Preterm birth and childhood wheezing disorders: a systematic review and meta-analysis

Respiratory morbidity in preschool and school-age children born very preterm and its association with parents' health-related quality of life and family functioning

The purpose of this study is to describe the prevalence and severity of respiratory symptoms in children born very preterm and to assess their association with parents' health-related quality of life (HRQoL) and family functioning. We conducted a cross-sectional study and recruited children born less than 32 weeks' gestation between January 2006 and December 2019, in the greater Zurich area, Switzerland. Between May and December 2021, parents were invited to complete an online survey for their preterm child and for a control term born (≥ 37 weeks' gestation) sibling aged 1 to 18 years. We used a validated questionnaire to assess respiratory symptoms and the Pediatrics Quality of Life Family Impact Module (PedsQL FIM) to assess parents' HRQoL and family functioning. The survey was completed for 616 very preterm children (99 with bronchopulmonary dysplasia (BPD)) and 180 controls. Girls made up 45% (46% in controls) of the sample, and 63% (60% in controls) of participants were aged 6 to 18 years (school-age). Very preterm children reported a higher risk of respiratory symptoms than controls, especially preschoolers and those with moderate-to-severe BPD. Parents of children with "mild" and "moderate-severe" respiratory symptoms had on average -3.9 (95%CI: -6.6 to -1.1) and -8.2 (-11.2 to -5.2) lower PedsQL FIM total score, respectively, than parents of children with no symptoms. The same pattern was observed after stratifying by age categories.  Conclusions: Our study suggests that respiratory morbidity in very preterm children has a negative impact on parents' HRQoL and family functioning, even beyond the first years of life. What is Known: • The burden of respiratory morbidity associated with very premature birth is high and last far beyond the neonatal period. • Respiratory morbidity contributes to lower health-related quality of life (HRQoL) in parents of very preterm children in early infancy. What is New: • Respiratory morbidity in very preterm children has a negative impact on parents' HRQoL and family functioning beyond the first years of life. • Parents of very preterm children with moderate and severe respiratory symptoms are the ones who report lower scores, both for preschool and school-age children.

Allergic diseases in India - Prevalence, risk factors and current challenges

Epidemiological studies have shown a rise in the prevalence of allergic diseases in India during the last two decades. However, recent evidence from the Global Asthma Network study has observed a decrease in allergic rhinitis, asthma and atopic dermatitis in children. Still, with a population over 1.3 billion, there is a huge burden of allergic rhinitis, asthma and atopic dermatitis, and this is compounded by an unmet demand for trained allergy specialists and poor health service framework. There is wide variation in the prevalence of allergic diseases between different geographical locations in India, and the reasons are unclear at present. This may at least in part be attributable to considerable heterogeneity in aero-biology, weather, air pollution levels, cultural and religious factors, diet, socioeconomic strata and literacy. At present, factors enhancing risks and those protecting from development of atopy and allergic diseases have not been well delineated, although there is some evidence for the influence of genetic factors alongside cultural and environmental variables such as diet, exposure to tobacco smoke and air pollution and residence in urban areas. This narrative review provides an overview of data from India regarding epidemiology, risk factors and genetics and highlights gaps in evidence as well as areas for future research.

Early-life hyperoxia-induced Flt3L drives neonatal lung dendritic cell expansion and proinflammatory responses

Premature infants with chronic lung disease, bronchopulmonary dysplasia (BPD), develop recurrent cough and wheezing following respiratory viral infections. The mechanisms driving the chronic respiratory symptoms are ill-defined. We have shown that hyperoxic exposure of neonatal mice (a model of BPD) increases the activated lung CD103+ dendritic cells (DCs) and these DCs are required for exaggerated proinflammatory responses to rhinovirus (RV) infection. Since CD103+ DC are essential for specific antiviral responses and their development depends on the growth factor Flt3L, we hypothesized that early-life hyperoxia stimulates Flt3L expression leading to expansion and activation of lung CD103+ DCs and this mediates inflammation. We found that hyperoxia numerically increased and induced proinflammatory transcriptional signatures in neonatal lung CD103+ DCs, as well as CD11bhi DCs. Hyperoxia also increased Flt3L expression. Anti-Flt3L antibody blocked CD103+ DC development in normoxic and hyperoxic conditions, and while it did not affect the baseline number of CD11bhi DCs, it neutralized the effect of hyperoxia on these cells. Anti-Flt3L also inhibited hyperoxia-induced proinflammatory responses to RV. In tracheal aspirates from preterm infants mechanically-ventilated for respiratory distress in the first week of life levels of FLT3L, IL-12p40, IL-12p70 and IFN-γ were higher in infants who went on to develop BPD and FLT3L levels positively correlated with proinflammatory cytokines levels. This work highlights the priming effect of early-life hyperoxia on lung DC development and function and the contribution of Flt3L in driving these effects.

Maternal and neonatal risk factors of asthma in children: Nationwide population based study

BACKGROUND

Small population group-based cohorts have found that perinatal factors may contribute to the development of asthma in children. We aimed to investigate maternal and neonatal risk factors for the asthma phenotypes using two databases from the Taiwan's Maternal and Child Health Database (TMCHD) and the National Health Insurance Research Database (NHIRD).

METHODS

Perinatal data was obtained from 2004 to 2008 in the TMCHD and linked the NHIRD to obtain relevant medical information regarding maternal and neonatal risk factors of three asthma phenotypes which were identified as transient early asthma, persistent asthma, and late-onset asthma. A multivariate logistic regression analysis was conducted to adjust for covariates.

RESULTS

The percentage of non-asthmatic patients was 77.02% and asthmatic (transient early asthma, late onset asthma, and persistent asthma) patients were 8.96%, 11.64%, and 2.42%, respectively. Maternal risk factors-including Cesarean section, maternal asthma, maternal allergic rhinitis (AR), and premature rupture of membranes-and neonatal risk factors, such as male gender, gestational age 29-37 weeks, ventilator use, antibiotics use, AR, and atopic dermatitis, were associated with the development of these three asthma phenotypes. Twins and a gestational age of 28 weeks or less premature were associated with the development of transient early asthma and persistent asthma, but not late onset asthma. Triplets and above were associated with the development of transient early asthma, but not late onset or persistent asthma.

CONCLUSION

Various asthma phenotypes have different risk factors; therefore, their distinct risk factors should be identified in order to early diagnosis and treatment.

Relation of Maternal Pre-Pregnancy Factors and Childhood Asthma: A Cross-Sectional Survey in Pre-School Children Aged 2-5 Years Old

Background and Objectives: Asthma constitutes a constant, prolonged, inflammation-related pulmonary disorder in childhood with serious public health concerns. Several maternal risk factors can enhance the prevalence of its development in this stage of life; however, the currently available data remain contradictory and/or inconsistent. We aim to evaluate the potential impacts of mothers' sociodemographic, anthropometric and prenatal and perinatal factors on the prevalence of developing asthma in pre-school children. Materials and Methods: This is a retrospective cross-sectional survey, which includes 5133 women and their matched pre-school children. Childhood asthma was diagnosed using validated questionnaires. Statistical analysis was accomplished to evaluate whether maternal sociodemographic, anthropometric and prenatal and perinatal factors can increase the probability of childhood asthma in pre-school age. Results: A prevalence of 4.5% of childhood asthma was recorded in pre-school age. Maternal age and pre-pregnancy overweight and obesity, caesarean section, gestational diabetes and hypertension and not breastfeeding were associated with childhood asthma after adjustment for multiple confounding factors. Conclusion: Our research showed that several maternal factors increase the prevalence of childhood asthma in pre-school age. Suitable and effective health policies and strategies should be taken into account to confront the predominant maternal factors that increase its prevalence in pre-school age.

Association Between Aluminum Exposure From Vaccines Before Age 24 Months and Persistent Asthma at Age 24 to 59 Months

OBJECTIVE

To assess the association between cumulative aluminum exposure from vaccines before age 24 months and persistent asthma at age 24 to 59 months.

METHODS

A retrospective cohort study was conducted in the Vaccine Safety Datalink (VSD). Vaccination histories were used to calculate cumulative vaccine-associated aluminum in milligrams (mg). The persistent asthma definition required one inpatient or 2 outpatient asthma encounters, and ≥2 long-term asthma control medication dispenses. Cox proportional hazard models were used to evaluate the association between aluminum exposure and asthma incidence, stratified by eczema presence/absence. Adjusted hazard ratios (aHR) and 95% confidence intervals (CI) per 1 mg increase in aluminum exposure were calculated, adjusted for birth month/year, sex, race/ethnicity, VSD site, prematurity, medical complexity, food allergy, severe bronchiolitis, and health care utilization.

