Airway obstruction in young adults born extremely preterm or extremely low birth weight in the postsurfactant era

Changes in Lung Function Among Infants Born Extremely Preterm over a 20-Year Period in the Post-Surfactant Era: A Retrospective Study

Lung function was assessed at 8 years in 308 infants born extremely preterm between 1994 and 2013. Although lung function of those infants born at 22 through 25 weeks remained unchanged, those who were born at 26-27 weeks showed a significant improvement over the past 2 decades.

Unravelling the respiratory health path across the lifespan for survivors of preterm birth

Many survivors of preterm birth will have abnormal lung development, reduced peak lung function and, potentially, an increased rate of physiological lung function decline, each of which places them at increased risk of chronic obstructive pulmonary disease across the lifespan. Current rates of preterm birth indicate that by the year 2040, around 50 years since the introduction of surfactant therapy, more than 700 million individuals will have been born prematurely-a number that will continue to increase by about 15 million annually. In this Personal View, we describe current understanding of the impact of preterm birth on lung function through the life course, with the aim of putting this emerging health crisis on the radar for the respiratory community. We detail the potential underlying mechanisms of prematurity-associated lung disease and review current approaches to prevention and management. Furthermore, we propose a novel way of considering lung disease after preterm birth, using a multidimensional model to determine individual phenotypes of lung disease-a first step towards optimising management approaches for prematurity-associated lung disease.

Transition to Adulthood for Extremely Preterm Survivors

OBJECTIVE

To compare transition into adulthood of survivors born extremely preterm (EP; <28 weeks' gestation) or extremely low birth weight (ELBW; <1000 g) in the postsurfactant era with term-born controls.

METHODS

Prospective longitudinal cohort study of all EP/ELBW survivors born in the State of Victoria, Australia between January 1, 1991 and December 31, 1992 and matched term-born controls. Outcomes include educational attainment, employment, financial status, romantic partnering, living arrangements, parenthood, physical health and mental health, risk-taking behaviors, life satisfaction, and interpersonal relationships at 25 years.

RESULTS

Data were available from 165 EP/ELBW and 127 control participants. Overall, there was little evidence for differences between the EP/ELBW and control groups on most comparisons after adjustment for social risk and multiple births. However, compared with controls, the EP/ELBW group was more likely to have their main source of income from government (adjusted odds ratio [aOR] 2.49, 95% confidence interval [CI] 1.21-5.13; P = .01) and to have never moved out of the parental home (aOR 2.13, 95% CI 1.27-3.58; P = .01), and fewer had ever engaged in smoking (aOR 0.52, 95% CI 0.28-0.98; P = .04), binge drinking (aOR 0.41, 95% CI 0.18-0.93; P = .03), or street drugs (aOR 0.56, 95% CI 0.32-0.98; P = .04).

CONCLUSIONS

Aside from clinically important differences in main income source, leaving the parental home, and reduced risk-taking behavior, survivors born EP/ELBW in the era since surfactant was introduced are transitioning into adulthood similarly to term-born controls in some areas assessed but not all.

Respiratory management and outcomes in high-risk preterm infants with development of a population outcome dashboard

INTRODUCTION

Bronchopulmonary dysplasia (BPD) is associated with adverse long-term respiratory and neurodevelopmental outcomes. No recent studies examined the changing respiratory management and outcomes, particularly severe BPD, across a whole population.

PURPOSE

Evaluate the temporal trends in the respiratory management and outcomes of preterm infants born below 32 weeks gestational age and develop an individualised dashboard of the incidence of neonatal outcome.

METHODS

Using the National Neonatal Research Database, we determined changes in respiratory management, BPD rates, postdischarge respiratory support and mortality in 83 463 preterm infants in England and Wales from 2010 to 2020.

RESULTS

Between 2010 and 2020, antenatal corticosteroids use increased (88%-93%, p<0.0001) and neonatal surfactant use decreased (65%-60%, p<0.0001). Postnatal corticosteroid use increased, especially dexamethasone (4%-6%, p<0.0001). More recently, hydrocortisone and budesonide use increased from 2% in 2017 to 4% and 3%, respectively, in 2020 (p<0.0001). Over the study period, mortality decreased (10.1%-8.5%), with increases in BPD (28%-33%), severe BPD (12%-17%), composite BPD/death (35%-39%) and composite severe BPD/death (21%-24%) (all p<0.0001). Overall, 11 684 infants required postdischarge respiratory support, increasing from 13% to 17% (p<0.0001), with 1843 infants requiring respiratory pressure support at discharge. A population dashboard (https://premoutcome.github.io/) depicting the incidence of mortality and respiratory outcomes, based on gestation, sex and birthweight centile, was developed.

CONCLUSION

More preterm infants are surviving with worse respiratory outcomes, particularly severe BPD requiring postdischarge respiratory support. Ultimately, these survivors will develop chronic respiratory diseases requiring greater healthcare resources.

Evidence of abnormality in glutathione metabolism in the airways of preterm born children with a history of bronchopulmonary dysplasia

Preterm-born children are at risk of long-term pulmonary deficits, including those who developed bronchopulmonary dysplasia (BPD) in infancy, however the underlying mechanisms remain poorly understood. We characterised the exhaled breath condensate (EBC) metabolome from preterm-born children, both with and without BPD. Following spirometry, EBC from children aged 7-12 years, from the Respiratory Health Outcomes in Neonates study, were analysed using Time-of-Flight Mass Spectrometry. Metabolite Set Enrichment Analysis (MSEA) linked significantly altered metabolites to biological processes. Linear regression models examined relationships between metabolites of interest and participant demographics. EBC was analysed from 214 children, 144 were born preterm, including 34 with BPD. 235 metabolites were detected, with 38 above the detection limit in every sample. Alanine and pyroglutamic acid were significantly reduced in the BPD group when compared to preterm controls. MSEA demonstrated a reduction in glutathione metabolism. Reduced quantities of alanine, ornithine and urea in the BPD group were linked with alteration of the urea cycle. Linear regression revealed significant associations with BPD when other characteristics were considered, but not with current lung function parameters. In this exploratory study of the airway metabolome, preterm-born children with a history of BPD had changes consistent with reduced antioxidant mechanisms suggesting oxidative stress.

