Recurrent wheezing during the first 3 years of life in a birth cohort of moderate-to-late preterm infants

Growth and respiratory status at 3 years of age after moderate preterm, late preterm and early term births: the Japan Environment and Children's Study

OBJECTIVE

To assess the association between gestational age at birth and the risk of growth failure and respiratory symptoms at 3 years of age.

DESIGN

Cohort study using the Japan Environment and Children's Study database.

PATIENTS

A total of 86 158 singleton infants born without physical abnormalities at 32-41 weeks of gestation were enrolled between January 2011 and March 2014.

MAIN OUTCOME MEASURES

Growth failure (weight <10th percentile and height <10th percentile) and respiratory symptoms (asthma and wheezing) at 3 years of age.

METHODS

Logistic regression analysis was used to evaluate the risk of growth failure and respiratory symptoms in the moderately preterm, late preterm and early term groups compared with the full-term group after adjusting for socioeconomic and perinatal factors. Multiple imputation was used to reduce the attrition bias related to missing data.

RESULTS

The respective adjusted ORs (95% CI) of growth failure and respiratory symptoms for the moderate preterm, late preterm and early term groups compared with the full-term group were as follows: weight <10th percentile, 2.29 (1.48-3.54), 1.43 (1.24-1.71) and 1.20 (1.12-1.28); height <10th percentile, 2.34 (1.59-3.45), 1.42 (1.25-1.60) and 1.15 (1.09-1.22); asthma, 1.63 (1.06-2.50), 1.21 (1.04-1.41) and 1.16 (1.09-1.23); and wheezing, 1.39 (1.02-1.90), 1.37 (1.25-1.51) and 1.11 (1.06-1.17).

CONCLUSION

Moderate preterm, late preterm and early term births were associated with a higher risk of growth failure and respiratory symptoms at 3 years of age than full-term births, with an inverse dose-response pattern.

Predictors of recurrent wheezing in late preterm infants

INTRODUCTION

Premature infants have an increased risk of respiratory morbidity, including the development of recurrent wheezing. We sought to determine perinatal factors in late preterm infants associated with an increased risk of recurrent wheezing in the first 3 years of life.

METHODS

A retrospective chart review of infants born between 32 and 36 weeks gestational age at a tertiary hospital from 2013 to 2016 was performed. Infants with any co-morbid medical conditions were excluded. Recurrent wheezing was identified by two or more visit diagnoses for reactive airway disease, wheezing-associated respiratory infection, wheezing, or asthma during the first 3 years of life. Those with recurrent wheezing were compared to matched preterm infants who did not develop wheezing.

RESULTS

Three hundred and fourteen late preterm infants were included in this study; 210 infants developed recurrent wheezing while 104 did not. Gender, sex, and race were comparable between both groups. Development of wheezing was associated with positive family history of asthma (p = .014), receiving antibiotics during the neonatal period (p < .001), requiring continuous positive airway pressure for <24 h (p = .019), and receiving supplemental oxygen during the newborn period (p = .023).

CONCLUSION

This study retrospectively identified risk factors associated with development of wheezing in late preterm infants. Prospective studies are needed to determine whether these factors will predict recurrent wheeze in this patient population.

Are Babies Born Preterm High-Risk Asthma Candidates?

Among preterm infants, the risk of developing asthma is a matter of debate. This review discusses the state of the art of poorly understood prematurity-associated asthma. Impaired pulmonary function is common in children born prematurely. Preterm infants are prone to developing viral respiratory tract infections, bronchiolitis in the first year of life, and recurrent viral wheezing in preschool age. All of these conditions may precede asthma development. We also discuss the role of both atopic sensitization and intestinal microbiome and, consequently, immune maturation. Diet and pollution have been considered to better understand how prematurity could be associated with asthma. Understanding the effect of factors involved in asthma onset may pave the way to improve the prediction of this asthma phenotype.

An analysis of risk factors associated with recurrent wheezing in the pediatric population

BACKGROUND

Recurrent wheezing is a common clinical problem in early childhood, which is associated with significant morbidity. There is no international consensus on the management and prevention of recurrent wheezing; therefore, identifying the risk factors associated with recurrent wheezing is crucial to prevent episodes of wheezing in young children.

METHODS

In this retrospective study, we collected the data of 24,737 patients who were admitted to our hospital between 27th April 2012 and 11th September 2019. After screening for patients with wheezing, we identified 8572 patients with a primary diagnosis of pneumonia with wheezing. Patients' clinical data were collected from the hospital medical records. Patients were stratified for age in the groups of < 6 months, 6-12 months, and > 12 months.