RESULTS

The cohort comprised 326,991 children, among whom 14,337 (4.4%) had eczema. For children with and without eczema, the mean (standard deviation [SD]) vaccine-associated aluminum exposure was 4.07 mg (SD 0.60) and 3.98 mg (SD 0.72), respectively. Among children with and without eczema, 6.0% and 2.1%, respectively, developed persistent asthma. Among children with eczema, vaccine-associated aluminum was positively associated with persistent asthma (aHR 1.26 per 1 mg increase in aluminum, 95% CI 1.07, 1.49); a positive association was also detected among children without eczema (aHR 1.19, 95% CI 1.14, 1.25).

CONCLUSION

In a large observational study, a positive association was found between vaccine-related aluminum exposure and persistent asthma. While recognizing the small effect sizes identified and the potential for residual confounding, additional investigation of this hypothesis appears warranted.

Prematurity-associated wheeze: current knowledge and opportunities for further investigation

Prematurity-associated wheeze is a common complication of preterm birth, with significant impact on the health and healthcare utilization of former preterm infants. This wheezing phenotype remains poorly understood and difficult to predict. This review will discuss the current state of the literature on prematurity-associated wheeze. We will discuss etiology and pathophysiology, and offer two conceptual models for the pathogenesis of this complex condition. This review will also identify current methods of ascertainment, and discuss the strengths and limitations of each. We will explore research-backed approaches to prevention and management, and finally suggest both pre-clinical and clinical avenues for investigation. An in-depth understanding of prematurity-associated wheeze will aid clinicians in its diagnosis and management, and inspire scientists to pursue much-needed further study into causes and prevention of this common and impactful condition. IMPACT: There is no recent, concise review on the current state of research on prematurity-associated wheeze, which is a rapidly evolving area of study. This article highlights causal models of wheeze, methods of ascertainment, management strategies for the clinician, and opportunities for further research for the physician scientist.

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

Childhood overweight and obesity and abnormal birth anthropometric measures are associated with a higher prevalence of childhood asthma in pre-school age

OBJECTIVES

Childhood asthma is one of the most common non-communicable diseases in the world. Several perinatal and postnatal factors have been associated with increased risk of developing childhood asthma. The present study aims to assess whether childhood overweight and obesity and abnormal birth anthropometric measures affect the risk of developing childhood asthma in preschool age.

METHODS

In this study, 5215 preschool children at the age of 2-5 years were enrolled after applying several inclusion and exclusion criteria and they examined whether they present asthma symptoms. Non-adjusted and adjusted statistical analysis was performed to assess whether perinatal and postnatal factors increase the risk of developing childhood asthma.

RESULTS

A prevalence of 4.5% of childhood asthma was recorded. Among children diagnosed with asthma, 19.4% were affected by overweight and 13.9% were obese. Childhood overweight/obesity was indepedently associated with a 76% higher risk of childhood asthma than normal weight. Abnormal birth anthropometric measures, i.e. birth weight, length, and head circumference, were independently associated with higher odds (87%, 29%, and 23%, respectively) of childhood asthma than normal ranges.

CONCLUSIONS

This is a cross-sectional, nationally representative study which supported evidence that childhood overweight/obesity and abnormal birth anthropometric measures may independently increase the risk of childhood asthma in preschool age. Emergent health policies and strategies are recommended to promote a healthy lifestyle, preventing childhood obesity at the early stages of life.

The causal association between maternal smoking around birth on childhood asthma: A Mendelian randomization study

To explore the causal relationship between maternal smoking around birth and childhood asthma using Mendelian randomization (MR). Using the data from large-scale genome-wide association studies, we selected independent genetic loci closely related to maternal smoking around birth and maternal diseases as instrumental variables and used MR methods. In this study, we considered the inverse variance weighted method (MR-IVW), weighted median method, and MR-Egger regression. We investigated the causal relationship between maternal smoking around birth and maternal diseases in childhood asthma using the odds ratio (OR) as an evaluation index. Multivariable MR (MVMR) included maternal history of Alzheimer's disease, illnesses of the mother: high blood pressure and illnesses of the mother: heart diseaseas covariates to address potential confounding. Sensitivity analyses were evaluated for weak instrument bias and pleiotropic effects. It was shown with the MR-IVW results that maternal smoking around birth increased the risk of childhood asthma by 1.5% (OR = 1.0150, 95% CI: 1.0018-1.0283). After the multivariable MR method was used to correct for relevant covariates, the association effect between maternal smoking around birth and childhood asthma was still statistically significant (P < 0.05). Maternal smoking around birth increases the risk of childhood asthma.

Human milk feeding and wheeze in Black infants born preterm

OBJECTIVES

To determine the association between human milk exposure at 3 months corrected gestational age and recurrent wheeze in preterm Black infants.

METHODS

This is a secondary analysis of data from the D-Wheeze trial (ClinicalTrials.gov identifier NCT01601847). Associations between human milk feeding at 3 months corrected age and wheezing outcomes were examined by generalized linear models.

RESULTS

Exclusively human milk fed infants (n = 13) had significantly fewer wheezing episodes than formula fed infants (n = 230) (IRR (95% CI) = 0.25 (0.07, 0.89), p = 0.03). There were no hospitalizations in infants receiving exclusive human milk. Receiving any human milk was associated with decreased odds of hospitalization by 12 months corrected age (OR (95% CI) = 0.12 (0.02, 0.79), p = 0.03).

CONCLUSIONS

Exclusive human milk feeding at three months corrected gestational age is associated with decreased number of wheezing episodes in the first year of life in preterm Black infants.

Allergen Content and Protease Activity in Milk Feeds from Mothers of Preterm Infants

Rationale: There is little information regarding the allergen content of milk feeds in the preterm population. Previous studies have not performed a broad analysis of the allergenic peptide content and protease activity of milk feeds in this population. Methods: To evaluate feasibility, we initially performed mass spectrometry on 4 human milk (HM) samples (2 term and 2 preterm) from the Mommy's Milk Human Milk Biorepository (HMB) and analyzed the results against the University of Nebraska FASTA database and UniProt for a total of 2,211 protein sequences. We then further analyzed five samples from the Microbiome, Atopy, and Prematurity (MAP) study including peptidomic and protease activity analysis. Results: Each HMB sample had between 806 and 1,007 proteins, with 37-44 nonhuman proteins/sample encompassing 26 plant and animal species. In the preterm MAP samples, 784 digested nonhuman proteins were identified, 30 were nonbovine in origin. Proteins from 23 different species including aeroallergens, food, and contact allergens were identified. Protease activity was highest in HM samples without human milk fortifier and lowest in preterm formula. Conclusions: These findings represent the first preterm milk feed mass spectrometry and protease analysis with identification of known allergenic proteins to food, contact, and aeroallergens. These results raise questions of whether the composition of milk feeds in the neonatal intensive care unit impact the development of atopic disease in the preterm population and whether the complex interaction between allergens, proteases, and other HM components can serve to induce sensitization or tolerance to allergens in infants. Clinical Trial Registration Number: NCT04835935.

Preterm birth and prescriptions for cardiovascular, antiseizure, antibiotics and antiasthmatic medication in children up to 10 years of age: a population-based data linkage cohort study across six European regions

OBJECTIVES

Preterm children are exposed to many medications in neonatal intensive care units, but little is known about the effect of prematurity on medication use throughout infancy and childhood. We examined prescriptions of cardiovascular medication (CVM), antiseizure medication (ASM), antiasthmatic medication and antibiotics issued/dispensed in the first 10 years of life for very and moderately preterm children compared with term.

DESIGN

Population-based data linkage cohort study linking information from birth records to prescription records.

SETTING

Six registries from five countries in the EUROlinkCAT study.

PARTICIPANTS

The study population included 1 722 912 children, of whom 10 820 (0.6%) were very preterm (<32 weeks gestational age (GA)), 92 814 (5.4%) were moderately preterm (32-36 weeks GA), 1 606 643 (93.3%) were born at term (≥37 weeks GA) and 0.7% had missing GA. Children with major or minor congenital anomalies were excluded (including patent ductus arteriosus).

MAIN OUTCOME MEASURES

Relative risk (RR) of receiving a prescription for CVM, ASM, antiasthmatic and antibiotics.

RESULTS

Very preterm children had a higher RR of receiving a prescription for CVM and ASM than preterm children. For all preterm children, the RR of having a CVM prescription was 3.58 (95% CI 2.06 to 6.23); 2.06 (95% CI 1.73 to 2.41) for ASM; 1.13 (95% CI 0.99 to 1.29) for antiasthmatics and 0.96 (95% CI 0.93 to 0.99) for antibiotics in the first year of life. Increased prescription of CVM, ASM and antiasthmatics persisted for all 10 years of follow-up. Although the RR was highest for CVM and ASM, in absolute numbers more children received prescriptions for antibiotics (42.34%, 95% CI 38.81% to 45.91%) and antiasthmatics (28.40%, 95% CI 16.07% to 42.649%) than for CVM (0.18%, 95% CI 0.12% to 0.25%) and ASM (0.16%, 95% CI 0.13% to 0.20%) in the first year of life.