Pulmonary phenotypes of bronchopulmonary dysplasia in the preterm infant

Bronchopulmonary dysplasia (BPD) remains the most common complication of premature birth, imposing a significant and potentially life-long burden on patients and their families. Despite advances in our understanding of the mechanisms that contribute to patterns of lung injury and dysfunctional repair, current therapeutic strategies remain non-specific with limited success. Contemporary definitions of BPD continue to rely on clinician prescribed respiratory support requirements at specific time points. While these criteria may be helpful in broadly identifying infants at higher risk of adverse outcomes, they do not offer any precise information regarding the degree to which each compartment of the lung is affected. In this review we will outline the different pulmonary phenotypes of BPD and discuss important features in the pathogenesis, clinical presentation, and management of these frequently overlapping scenarios.

Impact of postnatal dexamethasone timing on preterm mortality and bronchopulmonary dysplasia: a propensity score analysis

BACKGROUND

Postnatal dexamethasone (PND) is used in high-risk preterm infants after the first week of life to facilitate extubation and prevent bronchopulmonary dysplasia (BPD) but the optimal treatment timing remains unclear. Our objective was to explore the association between the timing of PND commencement and mortality and respiratory outcomes.

METHODS

This was a retrospective National Neonatal Research Database study of 84 440 premature infants born <32 weeks gestational age from 2010 to 2020 in England and Wales. Propensity score weighting analysis was used to explore the impact of PND commenced at three time-points (2-3 weeks (PND2/3), 4-5 weeks (PND4/5) and after 5 weeks (PND6+) chronological age) on the primary composite outcome of death before neonatal discharge and/or severe BPD (defined as respiratory pressure support at 36 weeks) alongside other secondary respiratory outcomes.

RESULTS

3469 infants received PND. Compared with PND2/3, infants receiving PND6+ were more likely to die and/or develop severe BPD (OR 1.68, 95% CI 1.28-2.21), extubate at later postmenstrual age (mean difference 3.1 weeks, 95% CI 2.9-3.4 weeks), potentially require respiratory support at discharge (OR 1.34, 95% CI 1.06-1.70) but had lower mortality before discharge (OR 0.38, 95% CI 0.29-0.51). PND4/5 was not associated with severe BPD or discharge respiratory support.

CONCLUSIONS

PND treatment after 5 weeks of age was associated with worse respiratory outcomes although residual bias cannot be excluded. A definitive clinical trial to determine the optimal PND treatment window, based on early objective measures to identify high-risk infants, is needed.

An Update on Lung Function of Extremely and Very Preterm Infants in Later Life: The Role of Early Nutritional Interventions

Birth occurring at ≤32 weeks' gestation ("very preterm") or at ≤28 weeks' gestation ("extremely preterm") potentially poses considerable health problems for the neonate, including respiratory sequelae, not only during the immediate newborn period, but throughout childhood and into adulthood. With the progressive improvements in neonatal care, the survival of extremely preterm and very preterm neonates has improved substantially. However, a considerable percentage of these infants suffer dysfunctions that may trigger, at some stage later in life, the onset of respiratory morbidities. The interruption of the normal development of the respiratory tract caused by preterm birth, in combination with postnatal lung injury caused by various interventions, e.g., mechanical ventilation and oxygen therapy, increases the risk ofthe development of long-term respiratory deficits in survivors. Those infants that are most affected are those who develop chronic lung disease of prematurity (also called bronchopulmonary dysplasia, BPD), but impaired lung function can develop irrespective of BPD diagnosis. Apart from indicating abnormal lung function in survivors of extreme prematurity, recent long-term follow-up studies also emphasize the crucial role of early nutritional intake as an effective strategy, which promotes lung growth and repair. This article will update the associations between extremely/very preterm birth with long-term respiratory outcomes. It will also discuss the protective effect of nutritional interventions, focusing on recently published follow-up data.

Risk of asthma in preterm infants with bronchopulmonary dysplasia: a systematic review and meta-analysis

BACKGROUND

This study aimed to systematically review and meta-analyze the available literature on the association between preterm infant bronchopulmonary dysplasia (BPD) and pre-adulthood asthma.

METHODS

Studies examining the association between BPD and asthma in children and adolescents were systematically reviewed, and a meta-analysis was conducted. We searched Scopus, Embase, Web of Science, PubMed, and Cochrane Library from the database inception to March 26, 2022. The pooled odds ratio (OR) estimate was used in our meta-analysis to calculate the correlation between BPD and the probability of developing asthma before adulthood. Stata 12.0 was used to conduct the statistical analysis.

RESULTS

The correlation between asthma and BPD in preterm newborns was examined in nine studies. We used a random effect model to pool the OR estimate. Our results indicated a marked increase in the risk of subsequent asthma in preterm infants with BPD [OR = 1.73, 95% confidence interval (CI) = 1.43-2.09]. Moreover, there was no obvious heterogeneity across the studies (P = 0.617, I2 = 0%). The pooled OR remained stable and ranged from 1.65 (95% CI = 1.35-2.01) to 1.78 (95% CI = 1.43-2.21). Regarding publication bias, the funnel plot for asthma risk did not reveal any noticeable asymmetry. We further performed Begg's and Egger's tests to quantitatively evaluate publication bias. There was no evidence of a publication bias for asthma risk (P > |Z| = 0.602 for Begg's test, and P > |t| = 0.991 for Egger's test).