RESULTS

Among the 8569 pediatric pneumonia patients with wheezing, there were 343 patients with recurrent wheezing. Most enrolled patients were under 6 months of age (45.17%) and had a normal birth weight (86.95%). Winter was the most common onset season for the first episode of wheezing, while spring was the most common season for the second episode of wheezing for those with recurrent wheezing. The univariate and multivariate logistic regression analysis for the risk factor associated with recurrent wheezing showed that male gender, past history of respiratory and cardiovascular diseases, low birth weight, development of severe pneumonia, and PICU admission were significantly associated with recurrent wheezing.

CONCLUSION

Male gender, past history of respiratory and cardiovascular diseases, low birth weight, severe pneumonia, and PICU admission are independent risk factors of recurrent wheezing in the pediatric population.

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.

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.

Lung mechanics and respiratory morbidities in school-age children born moderate-to-late preterm

BACKGROUND

Late and moderate prematurity may have an impact on pulmonary function during childhood. The present study aimed to investigate lung mechanics in school-age children born moderate-to-late preterm (MLPT).

METHODS

Children aged 5-10 years were enrolled in this case-control study. Lung function and bronchodilator response were assessed by impulse oscillometry (IOS) at two hospital-based specialized clinics. A structured questionnaire was employed to assess respiratory morbidities.

RESULTS

A total of 123 children was divided into two groups: case (MLPT) n = 52 and control (children born at term) n = 71. The results showed no difference between groups in mean baseline IOS variables: R5 0.80 ± 0.20 vs 0.82 ± 0.22 kPa/L/s, p = 0.594, R20 0.54 ± 0.13 vs 0.55 ± 0.13 kPa/L/s, p = 0.732, R5-R20 0.26 ± 0.12 vs 0.27 ± 0.15 kPa/L/s, p = 0.615, X5 -0.29 ± 0.01 vs -0.29 ± 0.1 kPa/L/s, p = 0.990, Fres 21.1 ± 3.3 vs 21.7 ± 3.1 L/s, p = 0.380, and AX 2.7 ± 3.36 vs 2.5 ± 1.31 kPa/L/s, p = 0.626. Bronchodilator response and the occurrence of respiratory morbidities after birth were also similar between groups.

CONCLUSIONS

This study found lung mechanics parameters to be similar in school-age children born MLPT and those born at term, suggesting that pulmonary plasticity continues to occur in children up to school age.

IMPACT

Late and moderate prematurity is associated with an increased risk of reduced pulmonary function during childhood. Follow-up reports in adolescents and adults born MLPT are scarce but have indicated pulmonary plasticity with normalization of airway function. Our results show that the lung function in school-age children born MLPT is similar to that of children born at term.

Development of Lung Function in Preterm Infants During the First Two Years of Life

INTRODUCTION

It remains unclear if prematurity itself can influence post delivery lung development and particularly, the bronchial size.

AIM

To assess lung function during the first two years of life in healthy preterm infants and compare the measurements to those obtained in healthy term infants during the same time period.

METHODS

This observational longitudinal study assessed lung function in 74 preterm (30+0 to 35+6 weeks' gestational age) and 76 healthy term control infants who were recruited between 2011 and 2013. Measurements of tidal breathing, passive respiratory mechanics, tidal and raised volume forced expirations (V'maxFRC and FEF_25-75, respectively) were undertaken following administration of oral chloral hydrate sedation according to ATS/ERS recommendations at 6- and 18-months corrected age.

RESULTS

Lung function measurements were obtained from the preterm infants and full term controls initially at 6 months of age. Preterm infants had lower absolute and adjusted values (for gestational age, postnatal age, sex, body size, and confounding factors) for respiratory compliance and V'maxFRC. At 18 months corrected postnatal age, similar measurements were repeated in 57 preterm infants and 61 term controls. A catch-up in tidal volume, respiratory mechanics parameters, FEV_0.5 and forced expiratory flows was seen in preterm infants.

CONCLUSION

When compared with term controls, the lower forced expiratory flows observed in the healthy preterm group at 6 months was no longer evident at 18 months corrected age, suggesting a catch-up growth of airway function.

Associations of early-life factors and indoor environmental exposure with asthma among children: a case-control study in Chongqing, China

BACKGROUND

Childhood asthma has substantial effects on children's health. It is important to identify influencing factors in early life in the development of childhood asthma. We aim to evaluate the effects of early-life factors and indoor environmental exposure on childhood asthma in Chongqing, China.