CONCLUSION

Preterm children had a higher risk of being prescribed/dispensed CVM, ASM and antiasthmatics up to age 10. This study highlights a need for further research into morbidity beyond age 10.

Daycare Attendance is Linked to Increased Risk of Respiratory Morbidities in Children Born Preterm with Bronchopulmonary Dysplasia

OBJECTIVES

To test the hypothesis that daycare attendance among children with bronchopulmonary dysplasia (BPD) is associated with increased chronic respiratory symptoms and/or greater health care use for respiratory illnesses during the first 3 years of life.

STUDY DESIGN

Daycare attendance and clinical outcomes were obtained via standardized instruments for 341 subjects recruited from 9 BPD specialty clinics in the US. All subjects were former infants born preterm (<34 weeks) with BPD (71% severe) requiring outpatient follow-up between 0 and 3 years of age. Mixed logistic regression models were used to test for associations.

RESULTS

Children with BPD attending daycare were more likely to have emergency department visits and systemic steroid usage. Children in daycare up to 3 years of age also were more likely to report trouble breathing, having activity limitations, and using rescue medications when compared with children not in daycare. More severe manifestations were found in children attending daycare between 6 and 12 months of chronological age.

CONCLUSIONS

In this study, children born preterm with BPD who attend daycare were more likely to visit the emergency department, use systemic steroids, and have chronic respiratory symptoms compared with children not in daycare, indicating that daycare may be a potential modifiable risk factor to minimize respiratory morbidities in children with BPD during the preschool years.

Long-term expiratory airflow of infants born moderate-late preterm: A systematic review and meta-analysis

BACKGROUND

Moderate-late preterm (MLP; 32 to <37 weeks' gestation) birth is associated with reduced expiratory airflow during child, adolescent and adult years. However, some studies have reported only minimal airflow limitation and hence it is unclear if clinical assessment in later life is warranted. Our aim was to compare maximal expiratory airflow in children and adults born MLP with term-born controls, and with expected norms.

METHODS

We systematically reviewed studies reporting z-scores for spirometric indices (forced expired volume in 1 second [FEV₁], forced vital capacity [FVC], FEV₁/FVC ratio and forced expiratory flow at 25-75% of FVC [FEF_25-75%]) from participants born MLP aged five years or older, with or without a term-born control group from 4 databases (MEDLINE, CINAHL, Embase, Emcare). Publications were searched for between the 22^nd of September 2021 to the 29^th of September 2021. A meta-analysis of eligible studies was conducted using a random effects model. The study protocol was published in PROSPERO (CRD #42021281518).

FINDINGS

We screened 4970 articles and identified 18 relevant studies, 15 of which were eligible for meta-analysis (8 with term-born controls and 7 without). Compared with controls, MLP participants had lower z-scores (mean difference [95% confidence interval] I²) for FEV₁: -0.22 [-0.35, -0.09] 49.3%, FVC: -0.23 [-0.4, -0.06] 71.8%, FEV₁/FVC: -0.11 [-0.20 to -0.03] 9.3% and FEF_25-75%: -0.27 [-0.41 to -0.12] 21.9%. Participants born MLP also had lower z-scores, on average, when compared with a z-score of 0 (mean [95% CI] I²) for FEV₁: -0.26 [-0.40 to -0.11] 85.2%, FVC: -0.18 [-0.34 to -0.02] 88.3%, FEV₁/FVC: -0.24 [-0.43 to -0.05] 90.5% and FEF_25-75%: -0.33 [-0.54 to -0.20] 94.7%.

INTERPRETATION

Those born MLP had worse expiratory airflows than those born at term, and compared with norms, although reductions were modest. Clinicians should be aware that children and adults born MLP may be at higher risk of obstructive lung disease compared with term-born peers.

FUNDING

This work is supported by grants from the National Health and Medical Research Council (Centre of Research Excellence #1153176, Project grant #1161304); Medical Research Future Fund (Career Development Fellowship to J.L.Y Cheong #1141354) and from the Victorian Government's Operational Infrastructure Support Programme. C. Du Berry's PhD candidature is supported by the Melbourne Research Scholarship and the Centre of Research Excellence in Newborn Medicine.

Association between maternal depression and neonatal outcomes: Evidence from a survey of nationally representative longitudinal studies

Background and aims

Maternal depression before and after delivery has dramatically increased in China. Therefore, this study aimed to examine the association between antepartum and postpartum depression and neonatal outcomes.

Design

A population-based retrospective cohort study.

Setting

China.

Participants

Data were obtained from China Family Panel Studies (CFPS). Different mother-child/infant samples were included in this study. Mother in CFPS2012 and CFPS2016 were linked with 1-2-year-old children in CFPS2014 and CFPS2018, respectively. Besides, and mothers in CFPS2012, CFPS2016, and CFPS2018 were linked with 0-1-year-old infants in CFPS2012, CFPS2016, and CFPS2018, respectively.

Methods

Maternal depression was measured using the Center for Epidemiologic Studies Depression Scale. The neonatal outcomes included duration of gestational days, preterm birth, birth weight, birth weight z-score, weight, weight z-score, illness in the past month, and hospitalization in the past year. Propensity score matching was used to balance maternal, family, and infant/child characteristics between the maternal depression and non-maternal depression groups.

Results

Multivariable regression analysis of matched samples estimated that antepartum depression was associated with a shorter duration of gestation by 3.99 days (95% confidence interval [CI] = -7.21, -0.78). The association between antepartum depression and preterm birth, birth weight and birth weight z-score were not statistically significant. Postpartum depression was associated with more episodes of illness in the last month by 0.23 times (95% CI = 0.11, 0.36) and a higher odd of hospitalization in the previous year (OR = 1.59, 95% CI = 1.15, 2.20). The association between postpartum depression and weight or the weight z-score was not significant.

Conclusion

Maternal depression appears to be associated with worse neonatal outcomes.

Impaired exercise outcomes with significant bronchodilator responsiveness in children with prematurity-associated obstructive lung disease

INTRODUCTION

Preterm-born children have their normal in-utero lung development interrupted, thus are at risk of short- and long-term lung disease. Spirometry and exercise capacity impairments have been regularly reported in preterm-born children especially those who developed chronic lung disease of prematurity (CLD) in infancy. However, specific phenotypes may be differentially associated with exercise capacity. We investigated exercise capacity associated with prematurity-associated obstructive (POLD) or prematurity-associated preserved ratio of impaired spirometry (pPRISm) when compared to preterm- and term-controls with normal lung function.

MATERIALS AND METHODS

Preterm- and term-born children identified through home screening underwent in-depth lung function and cardiorespiratory exercise testing, including administration of postexercise bronchodilator, as part of the Respiratory Health Outcomes in Neonates (RHiNO) study.

RESULTS

From 241 invited children, aged 7-12 years, 202 underwent exercise testing including 18 children with POLD (percent predicted (%)FEV₁ and FEV₁ /FVC < LLN); 12 pPRISm (%FEV₁  < LLN and FEV₁ /FVC ≥ LLN), 106 preterm-controls (PT_c , %FEV₁  ≥ LLN) and 66 term-controls (T_c , %FEV₁  > 90%). POLD children had reduced relative workload, peak O₂ uptake, CO₂ production, and minute ventilation compared to T_c , and used a greater proportion of their breathing reserve compared to both control groups. pPRISm and PT_c children also had lower O₂ uptake compared to T_c . POLD children had the greatest response to postexercise bronchodilator, improving their %FEV₁ by 19.4% (vs 6.3%, 6% 6.3% in pPRISm PT_c, T_c , respectively; p < .001).

CONCLUSION

Preterm-born children with obstructive airway disease had the greatest impairment in exercise capacity, and significantly greater response to postexercise bronchodilators. These classifications can be used to guide treatment in children with POLD.

AZTEC-azithromycin therapy for prevention of chronic lung disease of prematurity: a statistical analysis plan for clinical outcomes

BACKGROUND

The AZTEC trial is a multi-centre, randomised, placebo-controlled trial of azithromycin to improve survival without development of chronic lung disease of prematurity (CLD) in preterm infants. The statistical analysis plan for the clinical outcomes of the AZTEC trial is described.