CONCLUSIONS

Our findings indicate that preterm infants with BPD have a much higher risk of developing asthma in the future (OR = 1.73, 95% CI = 1.43-2.09). Preterm infants with BPD may benefit from long-term follow-up.

Modulation of pulmonary desmosomes by inhaler therapy in preterm-born children with bronchopulmonary dysplasia

Despite evidence demonstrating persistent lung function deficits in preterm-born children, especially in those who had bronchopulmonary dysplasia (BPD) in infancy, the underlying biological mechanisms explaining these lung function deficits remain poorly understood. We characterised the exhaled breath condensate (EBC) proteome in preterm-born children, with and without BPD; and before and after inhaler treatment. EBC from children aged 7-12 years, from the Respiratory Health Outcomes in Neonates (RHiNO) study, were analysed by Nano-LC Mass Spectrometry with Tandem Mass Tag labelling. Children with percent predicted forced expiratory volume in 1 second ≤ 85% were enrolled to a 12-week blinded randomised trial of inhaled corticosteroids alone (ICS) or with long-acting β₂-agonist (ICS/LABA) or placebo. EBC was analysed from 218 children at baseline, and 46 children received randomised inhaled therapy. 210 proteins were detected in total. For the 19 proteins present in every sample, the desmosome proteins: desmoglein-1, desmocollin-1 and plakoglobin were significantly decreased, and cytokeratin-6A was increased in preterm-born children with BPD when compared to preterm- and term-born controls. ICS/LABA treatment significantly increased abundance of desmoglein-1, desmocollin-1 and plakoglobin in the BPD group with low lung function, and significantly increased plakoglobin in those without BPD. No differences were noted after ICS treatment. Exploratory analyses of proteins not detected in all samples suggested decreased abundance of several antiproteases. This study provides proteomic evidence of ongoing pulmonary structural changes with decreased desmosomes in school-aged preterm-born children with BPD and low lung function, which was reversed with combined inhaled corticosteroids and long-acting β₂-agonists therapy.

Neonatal respiratory support related to lung function abnormalities in school-age children with bronchopulmonary dysplasia

OBJECTIVE

To elucidate the relationship between abnormal lung function (LF) at school age and neonatal respiratory support in very low birth weight children with bronchopulmonary dysplasia (BPD).

STUDY DESIGN

We retrospectively examined 78 BPD children whose LF was evaluated at 8-9 years. LF abnormalities were defined by reduced values of spirometric parameters. Adjusted odds ratios (aORs) for abnormal LF by the type and postmenstrual age (PMA) of respiratory support were calculated using logistic regression analysis after controlling perinatal factors.

RESULTS

Overall, 24 (31%) patients had LF abnormalities. Antenatal steroid use was associated with a decreased risk of abnormal LF [aOR, 0.31; 95% CI, 0.09-0.92]. Requiring positive-pressure support at 37 weeks' PMA correlated with abnormal LF [aOR, 4.58; 95% CI, 1.15-21.90]; whereas only low-flow oxygen at any PMA did not.

CONCLUSION

Requiring positive-pressure support at 37 weeks' PMA could be an indicator of abnormal LF at school age.

Lung Function of Preterm Children Parsed by a Polygenic Risk Score for Adult COPD

BACKGROUND: Chronic obstructive pulmonary disease (COPD) in adults is a result of environmental risk factors and genetic factors. Polygenic COPD risk scores are highly predictive for lung function in adults. We hypothesized that a polygenic COPD risk score is also predictive for lung function in children who are born preterm. METHODS: Infants with a birth weight of less than 1500 g (n=17,394) were enrolled in the German Neonatal Network. Among these children, we included those with chip genotyping and 5-year follow-up assessment (n=1957) in this analysis. A polygenic COPD risk score derived in adults with COPD was calculated on the basis of 1,637,882 single-nucleotide polymorphisms associated with forced expiratory volume within 1 second (FEV1) and 1,179,331 single-nucleotide polymorphisms associated with FEV1/FVC (forced vital capacity). This score was related to FEV1, FVC, and FEV1/FVC z scores by linear regression analysis. RESULTS: At a mean age at follow-up of 5.8±0.4 years, the polygenic COPD risk score was strongly associated with FEV1 (−0.05 z score/decile, P=6.5 × 10−9) and FEV1/FVC (−0.07 z score/decile, P=4.4 × 10−11) but not FVC. Children in the 10th decile of the polygenic COPD risk score — that is, those at the highest risk — had a mean FEV1 z score of −1.74 (±1.1), indicating lower lung function by these measures and higher rates of obstructive bronchitis. CONCLUSIONS: The upper deciles of a polygenic COPD risk score derived in adults identified a subgroup of children who were born preterm and who are at high risk for obstructive pulmonary disease of prematurity. This finding supports the notion that COPD-associated genes strongly impact lung function in premature children. (Funded by the German Federal Ministry of Education and Research.)

Influence of bronchopulmonary dysplasia on lung function in adolescents who were born extremely prematurely

OBJECTIVES

To assess if a previous diagnosis of bronchopulmonary dysplasia (BPD) was associated with poorer lung function at 16 to 19 years of age, regardless of whether postnatal corticosteroids had been administered.

WORKING HYPOTHESIS

Infants with BPD will have poorer lung function at 16 to 19 years of age.

STUDY DESIGN

Prospective follow-up study.

PATIENT-SUBJECT SELECTION

One hundred and sixty-one participants aged between 16 and 19 years who were born at less than 29 weeks of gestation; 87 had had BPD.

