation and the latter to a higher socio-economic status.

COMMENTARY

A commentary on this article appears in this issue on page 721.

Cardiorespiratory events in preterm infants: interventions and consequences

Stabilization of respiration and oxygenation continues to be one of the main challenges in clinical care of the neonate. Despite aggressive respiratory support including mechanical ventilation, continuous positive airway pressure, oxygen and caffeine therapy to reduce apnea and accompanying intermittent hypoxemia, the incidence of intermittent hypoxemia events continues to increase during the first few months of life. Even with improvements in clinical care, standards for oxygen saturation targeting and modes of respiratory support have yet to be identified in this vulnerable infant cohort. In addition, we are only beginning to explore the association between the incidence and pattern of cardiorespiratory events during early postnatal life and both short- and long-term morbidity including retinopathy of prematurity, growth, sleep-disordered breathing and neurodevelopmental impairment. Part 1 of this review included a summary of lung development and diagnostic methods of cardiorespiratory monitoring. In Part 2 we focus on clinical interventions and the short- and long-term consequences of cardiorespiratory events in preterm infants.

Peripheral chemoreception and arterial pressure responses to intermittent hypoxia

Carotid bodies are the principal peripheral chemoreceptors for detecting changes in arterial blood oxygen levels, and the resulting chemoreflex is a potent regulator of blood pressure. Recurrent apnea with intermittent hypoxia (IH) is a major clinical problem in adult humans and infants born preterm. Adult patients with recurrent apnea exhibit heightened sympathetic nerve activity and hypertension. Adults born preterm are predisposed to early onset of hypertension. Available evidence suggests that carotid body chemoreflex contributes to hypertension caused by IH in both adults and neonates. Experimental models of IH provided important insights into cellular and molecular mechanisms underlying carotid body chemoreflex-mediated hypertension. This article provides a comprehensive appraisal of how IH affects carotid body function, underlying cellular, molecular, and epigenetic mechanisms, and the contribution of chemoreflex to the hypertension.

Obstructive sleep disordered breathing in 2- to 18-year-old children: diagnosis and management

This document summarises the conclusions of a European Respiratory Society Task Force on the diagnosis and management of obstructive sleep disordered breathing (SDB) in childhood and refers to children aged 2-18 years. Prospective cohort studies describing the natural history of SDB or randomised, double-blind, placebo-controlled trials regarding its management are scarce. Selected evidence (362 articles) can be consolidated into seven management steps. SDB is suspected when symptoms or abnormalities related to upper airway obstruction are present (step 1). Central nervous or cardiovascular system morbidity, growth failure or enuresis and predictors of SDB persistence in the long-term are recognised (steps 2 and 3), and SDB severity is determined objectively preferably using polysomnography (step 4). Children with an apnoea-hypopnoea index (AHI) >5 episodes·h(-1), those with an AHI of 1-5 episodes·h(-1) and the presence of morbidity or factors predicting SDB persistence, and children with complex conditions (e.g. Down syndrome and Prader-Willi syndrome) all appear to benefit from treatment (step 5). Treatment interventions are usually implemented in a stepwise fashion addressing all abnormalities that predispose to SDB (step 6) with re-evaluation after each intervention to detect residual disease and to determine the need for additional treatment (step 7).

Adult Behavior in Male Mice Exposed to E-Cigarette Nicotine Vapors during Late Prenatal and Early Postnatal Life

Nicotine exposure has been associated with an increased likelihood of developing attention deficit hyperactivity disorder (ADHD) in offspring of mothers who smoked during pregnancy. The goal of this study was to determine if exposure to E-cigarette nicotine vapors during late prenatal and early postnatal life altered behavior in adult mice.