METHODS AND DESIGN

A double-blind, randomised, placebo-controlled trial of a 10-day course of intravenous azithromycin (20 mg/kg for 3 days; 10 mg/kg for 7 days) administered to preterm infants born at < 30 weeks' gestational age across UK tertiary neonatal units. Following parental consent, infants are randomly allocated to azithromycin or placebo, with allocated treatment starting within 72 h of birth. The primary outcome is survival without moderate/severe CLD at 36 weeks' postmenstrual age (PMA). Serial respiratory fluid and stool samples are being collected up to 21 days of life. The target sample size is 796 infants, which is based on detecting a 12% absolute difference in survival without moderate/severe CLD at 36 weeks' PMA (90% power, two-sided alpha of 0.05) and includes 10% loss to follow-up.

RESULTS

Baseline demographic and clinical characteristics will be summarised by treatment arm and in total. Categorical data will be summarised by numbers and percentages. Continuous data will be summarised by mean, standard deviation, if data are normal, or median, interquartile range, if data are skewed. Tests of statistical significance will not be undertaken for baseline characteristics. The primary analysis, on the intention to treat (ITT) population, will be analysed using multilevel logistic regression, within a multiple imputation framework. Adjusted odds ratios, 95% confidence intervals, and p-values will be presented. For all other analyses, the analysis population will be based on the complete case population, which is a modified ITT population. All analyses will be adjusted for gestational age and treatment arm and account for any clustering by centre and/or multiple births as a random effect.

CONCLUSION

We describe the statistical analysis plan for the AZTEC trial, including the analysis principles, definitions of the key clinical outcomes, methods for primary analysis, pre-specified subgroup analysis, sensitivity analysis, and secondary analysis. The plan has been finalised prior to the completion of recruitment.

TRIAL REGISTRATION

ISRCTN registry ISRCTN11650227. Registered on 31 July 2018.

Age-specific associations of early daycare, older siblings, severe airway infection, and preterm birth with subsequent atopic diseases

BACKGROUND

The effects of infection and developmental adaptations in infancy on the prevalence of subsequent atopy-related diseases at different ages during childhood are not fully determined. This study aims to examine the similarities and differences in the age-specific association of asthma, allergic rhinitis/conjunctivitis, and atopic dermatitis with early-life infection-related factors (i.e., daycare, older siblings, and severe airway infection) and developmental adaptations (i.e., preterm birth and rapid weight gain) in children.

METHODS

In this longitudinal cohort study (n = 47,015), children were followed from 0.5 to 11 years. The potential risks and protective factors, including daycare attendance at 0.5 years, existence of older siblings, history of hospitalization due to cold/bronchitis/bronchiolitis/pneumonia during 0.5-1.5 years, preterm birth, and rapid weight gain in the first 2.5 years, were assessed using multivariable logistic regression with adjustments for potential confounders.

RESULTS

A protective association was observed between early-life daycare attendance and asthma at 5.5-9 years, which disappeared after 10 years. A protective association was also noted throughout childhood between early daycare attendance and older siblings with allergic rhinitis/conjunctivitis. However, the association between early daycare and atopic dermatitis was found to be risky during childhood. In contrast, the early-life history of hospitalization owing to cold/bronchitis/bronchiolitis/pneumonia was identified to be a risk factor for developing both asthma and allergic rhinitis/conjunctivitis. Preterm birth was a significant risk factor for childhood asthma.

CONCLUSION

Different age-specific patterns were demonstrated in the relationship between early daycare, severe airway infection, preterm birth, and atopy-related diseases in childhood.

Diagnosis and management of asthma in children

Asthma is the the most common chronic respiratory condition of childhood worldwide, with around 14% of children and young people affected. Despite the high prevalence, paediatric asthma outcomes are inadequate, and there are several avoidable deaths each year. Characteristic asthma features include wheeze, shortness of breath and cough, which are typically triggered by a number of possible stimuli. There are several diagnostic challenges, and as a result, both overdiagnosis and underdiagnosis of paediatric asthma remain problematic.Effective asthma management involves a holistic approach addressing both pharmacological and non-pharmacological management, as well as education and self-management aspects. Working in partnership with children and families is key in promoting good outcomes. Education on how to take treatment effectively, trigger avoidance, modifiable risk factors and actions to take during acute attacks via personalised asthma action plans is essential.This review aimed to provide an overview of good clinical practice in the diagnosis and management of paediatric asthma. We discuss the current diagnostic challenges and predictors of life-threatening attacks. Additionally, we outline the similarities and differences in global paediatric asthma guidelines and highlight potential future developments in care. It is hoped that this review will be useful for healthcare providers working in a range of child health settings.

Time-Specific Factors Influencing the Development of Asthma in Children

Susceptibility to asthma is complex and heterogeneous, as it involves both genetic and environmental insults (pre- and post-birth) acting in a critical window of development in early life. According to the Developmental Origins of Health and Disease, several factors, both harmful and protective, such as nutrition, diseases, drugs, microbiome, and stressors, interact with genotypic variation to change the capacity of the organism to successfully adapt and grow in later life. In this review, we aim to provide the latest evidence about predictive risk and protective factors for developing asthma in different stages of life, from the fetal period to adolescence, in order to develop strategic preventive and therapeutic interventions to predict and improve health later in life. Our study shows that for some risk factors, such as exposure to cigarette smoke, environmental pollutants, and family history of asthma, the evidence in favor of a strong association of those factors with the development of asthma is solid and widely shared. Similarly, the clear benefits of some protective factors were shown, providing new insights into primary prevention. On the contrary, further longitudinal studies are required, as some points in the literature remain controversial and a source of debate.

Respiratory Follow Up of the Premature Neonates-Rationale and Practical Issues

The aim of the review was to present the state of knowledge about the respiratory pathology in former premature neonates (children that were born preterm-before 37 weeks of gestation-and are examined and evaluated after 40 weeks corrected age) other than chronic lung disease, in order to provide reasons for a respiratory follow-up program for this category of patients. After a search of the current evidence, we found that premature infants are prone to long-term respiratory consequences due to several reasons: development of the lung outside of the uterus, leading to dysmaturation of the structures, pulmonary pathology due to immaturity, infectious agents or mechanical ventilation and deficient control of breathing. The medium- to long-term respiratory consequences of being born before term are represented by an increased risk of respiratory infections (especially viral) during the first years of life, a risk of recurrent wheezing and asthma and a decrease in pulmonary volumes and airway flows. Late preterm infants have risks of pulmonary long-term consequences similar to other former premature infants. Due to all the above risks, premature neonates should be followed in an organized fashion, being examined at regular time intervals from discharge from the maternity hospital until adulthood-this could lead to an early detection of the risks and preventive therapies in order to improve their prognosis and assure a normal and productive life. The difficulties related to establishing such programs are represented by the insufficient standardization of the data gathering forms, clinical examinations and lung function tests, but it is our belief that if more premature infants are followed, the experience will allow standards to be established in these fields and the methods of data gathering and evaluation to be unified.

Inhaled Corticosteroids Alone and in Combination With Long-Acting β2 Receptor Agonists to Treat Reduced Lung Function in Preterm-Born Children: A Randomized Clinical Trial

Importance

Decreases in future lung function are a hallmark of preterm birth, but studies for management of decreased lung function are limited.

Objective

To determine whether 12 weeks of treatment with inhaled corticosteroids (ICS) alone or in combination with long-acting β2 agonists (LABA) improves spirometry and exercise capacity in school-aged preterm-born children who had percent predicted forced expiratory volume in 1 second (%FEV1) less than or equal to 85% compared with inhaled placebo treatment.

Design, Setting, and Participants

A double-blind, randomized, placebo-controlled trial was conducted to evaluate ICS and ICS/LABA against placebo. Preterm-born children (age, 7-12 years; gestation ≤34 weeks at birth) who did not have clinically significant congenital, cardiopulmonary, or neurodevelopmental abnormalities underwent spirometry, exercise testing, and measurement of fractional exhaled nitric oxide before and after treatment. A total of 144 preterm-born children at the Children's Hospital for Wales in Cardiff, UK, were identified and enrolled between July 1, 2017, and August 31, 2019.

Interventions

Each child was randomized to 1 of 3 cohorts: fluticasone propionate, 50 μg, with placebo; fluticasone propionate, 50 μg, with salmeterol, 25 μg; or placebo inhalers, all given as 2 puffs twice daily for 12 weeks. Children receiving preexisting ICS treatment underwent washout prior to randomization to ICS or ICS/LABA.

Main Outcomes and Measures

The primary outcome was between-group differences assessed by adjusted pretreatment and posttreatment differences of %FEV1 using analysis of covariance. Intention-to-treat analysis was conducted.