METHODOLOGY

Lung function was assessed by spirometry (FEV₁ , FVC, FEV₁ /FVC, FEF₇₅ , FEF₅₀ , FEF₂₅ , FEF_{25 -75} , PEF), impulse oscillometry (R5Hz and R20Hz), plethysmography (FRC_pleth , TLC_pleth , RV_pleth ), diffusion capacity of the lungs for carbon monoxide (D_L CO, D_L CO/VA) and lung clearance index (LCI). Questionnaires were used to quantify respiratory symptoms and a shuttle sprint test to assess exercise capacity.

RESULTS

At 16 to 19 years, those who had had a diagnosis of BPD had poorer airway function (FEV₁ , FEF₇₅ , FEF₅₀ , FEF_{25 -75} ) compared to those without. FVC and D_L CO were also poorer in those who had BPD. Those differences remained significant after adjusting for sex, gestational age, and maternal smoking. When excluding those who had received postnatal corticosteroids, differences remained significant in FEV₁ , FVC, and FEF₇₅ . There were no significant differences in exercise capacity or respiratory symptoms between those with and without BPD.

CONCLUSIONS

In adolescents and young adults born prematurely, those who had BPD had poorer lung function compared to those without, regardless of whether they had received postnatal corticosteroids.

Cardiopulmonary Function Abnormalities in Cohort of Adults following Bronchopulmonary Dysplasia as Preterm Infants

OBJECTIVE

This study was aimed to describe the cardiopulmonary profiles of adult patients with bronchopulmonary dysplasia (BPD), comparing them to normative adult values.

STUDY DESIGN

This study presents a retrospective chart review of all BPD patients followed in the adult BPD clinic, identified from institutional and archive databases, born preterm at ≤33 weeks of estimated gestational age (EGA) between January 1980 and December 2000.

RESULTS

Forty-four patients with BPD (26.4 ± 2.7 weeks of EGA) were included. Average age at follow-up was 19 years. Majority (61.4%) of the patients had a diagnosis of asthma. Mean spirometry values were: first second of forced expiration (FEV1) 74.1%, forced vital capacity (FVC) 80.7%, and FEV1/FVC 82.5%. Echocardiography (ECHO) images were reviewed, left ventricular (LV) structure and performance did not differ between obstructive and nonobstructive pulmonary function test (PFT) groups, but values of LV longitudinal strain were 4.8% lower than expected normal for adults. Patients with obstructive PFT had additional decreased right ventricular (RV) function by ECHO.

CONCLUSION

BPD patients in this study were found to have a burden of cardiorespiratory alterations that persisted into adulthood, with RV performance abnormalities found among patients with obstructive PFT.

KEY POINTS

· BPD patients born at extremes of prematurity have cardiorespiratory alterations in adulthood.. · Among patients with obstructive lung function, subtle cardiac performance abnormalities were found.. · Future directions should include systematic follow-up of premature newborns with BPD..

Geographical Differences and Temporal Improvements in Forced Expiratory Volume in 1 Second of Preterm-Born Children: A Systematic Review and Meta-analysis

Importance

Although preterm birth is associated with later deficits in lung function, there is a paucity of information on geographical differences and whether improvements occur over time, especially after surfactant was introduced.

Objective

To determine deficits in percentage predicted forced expiratory volume in 1 second (%FEV1) in preterm-born study participants, including those with bronchopulmonary dysplasia (BPD) in infancy, when compared with term-born control groups.

Data Sources

Eight databases searched up to December 2021.

Study Selection

Studies reporting spirometry for preterm-born participants with or without a term-born control group were identified.

Data Extraction and Synthesis

Data were extracted and quality assessed by 1 reviewer and checked by another. Data were pooled using random-effects models and analyzed using Review Manager and the R metafor package.

Main Outcomes and Measures

Deficits in %FEV1 between preterm-born and term groups. Associations between deficits in %FEV1 and year of birth, age, introduction of surfactant therapy, and geographical region of birth and residence were also assessed.

Results

From 16 856 titles, 685 full articles were screened: 86 with and without term-born control groups were included. Fifty studies with term controls were combined with the 36 studies from our previous systematic review, including 7094 preterm-born and 17 700 term-born participants. Of these studies, 45 included preterm-born children without BPD, 29 reported on BPD28 (supplemental oxygen dependency at 28 days), 26 reported on BPD36 (supplemental oxygen dependency at 36 weeks' postmenstrual age), and 86 included preterm-born participants. Compared with the term-born group, the group of all preterm-born participants (all preterm) had deficits of %FEV1 of -9.2%; those without BPD had deficits of -5.8%, and those with BPD had deficits of approximately -16% regardless of whether they had BPD28 or BPD36. As year of birth increased, there was a statistically significant narrowing of the difference in mean %FEV1 between the preterm- and term-born groups for the all preterm group and the 3 BPD groups but not for the preterm-born group without BPD. For the all BPD group, when compared with Scandinavia, North America and western Europe had deficits of -5.5% (95% CI, -10.7 to -0.3; P = .04) and -4.1% (95% CI, -8.8 to 0.5; P = .08), respectively.

Conclusions and Relevance

Values for the measure %FEV1 were reduced in preterm-born survivors. There were improvements in %FEV1 over recent years, but geographical region had an association with later %FEV1 for the BPD groups.

Preterm or early term birth and long-term risk of asthma into midadulthood: a national cohort and cosibling study

BACKGROUND

Preterm birth is associated with pulmonary complications early in life; however, long-term risks of asthma into adulthood are unclear.

OBJECTIVE

To determine asthma risks from childhood into adulthood associated with gestational age at birth in a large population-based cohort.

METHODS

A national cohort study was conducted of all 4 079 878 singletons born in Sweden during 1973-2013, followed up for asthma identified from primary care, specialty outpatient and inpatient diagnoses in nationwide registries through 2018 (up to 46 years). Cox regression was used to adjust for potential confounders, and cosibling analyses assessed the influence of unmeasured shared familial (genetic and/or environmental) factors.