Epigenetic Regulation of Carotid Body Oxygen Sensing: Clinical Implications

Recurrent apnea with intermittent hypoxia (IH) is a major clinical problem in infants born preterm. Recent epidemiological studies showed that adults who were born preterm exhibit increased incidence of sleep-disordered breathing and hypertension. Thus, apnea of prematurity predisposes individuals to autonomic dysfunction in adulthood. Experimental studies showed that adult rats exposed to IH as neonates exhibit augmented carotid body and adrenal chromaffin cells (AMC) response to hypoxia and irregular breathing with apneas and hypertension. The enhanced hypoxic sensitivity of the carotid body and AMC in adult rats exposed to neonatal IH was associated with increased oxidative stress, decreased expression of genes encoding anti-oxidant enzymes, and increased expression of pro-oxidant enzymes. Epigenetic mechanisms including DNA methylation leads to long-term changes in gene expression. The decreased expression of the Sod2 gene, which encodes the anti-oxidant enzyme, superoxide dismutase 2, was associated with DNA hypermethylation of a single CpG dinucleotide close to the transcription start site. Treating neonatal rats with decitabine, an inhibitor of DNA methylation, during IH exposure prevented the oxidative stress, enhanced hypoxic sensitivity, and autonomic dysfunction in adult rats. These findings suggest that epigenetic mechanisms, especially DNA methylation contributes to neonatal programming of hypoxic sensitivity and the ensuing autonomic dysfunction in adulthood.

Advanced sleep phase in adolescents born preterm

The objective of this article is to evaluate whether sleep patterns and quality differed between adolescents born preterm and term, and to further explore whether differences in sleep patterns were explained by differences in mediating factors such as mood, behavior, or socioeconomic status. Five hundred and one 16- to 19-year-old children in the longitudinal Cleveland Children's Sleep and Health Study cohort underwent overnight polysomnography (PSG), wore wrist actigraphs, and completed sleep logs for 1 week. The modified Epworth Sleepiness Scale, the Adolescent Sleep Hygiene Scale, and the Adolescent Sleep-Wake Scale were used to further assess sleep. Adolescents born preterm demonstrated significantly (p < .05) earlier bed and wake times and sleep midpoints (approximately 22 min after adjusting for demographic and psychosocial factors) by actigraphy. They also had significantly fewer arousals (by PSG), and reported being more rested and alert in the morning, as well as less sleepiness and fatigue. These findings support a growing body of evidence that perinatal factors may influence sleep phenotypes later in life. These factors may reflect developmental influences, as well as the influence of parenting styles on children's sleep.

Cell-based therapies for the preterm infant

The severely preterm infant receives a multitude of life-saving interventions, many of which carry risks of serious side effects. Cell therapy is an important and promising arm of regenerative medicine that may address a number of these problems. Most forms of cellular therapy use stem/progenitor cells or stem-like cells, which have the capacity to migrate, engraft and exert anti-inflammatory effects. Although some of these cell-based therapies have made their way to clinical trials in adults, little headway has been made in the neonatal patient group. This review discusses the efficacy of cell therapy in preclinical studies to date and their potential applications to diseases that afflict many prematurely born infants. Specifically, we identify the major hurdles that must be overcome before cell therapies can be safely used in the neonatal intensive care unit.

Sleep duration and insulin resistance in individuals without type 2 diabetes: the PPP-Botnia study

INTRODUCTION

Both short and long sleep duration may increase risk of type 2 diabetes (diabetes). We studied if short and long sleep durations were associated with insulin resistance (IR) and insulin secretion in individuals without diabetes, and if the associations remained after we excluded individuals who reported more frequent and severe complaints of sleep apnea and insomnia.

PARTICIPANTS AND METHODS

An oral glucose tolerance test (OGTT) was performed for 722 adults without diabetes. Indices of IR and insulin secretion were calculated. Sleep duration and complaints of sleep apnea and insomnia were self-reported.

RESULTS

In comparison to average sleepers (6-9 h/night), short sleepers (< 6 h/night) had higher 120-min insulin and AUC glucose, and long sleepers (≥ 9 h/night) had higher fasting and 120-min insulin, 120-min glucose, and HOMAIR and lower Insulin Sensitivity Index. After adjusting for confounders and after excluding individuals who reported more frequent and severe complaints of sleep apnea and insomnia, long sleep duration remained significantly associated with IR and insulin secretion.

DISCUSSION

Long but not short sleep duration is associated with IR and insulin secretion in individuals without diabetes whether or not accompanied by sleep complaints. Long sleepers may benefit from targeted preventions and interventions that aim at reducing risk of future diabetes.