Results

Of 144 preterm-born children who were identified with %FEV1 less than or equal to 85%, 53 were randomized. Treatment allocation was 20 children receiving ICS (including 5 with prerandomization ICS), 19 children receiving ICS/LABA (including 4 with prerandomization ICS), and 14 children receiving placebo. The mean (SD) age of children was 10.8 (1.2) years, and 29 of the randomized children (55%) were female. The posttreatment %FEV1 was adjusted for sex, gestation, bronchopulmonary dysplasia, intrauterine growth restriction, pretreatment corticosteroid status, treatment group, and pretreatment values. Posttreatment adjusted means for %FEV1, using analysis of covariance, were 7.7% (95% CI, -0.27% to 15.72%; P = .16) higher in the ICS group and 14.1% (95% CI, 7.3% to 21.0%; P = .002) higher in the ICS/LABA group compared with the placebo group. Active treatment decreased the fractional exhaled nitric oxide and improved postexercise bronchodilator response but did not improve exercise capacity. One child developed cough when starting inhaler treatment; no other adverse events reported during the trial could be attributed to the inhaler treatment.

Conclusions and Relevance

The results of this randomized clinical trial suggest that combined ICS/LABA treatment is beneficial for prematurity-associated lung disease in children.

Trial Registration

EudraCT number: 2015-003712-20.

Gelsolin Attenuates Neonatal Hyperoxia-Induced Inflammatory Responses to Rhinovirus Infection and Preserves Alveolarization

Prematurity and bronchopulmonary dysplasia (BPD) increase the risk of asthma later in life. Supplemental oxygen therapy is a risk factor for chronic respiratory symptoms in infants with BPD. Hyperoxia induces cell injury and release of damage-associated molecular patterns (DAMPs). Cytoskeletal filamentous actin (F-actin) is a DAMP which binds Clec9a, a C-type lectin selectively expressed on CD103+ dendritic cells (DCs). Co-stimulation of Clec9a and TLR3 induces maximal proinflammatory responses. We have shown that neonatal hyperoxia (a model of BPD) increases lung IL-12+Clec9a+CD103+ DCs, pro-inflammatory responses and airway hyperreactivity following rhinovirus (RV) infection. CD103+ DCs and Clec9a are required for these responses. Hyperoxia increases F-actin levels in bronchoalveolar lavage fluid (BALF). We hypothesized that the F-actin severing protein gelsolin attenuates neonatal hyperoxia-induced Clec9a+CD103+ DC-dependent pro-inflammatory responses to RV and preserves alveolarization. We exposed neonatal mice to hyperoxia and treated them with gelsolin intranasally. Subsequently we inoculated the mice with RV intranasally. Alternatively, we inoculated normoxic neonatal mice with BALF from hyperoxia-exposed mice (hyperoxic BALF), RV and gelsolin. We analyzed lung gene expression two days after RV infection. For in vitro studies, lung CD11c+ cells were isolated from C57BL/6J or Clec9a^gfp-/- mice and incubated with hyperoxic BALF and RV. Cells were analyzed by flow cytometry. In neonatal mice, gelsolin blocked hyperoxia-induced Il12p40, TNF-α and IFN-γ mRNA and protein expression in response to RV infection. Similar effects were observed when gelsolin was co-administered with hyperoxic BALF and RV. Gelsolin decreased F-actin levels in hyperoxic BALF in vitro and inhibited hyperoxia-induced D103lo DC expansion and inflammation in vivo. Gelsolin also attenuated hyperoxia-induced hypoalveolarization. Further, incubation of lung CD11c+ cells from WT and Clec9a^gfp-/- mice with hyperoxic BALF and RV, showed Clec9a is required for maximal hyperoxic BALF and RV induced IL-12 expression in CD103+ DCs. Finally, in tracheal aspirates from mechanically ventilated human preterm infants the F-actin to gelsolin ratio positively correlates with FiO2, and gelsolin levels decrease during the first two weeks of mechanical ventilation. Collectively, our findings demonstrate a promising role for gelsolin, administered by inhalation into the airway to treat RV-induced exacerbations of BPD and prevent chronic lung disease.

Prematurity and Long-Term Respiratory Morbidity—What Is the Critical Gestational Age Threshold?

Respiratory morbidity is a hallmark complication of prematurity. Children born preterm are exposed to both short- and long-term respiratory morbidity. This study aimed to investigate whether a critical gestational age threshold exists for significant long-term respiratory morbidity. A 23-year, population-based cohort analysis was performed comparing singleton deliveries at a single tertiary medical center. A comparison of four gestational age groups was performed according to the WHO classification: term (≥37.0 weeks, reference group), moderate to late preterm (32.0–36.6 weeks), very preterm (28.0–31.6 weeks) and extremely preterm (24.0–27.6 weeks). Hospitalizations of the offspring up to the age of 18 years involving respiratory morbidities were evaluated. A Kaplan–Meier survival curve was used to compare cumulative hospitalization incidence between the groups. A Cox proportional hazards model was used to control for confounders and time to event. Overall, 220,563 singleton deliveries were included: 93.6% term deliveries, 6% moderate to late preterm, 0.4% very preterm and 0.1% extremely preterm. Hospitalizations involving respiratory morbidity were significantly higher in children born preterm (12.7% in extremely preterm children, 11.7% in very preterm, 7.0% in late preterm vs. 4.7% in term, p < 0.001). The Kaplan–Meier survival curve demonstrated a significantly higher cumulative incidence of respiratory-related hospitalizations in the preterm groups (log-rank, p < 0.001). In the Cox regression model, delivery before 32 weeks had twice the risk of long-term respiratory morbidity. Searching for a specific gestational age threshold, the slope for hospitalization rate was attenuated beyond 30 weeks’ gestation. In our population, it seems that 30 weeks’ gestation may be the critical threshold for long-term respiratory morbidity of the offspring, as the risk for long-term respiratory-related hospitalization seems to be attenuated beyond this point until term.

The epidemiology of apnoea of prematurity

WHAT IS KNOWN AND OBJECTIVE

Many premature infants less than 37 weeks gestational age (GA), and almost all infants less than 28 weeks GA, will experience apnoea of prematurity (AOP)-a cessation of respiration for 20 or more seconds (or less than 20 s if accompanied by other signs). Because the treatment options for AOP are so limited, we explore its epidemiology, with the ultimate hope of learning how to decrease its incidence.

COMMENT

Although AOP usually resolves with maturation of the respiratory system, many short- and long-term negative effects are correlated statistically with AOP (although direct causality has not been established). The primary risk factor for AOP is preterm birth, but delivery technique, genetics, socioeconomic status, racial disparities and other influences are suspected to be involved. Anaemia, asthma and gastric reflux have also been associated with preterm birth, but the relationship with AOP is unclear. The postulated associations and the strength of the evidence are briefly reviewed and discussed.

WHAT IS NEW AND CONCLUSION

Attempts to elucidate the epidemiology of apnoea of prematurity have been challenging. Studies of AOP are hampered in part by challenges in monitoring the condition, the interplay of multiple comorbidities in preterm neonates and lack of expert consensus definitions. However, since the primary risk factor is preterm birth, efforts to decrease the prevalence of preterm birth would have a positive secondary effect on the prevalence of AOP. Until then, better pharmacotherapeutic options are needed.

What is the impact of birth weight corrected for gestational age on later onset asthma: a meta-analysis

Background

Asthma is a common multifactorial disease affecting millions worldwide. The Barker hypothesis postulates an association between later onset disease risk and energy exposure in utero. Birth weight corrected for gestational age is better for measuring the infant size, which reflects energy exposure in utero. Findings on asthma and birth weight corrected for gestational age have been inconclusive. We conducted a meta-analysis to further clarify the relationship between birth weight corrected for gestational age and later onset asthma.

Methods

A systematic literature search of the PubMed, Web of Science, MEDLINE, and Scopus databases up to January 2021 was conducted. The subject terms were used as follows: “asthma”, “allerg*”, “respiratory”, “birth weight”, “gestational age”, “birth outcomes”, “intrauterine growth retardation”, and “fetal growth restriction”.

Results

We included 12 articles with data from a total of 6,713,596 people. Compared with non-SGA infants, infants small for gestation age (SGA) were not associated with an increased risk of asthma (OR = 1.07; 95% CI 0.94–1.21). However, in the subgroup analysis, we found an increased risk of later onset asthma among SGA in studies conducted in Asia, with a large sample size, and defined asthma through medical records rather than questionnaires. Large for gestational age (LGA) was not associated with an increased risk of asthma when non-LGA or appropriated for gestational age (AGA) infants were used as the reference (OR = 1.02; 95% CI 0.90–1.16; OR = 1.01; 95% CI 0.88–1.15).

Conclusion

These results indicated that neither SGA nor LGA was associated with an increased risk of asthma. However, considering the limitations of the research, these results should be interpreted with caution.