RESULTS

In 91.9 million person-years of follow-up, 607 760 (14.9%) persons were diagnosed with asthma. Preterm birth was associated with increased risk of asthma at ages <10 years (adjusted HR 1.73; 95% CI 1.70 to 1.75), 10-17 years (1.29; 1.27 to 1.32) and 18-46 years (1.19; 1.17 to 1.22). Across all ages, adjusted HRs further stratified were 3.01 (95% CI 2.88 to 3.15) for extremely preterm (22-27 weeks), 1.76 (1.72 to 1.79) for very or moderately preterm (28-33 weeks), 1.31 (1.29 to 1.32) for late preterm (34-36 weeks) and 1.13 (1.12 to 1.14) for early term (37-38 weeks), compared with full-term (39-41 weeks) birth. These findings were not explained by shared familial factors. Asthma risks were elevated after spontaneous or medically indicated preterm birth and with or without perinatal respiratory complications.

CONCLUSIONS

In this large national cohort, preterm and early term birth were associated with increased risks of asthma from childhood into midadulthood. Persons born prematurely need long-term follow-up into adulthood for timely detection and treatment of asthma.

Insurance coverage and respiratory morbidities in bronchopulmonary dysplasia

INTRODUCTION

Preterm infants and young children with bronchopulmonary dysplasia (BPD) are at increased risk for acute care utilization and chronic respiratory symptoms during early life. Identifying risk factors for respiratory morbidities in the outpatient setting could decrease the burden of care. We hypothesized that public insurance coverage was associated with higher acute care usage and respiratory symptoms in preterm infants and children with BPD after initial neonatal intensive care unit (NICU) discharge.

METHODS

Subjects were recruited from BPD clinics at 10 tertiary care centers in the United States between 2018 and 2021. Demographics and clinical characteristics were obtained through chart review. Surveys for clinical outcomes were administered to caregivers.

RESULTS

Of the 470 subjects included in this study, 249 (53.0%) received employer-based insurance coverage and 221 (47.0%) received Medicaid as sole coverage at least once between 0 and 3 years of age. The Medicaid group was twice as likely to have sick visits (adjusted odd ratio [OR]: 2.06; p = 0.009) and emergency department visits (aOR: 2.09; p = 0.028), and three times more likely to be admitted for respiratory reasons (aOR: 3.04; p = 0.001) than those in the employer-based group. Additionally, those in the Medicaid group were more likely to have nighttime respiratory symptoms (aOR: 2.62; p = 0.004).

CONCLUSIONS

Children with BPD who received Medicaid coverage were more likely to utilize acute care and have nighttime respiratory symptoms during the first 3 years of life. More comprehensive studies are needed to determine whether the use of Medicaid represents a barrier to accessing care, lower socioeconomic status, and/or a proxy for detrimental environmental exposures.

Longitudinal changes in lung function in very prematurely born young people receiving high-frequency oscillation or conventional ventilation from birth

OBJECTIVE

To examine changes in lung function over time in extremely prematurely born adolescents.

WORKING HYPOTHESIS

Changes in lung function during adolescence would vary by ventilation mode immediately after birth.

STUDY DESIGN

Longitudinal follow-up study.

PATIENT SUBJECT SELECTION

Participants from the United Kingdom Oscillation Study who were randomized at birth to high-frequency oscillation (HFO) or conventional ventilation (CV) were assessed at 11-14 years (n = 319) and at 16-19 years (n = 159).

METHODOLOGY

Forced expiratory flow (FEF), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and lung volumes including functional residual capacity (FRC) were reported as z-scores. The diffusion capacity of the lungs for carbon monoxide (DLCO) was measured. Lung function trajectories were compared by mode of ventilation using mixed models. Changes in z-scores were scaled to 5-year average follow-up.

RESULTS

There were significant changes in the mean FEF75, FEF50, FEF25, FEV1, FVC, and DLCO z-scores within the CV and HFO cohorts, but no significant differences in the changes between the two groups. The mean FRC z-score increased in both groups, with an average change of greater than one z-score. The mean FEV1/FVC z-score increased significantly in the CV group, but not in the HFO group (difference in slopes: p = 0.02). Across the population, deterioration in lung function was associated with male sex, white ethnicity, lower gestational age at birth, postnatal corticosteroids, oxygen dependency at 36 weeks postmenstrual age, and lower birth weight, but not ventilation mode.

CONCLUSIONS

There was little evidence that the mode of ventilation affected changes in lung function over time.

The extremely preterm young adult - State of the art

Recently several studies have reported adult outcomes for individuals born at extremely low gestations, although they tend to be included as part of slightly more mature populations. The growth in collaborative studies allows greater confidence in the identification of persisting risk and allows us to have confidence in the likely outcomes in more contemporary cohorts. This review shows the persistence of adverse outcomes through to adult life and includes a range of outcomes including all body systems evaluated. Nonetheless adult outcomes demonstrate that most survivors appear to be free of major disabling conditions and demonstrate good participation in society. Several studies have reported outcomes in the third decade, but subsequent ageing trajectories have not yet been defined. The stability of many of the outcomes evaluated over childhood into adult life and the lack of improvement in prevalence of childhood impairments found in contemporary cohorts indicates persisting levels of risk.