METHOD

We designed a case-control study to enrol children with asthma aged 3 to < 14 years old and controls in Chongqing, China. The "Children's Early Life and Indoor Environment Survey" was used to collect the early-life factors and indoor environmental exposure of foetuses in utero and of infants during the first 3 years of life. A multivariate logistic regression model was used to evaluate the association between independent variables and childhood asthma and the interaction of early-life factors and environmental exposure.

RESULTS

A total of 160 asthma cases and 247 controls were included in this study. The mean ages of the cases and controls were 5.53 ± 1.88 and 5.72 ± 2.34 years, respectively (P = 0.192). Early-life factors and indoor environmental exposure were independently associated with childhood asthma. Infectious diseases of the respiratory system in children under 3 years old [adjusted odds ratio (OR) = 5.76, 95% confidence interval (CI) 2.49-13.30], bedroom air conditioner use (adjusted OR = 4.61, 95% CI 1.45-14.64), and bedroom dampness/mould (adjusted OR = 2.98, 95% CI 1.54-5.75) ranked as the three most significant exposures associated with the risk of childhood asthma. Other factors associated with an increased risk of childhood asthma included second-hand smoke exposure in early life (adjusted OR = 1.93, 95% CI 1.24-3.00), neonatal pneumonia (adjusted OR = 1.90, 95% CI 1.05-3.42) and maternal allergic diseases during pregnancy (adjusted OR = 2.13, 95% CI 1.10-4.10). The interaction effects of child second-hand smoke exposure with other covariates were not found to be statistically significant.

CONCLUSIONS

Early-life factors and indoor environmental exposure are closely related to childhood asthma in Chongqing, China. Further interventions and management in the early life of children should be considered to prevent and control childhood asthma in Chongqing and similar cities.

Wheezing in preterm infants and children

Wheezing is a common outcome of preterm birth. This article will review the mechanisms, epidemiology, and treatment of wheezing in preterm children with and without a history of bronchopulmonary dysplasia.

Respiratory syncytial virus prophylaxis for prevention of recurrent childhood wheeze and asthma: a systematic review

BACKGROUND

Acute bronchiolitis caused by respiratory syncytial virus (RSV) has been associated with greater risk of recurrent wheezing and asthma. However, it is unclear whether this association is causal. RSV-specific monoclonal antibodies have been shown to reduce RSV-related hospitalisations in high-risk infants, but the longer-term follow-up has given conflicting evidence for prevention of recurrent wheeze or asthma.

OBJECTIVE

We performed a systematic review and meta-analysis to determine whether monoclonal antibody prophylaxis against RSV bronchiolitis reduces the risk of subsequent recurrent wheeze or asthma. If so, this may support the hypothesis of causality.

METHODS

Studies were identified via an online database search using Embase, MEDLINE, PubMed, Web of Science and the Cochrane Library. Manufacturers of monoclonal antibodies were contacted directly for unpublished data. The intervention of interest was RSV monoclonal antibody prophylaxis, and the primary outcome measure was recurrent wheeze and/or asthma. Studies were screened according to inclusion/exclusion criteria. Included studies were evaluated for quality and assessed for bias independently by 3 reviewers using the 'Grading of Recommendations Assessment, Development and Evaluation' (GRADE) approach. Results were extracted into 2 × 2 outcome tables and a meta-analysis carried out producing forest plots based on relative risk. Heterogeneity was assessed using the I2 statistic.

RESULTS

The search identified 141 articles, which, after screening, resulted in eight studies (2 randomised controlled trials), thus including 11,195 infants in the meta-analysis. The overall result demonstrated a non-statistically significant reduction in relative risk of developing recurrent wheeze or asthma (RR 0.60; 95% CI 0.31 to 1.16). Study quality was generally low with evidence of publication bias and statistical heterogeneity. However, sub-group analysis excluding studies deemed to be 'very low' quality showed a relative risk of 0.42 (95% CI 0.22 to 0.80, p = 0.008). A further sub-group analysis for infants aged 32 to < 36 weeks showed a statistically significant relative risk of 0.35 (95% CI 0.14 to 0.86, p = 0.02).

DISCUSSION

We did not identify an overall statistically significant benefit. However, our two sub-group analyses did find statistically significant benefits of monoclonal antibody therapy on the risk of recurrent wheeze and asthma. The main limitation of this study is the lack of high-quality randomised controlled trials, highlighting the need for more research in this field.