Outpatient Respiratory Management of Infants, Children, and Adolescents with Post-Prematurity Respiratory Disease: An Official American Thoracic Society Clinical Practice Guideline

Background: Premature birth affects millions of neonates each year, placing them at risk for respiratory disease due to prematurity. Bronchopulmonary dysplasia is the most common chronic lung disease of infancy, but recent data suggest that even premature infants who do not meet the strict definition of bronchopulmonary dysplasia can develop adverse pulmonary outcomes later in life. This post-prematurity respiratory disease (PPRD) manifests as chronic respiratory symptoms, including cough, recurrent wheezing, exercise limitation, and reduced pulmonary function. This document provides an evidence-based clinical practice guideline on the outpatient management of infants, children, and adolescents with PPRD. Methods: A multidisciplinary panel of experts posed questions regarding the outpatient management of PPRD. We conducted a systematic review of the relevant literature. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to rate the quality of evidence and the strength of the clinical recommendations. Results: The panel members considered the strength of each recommendation and evaluated the benefits and risks of applying the intervention. In formulating the recommendations, the panel considered patient and caregiver values, the cost of care, and feasibility. Recommendations were developed for or against three common medical therapies and four diagnostic evaluations in the context of the outpatient management of PPRD. Conclusions: The panel developed recommendations for the outpatient management of patients with PPRD on the basis of limited evidence and expert opinion. Important areas for future research were identified.

Motor outcomes of children born extremely preterm; from early childhood to adolescence

Children and adolescents born extremely preterm (EP; <28 weeks' gestation) are at greater risk of motor impairment, including cerebral palsy and developmental coordination disorder, than their term born peers. Importantly, motor impairment has implications beyond performing motor skills; it negatively affects outcomes as diverse as school success, emotional wellbeing, physical health, and physical activity (PA) participation. This review will outline what is known about PA participation across childhood and adolescence for children born EP and term, recognising that PA may improve physical, social, and mental health outcomes. Critically, PA participation occurs in the context of children's and adolescents' daily lives, and is influenced by the family, social and physical environment, as well as by the child's personal factors, such as motor impairment. Further research is needed to better understand PA participation levels and correlates for children and adolescents born preterm, to better inform effective and sustainable interventions.

Development and validation of a self-reported questionnaire to assess occupational balance in parents of preterm infants

Background

Parents’ meaningful activities (occupations) and occupational balance are relevant to neonatal care. Valid and reliable self-reported measurement instruments are needed to assess parents’ occupational balance and to evaluate occupational balance interventions in neonatal care. The aims of this study were to develop a self-reported questionnaire on occupational balance in informal caregivers (OBI-Care) and to examine its measurement properties including construct validity and internal consistency.

Methods and findings

A mixed method multicenter study design was employed. Items of the OBI-Care were created with parents of preterm infants based on qualitative research methods. Measurement properties were analyzed with quantitative data of parents of preterm infants. Construct validity was assessed by determining dimensionality, overall and item fit to a Rasch model, differential item functioning and threshold ordering. Internal consistency was examined by determining inter-item and item-total correlations, Cronbach’s alpha and Rasch’s person separation index. Fourteen parents participated in item creation. Measurement properties were explored in data of 304 parents. Twenty-two items, summarized in three subscales were compiled to the OBI-Care. Items showed an overall fit and except one item, an item fit to the Rasch model. There was no evidence of differential item functioning and all items displayed ordered thresholds. Each subscale had good values of person separation indices and Cronbach’s alpha.

Conclusions

The OBI-Care demonstrates construct validity and internal consistency and is thus a suitable measurement instrument to assess occupational balance of parents of preterm infants in neonatal care. OBI-Care is generic and can be applied in various health care settings.

Recommendations to optimize life-long health and wellbeing for people born preterm

The preterm birth rate in the United States is 10%, with 8% being born between 36 and 32 weeks of gestation, and the remaining 2% born less than 31 weeks of gestation. The global preterm birth rate varies from 5% to 18%, with varying survival rates. These percentages signify a population of people that will receive health care across the life course without ever being asked about a preterm birth history. With a steady rise in the survival rate of preterm infants being discharged home from the neonatal intensive care unit, with limited referrals for neonatal or developmental follow up, it is essential adult care providers ask the right questions and identify risk factors for this vulnerable population. This review describes the recently published, evidence-based recommendations for addressing preterm history across the life course. A robust review of the literature has demonstrated that the long-term sequelae of being born preterm can adversely affect health and quality of life. The following will offer preterm birth history recommendations based on assessment and diagnosis, prevention and management and referral and treatment. The goal of the recommendations is to create awareness among adult health providers in acknowledging a past medical history of preterm birth and providing appropriate preventive care, therefore shifting the paradigm of care from reactive intervention to proactive care.

Lung growth and pulmonary function after prematurity and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) still carries a heavy burden of morbidity and mortality in survivors of extreme prematurity. The disease is characterized by simplification of the alveolar structure, involving a smaller number of enlarged alveoli due to decreased septation and a dysmorphic pulmonary microvessel growth. These changes lead to persistent abnormalities mainly affecting the smaller airways, lung parenchyma, and pulmonary vasculature, which can be assessed with lung function tests and imaging techniques. Several longitudinal lung function studies have demonstrated that most preterm-born subjects with BPD embark on a low lung function trajectory, never achieving their full airway growth potential. They are consequently at higher risk of developing a chronic obstructive pulmonary disease-like phenotype later in life. Studies based on computer tomography and magnetic resonance imaging, have also shown that in these patients there is a persistence of lung abnormalities like emphysematous areas, bronchial wall thickening, interstitial opacities, and mosaic lung attenuation also in adult age. This review aims to outline the current knowledge of pulmonary and vascular growth in survivors of BPD and the evidence of their lung function and imaging up to adulthood.

Risk factors for recurrent wheezing in preterm infants who received prophylaxis with palivizumab

OBJECTIVE

To determine the prevalence of recurrent wheezing (RW) in preterm infants who received prophylaxis against severe infection with respiratory syncytial virus (RSV) and to identify genetic susceptibility (atopy or asthma) and risk factors for RW.

METHODS

This was a cross-sectional study involving preterm infants who received prophylaxis with palivizumab at a referral center in Brazil during the first two years of age. A structured questionnaire was administered in a face-to-face interview with parents or legal guardians.

RESULTS

The study included 410 preterm infants (median age = 9 months [0-24 months]). In the sample as a whole, 111 children (27.1%; [95% CI, 22.9-31.5]) had RW. The univariate analysis between the groups with and without RW showed no differences regarding the following variables: sex, ethnicity, maternal level of education, gestational age, birth weight, breastfeeding, number of children in the household, day care center attendance, pets in the household, and smoking caregiver. The prevalence of RW was twice as high among children with bronchopulmonary dysplasia (adjusted OR = 2.08; 95% CI, 1.11-3.89; p = 0.022) and almost five times as high among those with a personal/family history of atopy (adjusted OR = 4.96; 95% CI, 2.62-9.39; p < 0.001) as among those without these conditions.

CONCLUSIONS

Preterm infants who received prophylaxis with palivizumab but have a personal/family history of atopy or bronchopulmonary dysplasia are more likely to have RW than do those without these conditions.

Atopic diseases and airway-related symptoms in Bavarian pre-schoolers: determinants and association with immunization

BACKGROUND

Atopic diseases are among the most common chronic conditions in childhood. Causes of allergies are manifold. The aim of this paper is to evaluate risk factors for atopic diseases and unremitting wheeze and to examine if there is an association between measles, mumps and rubella (MMR) vaccination and atopic dermatitis, asthma and unremitting wheeze in Bavarian pre-schoolers.

METHODS

Parents filled out a questionnaire on children's health and environmental and socioeconomic factors. The questionnaire was administered within the Health Monitoring Units in a cross-sectional study in Bavaria, Germany (2014/2015). Data on vaccinations were obtained via the School Entrance Examination, a mandatory examination for pre-school children in Bavaria. Rates of influential factors of atopic diseases and wheeze, MMR and DTP (diphtheria, pertussis and tetanus) vaccination were calculated for all children stratified by health outcomes. To examine if there is an association between MMR vaccination and health outcomes, a multiple logistic regression analysis was performed.

RESULTS

Data were available for 3237 individuals. Symptoms and diseases were more frequent in boys. Higher parental education was associated with a higher prevalence of atopic dermatitis. There were no significant associations between any of the health outcome groups and MMR vaccination in the multiple logistic regression models with adjustment for potential confounders.

CONCLUSIONS

The present study is in line with the current state of research that MMR vaccination is not associated with atopic diseases.