Respiratory responses to hypoxia during rest and exercise in individuals born pre-term: a state-of-the-art review

The pre-term birth survival rate has increased considerably in recent decades, and research investigating the long-term effects of premature birth is growing. Moreover, altitude sojourns are increasing in popularity and are often accompanied by various levels of physical activity. Individuals born pre-term appear to exhibit altered acute ventilatory responses to hypoxia, potentially predisposing them to high-altitude illness. These impairments are likely due to the use of perinatal hyperoxia stunting the maturation of carotid body chemoreceptors, but may also be attributed to limited lung diffusion capacity and/or gas exchange inefficiency. Aerobic exercise capacity also appears to be reduced in this population. This may relate to the aforementioned respiratory impairments, or could be due to physiological limitations in pulmonary blood flow or at the exercising muscle (e.g. mitochondrial efficiency). However, surprisingly, the debilitative effects of exercise when performed at altitude do not seem to be exacerbated by premature birth. In fact, it is reasonable to speculate that pre-term birth could protect against the consequences of exercise combined with hypoxia. The mechanisms that underlie this assertion might relate to differences in oxidative stress responses or in cardiopulmonary morphology in pre-term individuals, compared to their full-term counterparts. Further research is required to elucidate the independent effects of neonatal treatment, sex differences and chronic lung disease, and to establish causality in some of the proposed mechanisms that could underlie the differences discussed throughout this review. A more in-depth understanding of the acclimatisation responses to chronic altitude exposures would also help to inform appropriate interventions in this clinical population.

Bronchopulmonary dysplasia and expiratory airflow at 8 years in children born extremely preterm in the post-surfactant era

BACKGROUND

It is unclear if bronchopulmonary dysplasia (BPD) is independently associated with reduced expiratory airflow at school age.

OBJECTIVE

To determine the independent associations of moderate-severe BPD, mild BPD, gestational age and birth weight z-score with expiratory airflow in children born extremely preterm (EP; <28 weeks' gestation).

METHODS

All EP survivors born in Victoria, Australia, in three eras (1991-1992, n=225; 1997, n=151; and 2005, n=170) were recruited at birth and 418/546 (77%) had valid spirometry data at 8 years. BPD was classified as moderate-severe (oxygen requirement at 36 weeks' postmenstrual age), or mild (oxygen >28 days but not at 36 weeks' postmenstrual age). Expiratory airflow variables, including the forced expired volume in 1 s (FEV₁), were measured and values converted to z-scores.

RESULTS

Compared with no BPD (n=94), moderate-severe BPD (n=193) was associated with a substantial reduction in expiratory airflow (eg, zFEV₁ mean difference -0.69, 95% CI -0.97 to -0.41; p<0.001), but mild BPD (n=131) was not (zFEV₁ mean difference 0.01, 95% CI -0.28 to 0.31; p=0.93). On multivariable analysis, moderate-severe BPD remained strongly associated with reduced airflow (zFEV₁ mean difference -0.63, 95% CI -0.92 to -0.33; p<0.001), but mild BPD (zFEV₁ mean difference 0.04, 95% CI -0.26 to 0.34; p=0.27), gestational age (zFEV₁ 0.06 mean increase per week, 95% CI -0.05 to 0.17; p=0.29) and birth weight z-score (zFEV₁ 0.07 mean increase per SD, 95% CI -0.06 to 0.20; p=0.28) were not.

CONCLUSIONS

In children born EP, moderate-severe BPD, but not mild BPD was independently associated with reduced expiratory airflow at 8 years.

Pulmonary Magnetic Resonance Imaging of Ex-preterm Children with/without Bronchopulmonary Dysplasia

RATIONALE

Children born prematurely, particularly those with bronchopulmonary dysplasia, have persisting lung abnormalities requiring longitudinal monitoring. Pulmonary ultra-short echo time magnetic resonance imaging (MRI) measurements may provide sensitive markers of persisting lung abnormalities, and have not been evaluated in school-aged children born prematurely.

OBJECTIVE

To compare pulmonary MRI and pulmonary function test measurements in preterm-born school-aged children with and without bronchopulmonary dysplasia.

METHODS

Children aged 7-9 years, born extremely preterm, with and without bronchopulmonary dysplasia, were recruited from three centers. Participants underwent pulmonary ultra-short echo time MRI and pulmonary function tests. Primary outcomes included total proton density and proton density at full expiration, measured using MRI. Multiple linear regression analysis was performed, adjusting for gestational age and bronchopulmonary dysplasia. Associations between MRI and pulmonary function were tested.

RESULTS

Thirty-five children were included in the primary analysis (24 with bronchopulmonary dysplasia, 11 without); 29 completed pulmonary function tests, of whom 11 (38%) had airflow limitation. Children with bronchopulmonary dysplasia had 44% (CI: 10%, 66%) lower mean total proton density (mean ± SD: 3.6 ± 2.6) compared to those without (6.1 ± 4.0). Those with bronchopulmonary dysplasia had 25% (CI: 3%, 42%) lower proton density at full expiration than those without. Lower total proton density and proton density at full expiration were moderately correlated with greater residual volume, residual volume/total lung capacity, and lung clearance index (Spearman correlations for total proton density: -0.42, -0.57, and -0.53, respectively. Spearman correlations for proton density at full expiration: -0.28, -0.57, and -0.45, respectively).

CONCLUSIONS

School-aged preterm-born children with bronchopulmonary dysplasia have parenchymal tissue abnormalities measured using ultrashort MRI proton density, compared to those without. MRI proton density correlated with pulmonary function measures indicative of gas trapping. Clinical trial registered with ClinicalTrials.gov (NCT02921308).

Effect of human milk and other neonatal variables on lung function at three months corrected age

OBJECTIVE

To evaluate the impact of human milk and different neonatal variables on tidal breathing flow-volume loop (TBFVL) parameters within three months' corrected age (CA) in infants born ≤32 wks or weighing <1500 g.

METHODS

We retrospectively studied 121 infants with gestational age (GA) ≤ 32 weeks or birth weight (BW) <1500 gr who had lung function assessment within three months' CA by TBFVL analysis between June 2009 and April 2018. We investigated the impact of GA, gender, being Small for GA (SGA), sepsis, days of mechanical ventilation (MV) and human milk feeding (HMF) on later respiratory function, both in the entire group and according to BW ( ≤1000 g and >1000 g).

RESULTS

The mean(SD) z-score for tidal volume (Vt) and time to peak expiratory flow to expiratory time (tPTEF/tE) were respectively -4.3 (2.5) and -0.8 (2.0) for the overall population with no significant differences between infants <1000 g or ≥1000 g. The mean(SD) Vt standardized for body weight was 6.2(2.0) ml/kg. Being female was associated with better Vt/Kg, whereas longer MV or being born SGA were associated with worst tPTEF/tE. For infants with BW < 1000 gr, tPTEF/tE was positively associated with HMF.

CONCLUSION

An early TBFVL assessment within three months' CA already reveals lung function alteration in preterm infants. Being female is associated with better Vt/Kg, while longer duration of MV or being born SGA negatively affect tPTEF/tE. The positive association between HMF and better tPTEF/tE in infants with BW <1000 g has emerged, which deserves further investigation.

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.

Outcomes into adulthood of infants born extremely preterm

As survival of infants born extremely preterm increases, more are now reaching adulthood. It is well documented that survivors born extremely preterm experience more developmental delay and disability in multiple domains compared with term-born controls in early childhood and school age. However, with increasing age, health problems involving physical and mental health become more evident. Despite these challenges, it is reassuring that self-reported quality of life remains good. Future directions of research include development of age-appropriate interventions to optimise health and development of individuals born extremely preterm beyond school age.

Bronchopulmonary dysplasia as a determinant of respiratory outcomes in adult life

Respiratory disease is unfortunately common in preterm infants with the archetype being bronchopulmonary dysplasia (BPD). BPD affects approximately 50,000 preterm infants in the U.S. annually with substantial morbidity and mortality related to its pathology (alveolar, airway, and pulmonary vasculature maldevelopment). Predicting the likelihood and severity of chronic respiratory disease in these children as they age is difficult and compounded by the lack of consistent phenotyping. Barriers to understanding the actual scope of this problem include few longitudinal studies, information limited by small retrospective studies and the ever-changing landscape of therapies in the NICU that affect long-term respiratory outcomes. Thus, the true burden of adult respiratory disease caused by premature birth is currently unknown. Nevertheless, limited data suggest that a substantial percentage of children with a history of BPD have long-term respiratory symptoms and persistent airflow obstruction associated with altered lung function trajectories into adult life. Small airway disease with variable bronchodilator responsiveness, is the most common manifestation of lung dysfunction in adults with a history of BPD. The etiology of this is unclear however, developmental dysanapsis may underlie the airflow obstruction in some adults with a history of BPD. This type of flow limitation resembles that of aging adults with chronic obstructive lung disease with no history of smoking. It is also unclear whether lung function abnormalities in people with a history of BPD are static or if these individuals with BPD have a more accelerated decline in lung function as they age compared to controls. While some of the more significant mediators of lung function, such as tobacco smoke and respiratory infections have been identified, more work is necessary to identify the best means of preserving lung function for individuals born prematurely throughout their lifespan.

The high-risk factors of different severities of bronchopulmonary dysplasia (BPD) based on the national institute of child health and human development (NICHD) diagnosis criteria in 2018

Objective

To investigate the clinical characteristics of preterm infants with different severities of bronchopulmonary dysplasia (BPD) and disclose the high-risk factors of exacerbating BPD.

Methods

Collection of clinical data of 91 preterm infants admitted to the NICU and diagnosed with BPD, categorized in groups according to the disease severity: 41 mild cases,, 24 moderate cases, and 26 severe cases. Comparison and analysis of perinatal risk factors, treatment, complications and prognosis of the infants with different severity degrees.

Results

The severe group had a higher proportion of infants with congenital heart disease (CHD) higher than the moderate group (P < 0.05), and a higher ratio of pneumonia and mechanical ventilation (MV) ≥ seven days than the mild group (P < 0.05). The severe group also presented higher reintubation incidence than both the mild and moderate groups (P < 0.05). The groups presented different (P < 0.05) incidence rates of hemodynamically significant patent ductus arteriosus (hsPDA) . Ridit analysis suggested that the premature infants (PIs) with hsPDA, multiple microbial pulmonary infections, or Klebsiella pneumoniae pneumonia had more severe illness.

Conclusion

CHD, hsPDA, MV ≥ seven days, reintubation, pneumonia, especially multiple microbial pulmonary infections, and Klebsiella pneumoniae pneumonia are correlated with the severity of BPD and can be used as BPD progression predictor.

Lung function between 8 and 15 years of age in very preterm infants with fetal growth restriction

BACKGROUND

The impact of intrauterine growth restriction (IUGR) on lung function in very preterm children is largely unknown as current evidence is mainly based on studies in children born small for gestational age but not necessarily with IUGR.

METHODS

Spirometry, transfer factor of the lung for carbon monoxide (TLco), and lung clearance index (LCI) were cross-sectionally evaluated at 8.0-15.0 years of age in children born <32 weeks of gestation with IUGR (n = 28) and without IUGR (n = 67). Controls born at term (n = 67) were also included.

RESULTS

Very preterm children with IUGR had lower mean forced expired volume in the first second (FEV₁) z-score than those with normal fetal growth (∆ -0.66, 95% confidence interval (CI) -1.12, -0.19), but not significant differences in LCI (∆ +0.24, 95% CI -0.09, 0.56) and TLco z-score (∆ -0.11, 95% CI -0.44, 0.23). The frequency of bronchopulmonary dysplasia (BPD) in the two groups was, respectively, 43% and 10% (P = 0.003). IUGR was negatively associated with FEV₁ (B = -0.66; P = 0.004), but the association lost significance (P = 0.05) when adjusting for BPD.