Association of Early Life Factors with Prematurity-Associated Lung Disease: Prospective Cohort Study

Background

Although bronchopulmonary dysplasia (BPD) is associated with lung function deficits in childhood, many who develop BPD have normal lung function in childhood and many without BPD, including those born at 33–34 weeks of gestation, have lung dysfunction in childhood. Since the predictability of BPD for future lung deficits is increasingly doubted, we prospectively recruited preterm-born children to identify early-life factors associated with lung function deficits after preterm birth.

Methods

From 767 children aged 7–12 years who had their respiratory symptoms assessed, and had spirometry before and after a bronchodilator in our Respiratory Health Outcomes in Neonates (RHiNO) study, 739 (544 preterm-born at ≤34 weeks of gestation and 195 term-born) had satisfactory lung function. Data were analysed using multivariable logistic regression and mediation.

Results

When preterm-born children were classified according to their lung function, low lung function (prematurity-associated lung disease (PLD)) was associated with BPD, gestation and intra-uterine growth restriction (IUGR) on univariable logistic regression analyses. However, on multivariable logistic regression analyses, gestation (β= –0.153, se 0.051; p=0.003) and IUGR (OR 1.783, 95% CI 1.06–3.00; p=0.029) remained significantly associated with later deficits of lung function, but BPD (OR 0.99, 95% CI 0.52–1.89; p=0.974) did not. Mediation analyses confirmed these results.

Conclusions

Although traditionally BPD has been associated with low lung function in later life, the data show that gestation and IUGR are significantly associated with PLD in childhood, but BPD is not. By identifying children with PLD, we can better understand the underlying mechanisms and develop optimal therapies.

Although traditionally bronchopulmonary dysplasia is thought to be associated with longer term lung function deficits, this study shows that gestation and fetal growth restriction are better predictors of lung function deficits in prematurely born childrenhttps://bit.ly/3obSdSz

Intermittent Hypoxia-Hyperoxia and Oxidative Stress in Developing Human Airway Smooth Muscle

Premature infants are frequently and intermittently administered supplemental oxygen during hypoxic episodes, resulting in cycles of intermittent hypoxia and hyperoxia. The relatively hypoxic in utero environment is important for lung development while hyperoxia during the neonatal period is recognized as detrimental towards the development of diseases such as bronchopulmonary dysplasia and bronchial asthma. Understanding early mechanisms that link hypoxic, hyperoxic, and intermittent hypoxic-hyperoxic exposures to altered airway structure and function are key to developing advanced therapeutic approaches in the clinic. Changes in oxygen availability can be detrimental to cellular function and contribute to oxidative damage. Here, we sought to determine the effect of oxygen on mitochondria in human fetal airway smooth muscle cells exposed to either 5% O₂, 21% O₂, 40% O₂, or cycles of 5% and 40% O₂ (intermittent hypoxia-hyperoxia). Reactive oxygen species production, altered mitochondrial morphology, and changes in mitochondrial respiration were assessed in the context of the antioxidant N-acetylcysteine. Our findings show developing airway smooth muscle is differentially responsive to hypoxic, hyperoxic, or intermittent hypoxic-hyperoxic exposure in terms of mitochondrial structure and function. Cycling O₂ decreased mitochondrial branching and branch length similar to hypoxia and hyperoxia in the presence of antioxidants. Additionally, hypoxia decreased overall mitochondrial respiration while the addition of antioxidants increased respiration in normoxic and O₂-cycling conditions. These studies show the necessity of balancing oxidative damage and antioxidant defense systems in the developing airway.

Early Life Factors Associated with Preschool Wheezing in Preterm Infants

Advanced neonatal care has increased the survival of neonates born prematurely, and prematurity is a well-known risk factor for asthma/wheezing disorders. Thus, this prospective study aimed to determine the early life factors associated with preschool wheezing in premature neonates. Preterm neonates born between 2012 and 2017 were recruited, excluding those with bacterial infection within 7 days of life, maternal sepsis, and maternal chorioamnionitis. Birth and admission history, comorbidities, and maternal history were documented. Respiratory problems were followed-up at the neonatal outpatient department. Patients were divided into wheezing and non-wheezing groups. Data were analyzed using the Mann-Whitney test and Fisher's exact test, and multivariable logistic regression was used to define the risk factors of preschool wheezing/asthma. A total of 125 preterm infants were enrolled, including 19 in the wheezing group and 106 in the non-wheezing group. Patients in the wheezing group had longer duration of intubation (p = 0.025), higher rates for exclusive breast milk feeding (p = 0.012), and higher re-hospitalization rates for respiratory tract infections (p < 0.001), especially for respiratory syncytial virus (RSV) bronchiolitis (p = 0.045). The incidence of allergic rhinitis was also higher in the wheezing group (p = 0.005). After multivariable logistic regression, allergic rhinitis and re-hospitalization for respiratory tract infections were two significant risk factors for preschool wheezing/asthma in premature neonates. Close follow-up of premature infants at high risk for asthma susceptibility is recommended.

Disease modelling following organoid-based expansion of airway epithelial cells

Air-liquid interface (ALI) cultures are frequently used in lung research but require substantial cell numbers that cannot readily be obtained from patients. We explored whether organoid expansion (3D) can be used to establish ALI cultures from clinical samples with low epithelial cell numbers. Airway epithelial cells were obtained from tracheal aspirates (TA) from preterm newborns, and from bronchoalveolar lavage (BAL) or bronchial tissue (BT) from adults. TA and BAL cells were 3D-expanded, whereas cells from BT were expanded in 3D and 2D. Following expansion, cells were cultured at ALI to induce differentiation. The impact of cell origin and 2D or 3D expansion was assessed with respect to (i) cellular composition; (ii) response to cigarette smoke exposure; (iii) effect of Notch inhibition or IL-13 stimulation on cellular differentiation. We established well-differentiated ALI cultures from all samples. Cellular compositions (basal, ciliated and goblet cells) were comparable. All 3D-expanded cultures showed a similar stress response following cigarette smoke exposure but differed from the 2D-expanded cultures. Higher peak levels of antioxidant genes HMOX1 and NQO1 and a more rapid return to baseline, and a lower unfolded protein response was observed after cigarette smoke exposure in 3D-derived cultures compared to 2D-derived cultures. Additionally, TA- and BAL-derived cultures were less sensitive to modulation by DAPT or IL-13 than BT-derived cultures. Organoid-based expansion of clinical samples with low cell numbers, such as TA from preterm newborns is a valid method and tool to establish ALI cultures.

Low Dose Hyperoxia Primes Airways for Fibrosis in Mice after Influenza A Infection

It is well known that supplemental oxygen used to treat preterm infants in respiratory distress is associated with permanently disrupting lung development and the host response to influenza A virus (IAV). However, many infants who go home with normally functioning lungs are also at risk for hyperreactivity after a respiratory viral infection. We recently reported a new, low-dose hyperoxia mouse model (40% for 8 days; 40x8) that causes a transient change in lung function that resolves, rendering 40x8 adult animals functionally indistinguishable from room air controls. Here we reported that when infected with IAV, 40x8 mice display an early transient activation of TGFβ signaling and later airway hyperreactivity associated with peribronchial inflammation (profibrotic macrophages) and fibrosis compared to infected room air controls, suggesting neonatal oxygen induced hidden molecular changes that prime the lung for hyperreactive airways disease. While searching for potential activators of TGFβ signaling, we discovered that thrombospondin-1 (TSP-1) is elevated in naïve 40x8 mice compared to controls and localized to lung megakaryocytes and platelets before and during IAV infection. Elevated TSP-1 was also identified in human autopsy samples of former preterm infants with bronchopulmonary dysplasia. These findings reveal how low doses of oxygen that do not durably change lung function may prime it for hyperreactive airways disease by changing expression of genes, such as TSP-1, thus helping to explain why former preterm infants who have normal lung function are susceptible to airway obstruction and increased morbidity after viral infection.

Distinct lung function and bronchodilator responses between term and preterm young children with recurrent wheezing

BACKGROUND

Recurrent or unresolved wheezing is a common complaint in certain young children populations, especially those born preterm. Using infant lung function testing, we aimed to distinguish the differences between term and preterm young children with recurrent wheezing.

METHODS

Children under 2 years of corrected age were enrolled if they had 3 or more wheezing episodes during the enrollment period. Healthy term controls of comparable age were also recruited for reference. Measurements of lung function were made, including tidal breathing, passive respiratory mechanics, and forced tidal and raised-volume expiration. For children with recurrent wheezing, raised-volume forced expiration was repeated after an adequate delivery of bronchodilator nebulization was achieved.

RESULTS

In total, 68 young children (40 with recurrent wheezing and 28 healthy controls) were recruited. Among children with recurrent wheezing, 23 preterm children (preterm group), and 17 term children (term group) were enrolled. Compared with healthy controls, both the term and preterm groups had lower lung function as measured by absolute values and z scores. The term group performed worse than the preterm group with regard to forced vital capacity, forced expiratory volume at 0.5 s (FEV_0.5), and peak expiratory flow. Following bronchodilator nebulization, the term group had significantly higher increases in FEV_0.5 and forced mid-expiratory flow than the preterm group.

CONCLUSION

Young children with recurrent wheezing, especially term infants, demonstrated lower lung function than healthy controls. Moreover, the term group evidenced greater responsiveness to bronchodilators than the preterm group. The distinct bronchodilator responses may offer further information to guide the diagnosis and treatment of young children with recurrent wheezing.

CPAP protects against hyperoxia-induced increase in airway reactivity in neonatal mice

BACKGROUND

Oxygen and continuous positive airway pressure (CPAP) are primary modes of respiratory support for preterm infants. Animal models, however, have demonstrated adverse unintended effects of hyperoxia and CPAP on lung development. We investigate the effects of combined neonatal hyperoxia and CPAP exposure on airway function and morphology in mice.

METHODS

Newborn mice were exposed to hyperoxia (40% O₂) 24 h/day for 7 consecutive days with or without daily (3 h/day) concomitant CPAP. Two weeks after CPAP and/or hyperoxia treatment ended, lungs were assessed for airway (AW) hyperreactivity and morphology.

RESULTS

CPAP and hyperoxia exposure alone increased airway reactivity compared to untreated control mice. CPAP-induced airway hyperreactivity was associated with epithelial and smooth muscle proliferation. In contrast, combined CPAP and hyperoxia treatment no longer resulted in increased airway reactivity, which was associated with normalization of smooth muscle and epithelial proliferation to values similar to untreated mice.

CONCLUSIONS

Our data suggest that the combination of CPAP and hyperoxia decreases the adverse consequences on airway remodeling of either intervention alone. The complex interaction between mechanical stretch (via CPAP) and hyperoxia exposure on development of immature airways has implications for the pathophysiology of airway disease in former preterm infants receiving non-invasive respiratory support.

IMPACT

CPAP and mild hyperoxia exposure alone increase airway reactivity in the neonatal mouse model. In contrast, combined CPAP and hyperoxia no longer induce airway hyperreactivity. Combined CPAP and hyperoxia normalize smooth muscle and epithelial proliferation to control values. Interaction between CPAP-induced stretch and mild hyperoxia exposure on immature airways has important implications for airway pathophysiology in former preterm infants.

Factors associated with recurrent wheezing in the first year of life among premature newborns from Neonatal Intensive Care Units

Abstract Objectives: to determine the prevalence and factors associated with recurrent wheezing in the first year of life among premature newborns from Neonatal Intensive Care Units, in the city of Montes Claros, northern Minas Gerais. Methods: cross-sectional study, with data collection from medical records of a follow-up clinic, interviews with mothers and, eventually, search in hospital records. Bivariate analyzes were carried out between sociodemographic and clinical characteristics and recurrent wheezing. Variables associated up to the level of 20% were analyzed by binary logistic regression, and associations defined by the Odds Ratio and respective 95% confidence intervals. Only variables associated with a 5% significance level were maintained in the final model of logistic regression. Results: among 277 infants studied, about one fifth (21.3%) were extremely low birth weight preterm and more than half (60.7%) had birth weight below 1500 grams. The prevalence of recurrent wheezing was 14.4% (CI95% = 10.3-18.4). Mechanical ventilation (OR = 2.12; CI95% = 1.09-4.76; p = 0.030) and oxygen therapy time ≥ 15 days (OR = 2.49; CI95%= 1.12-5.00; p = 0.010) were the risk factors for the event. Conclusions: there is a high prevalence of recurrent wheezing in the evaluated group and the associated variables reiterate the risk of prolonged oxygen therapy and mechanical ventilation for premature newborns.

Childhood food insecurity and incident asthma: A population-based cohort study of children in Ontario, Canada

BACKGROUND

Childhood food insecurity has been associated with prevalent asthma in cross-sectional studies. Little is known about the relationship between food insecurity and incident asthma.

METHODS

We used administrative databases linked with the Canadian Community Health Survey, to conduct a retrospective cohort study of children <18 years in Ontario, Canada. Children without a previous diagnosis of asthma who had a household response to the Household Food Security Survey Module (HFSSM) were followed until March 31, 2018 for new asthma diagnoses using a validated administrative coding algorithm. We used multivariable Cox proportional hazard models to examine the association between food insecurity and incident asthma, and adjusted models sequentially for clinical and clinical/socioeconomic risk factors. As additional analyses, we examined associations by HFSSM respondent type, severity of food insecurity, and age of asthma diagnosis. Moreover, we assessed for interaction between food security and child's sex, household smoking status, and maternal asthma on the risk of incident asthma.

RESULTS

Among the 27,746 included children, 5.1% lived in food insecure households. Over a median of 8.34 years, the incidence of asthma was 7.33/1000 person-years (PY) among food insecure children and 5.91/1000 PY among food secure children (unadjusted hazard ratio [HR] 1.24, 95% CI 1.00 to 1.54, p = 0.051). In adjusted analyses associations were similar (HR 1.16, 95% CI 0.91 to 1.47, p = 0.24 adjusted for clinical risk factors, HR 1.24, 95% CI 0.97 to 1.60, p = 0.09 adjusted for clinical/socioeconomic factors). Associations did not qualitatively change by HFSSM respondent type, severity of food insecurity, and age of asthma diagnosis. There was no evidence of interaction in our models.

CONCLUSIONS

Food insecure children have numerous medical and social challenges. However, in this large population-based study, we did not observe that childhood food insecurity was associated with an increased risk of incident asthma when adjusted for important clinical and socioeconomic confounders.

Childhood Origins of Adult Lung Disease as Opportunities for Prevention

Prenatal and childhood exposures have been shown to impact lung development, lung function trajectory, and incidence and prevalence of respiratory disease. Early life may serve as a window of susceptibility to such exposures, with the potential to influence lifelong respiratory health. Risk factors encountered in early life with potentially durable impact on lung health include prematurity, respiratory viral illness, allergen sensitization and exposure, tobacco use and exposure, indoor and outdoor pollution, diet, and obesity. These exposures vary in the extent to which they are modifiable, and interventions aimed at reducing harmful exposures range from individual-level behavior modification to policy initiatives implemented to promote population health. For many exposures, including tobacco-related exposures, multilevel interventions are needed. Future research is needed to provide insight as to early-life interventions to promote optimal lung growth and prevent development of chronic respiratory disease. Clinicians should play an active role, assisting individual patients in avoiding known detrimental exposures including maternal smoking during pregnancy and initiation of active smoking. Clinicians can be empowered by evidence to support policies promoting reduction of population-level risk factors, such as restriction on electronic cigarette sales and legislation to uphold air quality standards, to encourage attainment of maximal lung function and reduce risk of chronic lung disease.

Predictors of home oxygen duration in chronic neonatal lung disease

AIMS

In infants with chronic neonatal lung disease (CNLD), we aimed to identify predictors of home oxygen duration, predictors of discharge oxygen flow rates, and the association of oxygen flow rates with respiratory outcomes.

METHODS

Infants with CNLD requiring home oxygen in 2016 and 2017 were retrospectively reviewed. Hazard ratios (HR) were estimated from Cox proportional hazards regression models in the cohort. A multinomial logistic regression model examined the effects of maternal and infant variables on discharge oxygen flow rates. Kruskal-Wallis test with univariate linear regression and Fisher's exact test with binomial univariate logistic regression were used to examine associations between oxygen flow groups and post-discharge clinical variables.

RESULTS

One hundred and forty-nine infants were included. Median corrected gestational age (CGA) at oxygen cessation was 6.8 months (interquartile range, 4.4) with 87.2% of infants weaned by 12 months CGA. Shorter initial neonatal intensive care unit (NICU) stay predicted faster oxygen weaning at 9 months (HR, 0.99; 95% confidence interval [CI], 0.98-1.00, p = .02) and 12 months (HR, 0.99; 95% CI, 0.98-1.00, p = .02). Infants with hypercarbia at discharge or discharged from NICU at higher CGA had higher odds of requiring ≥ 200 ml/min relative to ≤ 125 ml/min oxygen. Infants discharged with > 250 ml/min oxygen were more likely to have a respiratory-related admission before 2 years chronological age.

CONCLUSION

Shorter initial NICU stay was the best predictor of earlier home oxygen cessation. At NICU discharge, infants with hypercarbia or a higher CGA may require more home oxygen and experience more respiratory-related hospital admission in the first 2 years of chronological age.