CONCLUSIONS

IUGR has an impact on conducting airways function of very preterm children at school age, with part of this effect being mediated by BPD. Ventilation inhomogeneity and diffusing capacity, instead, were not affected.

IMPACT

IUGR does not necessarily imply a low birthweight for gestational age (and vice versa). While a low birthweight is associated with worse respiratory outcomes, the impact of IUGR on lung function in premature children is largely unknown. IUGR affects conducting airways function in school-age children born <32 weeks with IUGR, but not ventilation inhomogeneity and diffusing capacity. The impact of IUGR on FEV₁ seems mainly related to the higher risk of BPD in this group.

Wildfire smoke exposure and respiratory health outcomes in young adults born extremely preterm or extremely low birthweight

OBJECTIVE

Adults born either extremely preterm (EP, <28 weeks gestation) or extremely low birthweight (ELBW, <1000 g birthweight) have more obstructive airflow than controls of normal birthweight (>2499 g). We compared self-reported adverse respiratory health outcomes in young adults born EP/ELBW with controls following smoke exposure from the 2019/2020 wildfires in the Australian state of Victoria, and explored if any effects were mediated by airway obstruction, reflected in the forced expiratory volume in 1 second (FEV₁).

METHODS

EP/ELBW participants were derived from all survivors born in the state of Victoria in 1991-92. Contemporaneous controls of normal birthweight (>2499 g) were recruited in the newborn period and matched for sociodemographic variables. Both groups had been assessed at intervals through childhood and into adulthood. Those who participated in the most recent follow-up assessment at 25 years of age, when FEV₁ had been measured, were sent a survey when they were approximately 28 years of age asking about respiratory health related outcomes (respiratory symptoms, health services usage, medication uptake) following wildfire smoke exposure over the southern hemisphere summer of 2019-20.

RESULTS

A total of 296 participants (166 EP/ELBW; 130 controls) were sent the survey; 44% of the EP/ELBW group and 47% of the control group responded. Compared with controls, EP/ELBW respondents reported more overall respiratory problems (30%vs 20%) and specific respiratory symptoms (breathlessness, wheezing, cough and chest tightness) following wildfire smoke exposure, as well as higher health services usage (e.g. local health clinic, hospital emergency department) and medication uptake for respiratory-related problems. Higher FEV₁ values were associated with lower odds of most self-reported respiratory symptoms; adjusting for FEV₁ attenuated the differences between EP/ELW and control groups.

CONCLUSION

Survivors born EP/ELBW may be at an increased risk of adverse respiratory health outcomes following wildfire smoke exposure in early adulthood, in part related to worse expiratory airflows.

Respiratory outcomes of "new" bronchopulmonary dysplasia in adolescents: A multicenter study

OBJECTIVE

Long-term respiratory consequences of bronchopulmonary dysplasia (BPD) in preterm infants born in the post-surfactant era ("new" BPD) remain partially unknown. The present study aimed to evaluate the respiratory outcomes of "new" BPD in adolescents who were born preterm.

METHODS

This multicenter, cross-sectional study included 286 adolescents born between 2003 and 2005 (mean age: 14.2 years); among them, 184 and 102 were born extremely preterm (EP; <28 weeks' gestation) and moderate-late preterm (32 to <37 weeks' gestation), respectively. Among EP adolescents, 92 had BPD, and 92 did not. All participants underwent lung function tests, skin prick testing, and questionnaires on asthma symptoms and quality of life.

RESULTS

EP adolescents with BPD had significantly lower forced expiratory volume in 1 s (FEV₁ ), forced vital capacity (FVC), FEV₁ /FVC ratio, and forced expiratory flow between 25% and 75% of FVC than other included adolescents. FEV₁ /FVC ratios were below the lower limit of normal (z-score <-1.645) in 30.4% of EP adolescents with BPD, 13.0% of EP adolescents without BPD, and 11.8% of adolescents who were born moderate-late preterm. Bronchodilator response and air-trapping were significantly higher in BPD adolescents than in other adolescents. Diffusion capacity was significantly lower in EP adolescents than in moderate-late preterm adolescents. Asthma symptoms and quality-of-life scores were similar among groups.

CONCLUSION

EP adolescents with "new" BPD had poorer pulmonary function than EP adolescents without BPD or moderate-late preterm adolescents. Further studies are needed to determine whether "new" BPD is associated with early-onset chronic obstructive pulmonary disease in adulthood.

Understanding hydrogen sulfide signaling in neonatal airway disease

INTRODUCTION

Airway dysfunction leading to chronic lung disease is a common consequence of premature birth and mechanisms responsible for early and progressive airway remodeling are not completely understood. Current therapeutic options are only partially effective in reducing the burden of neonatal airway disease and premature decline of lung function. Gasotransmitter hydrogen sulfide (H2S) has been recently recognized for its therapeutic potential in lung diseases.

AREAS COVERED

Contradictory to its well-known toxicity at high concentrations, H2S has been characterized to have anti-inflammatory, antioxidant, and antiapoptotic properties at physiological concentrations. In the respiratory system, endogenous H2S production participates in late lung development and exogenous H2S administration has a protective role in a variety of diseases such as acute lung injury and chronic pulmonary hypertension and fibrosis. Literature searches performed using NCBI PubMed without publication date limitations were used to construct this review, which highlights the dichotomous role of H2S in the lung, and explores its promising beneficial effects in lung diseases.

EXPERT OPINION

The emerging role of H2S in pathways involved in chronic lung disease of prematurity along with its recent use in animal models of BPD highlight H2S as a potential novel candidate in protecting lung function following preterm birth.

Predicting Long-Term Respiratory Outcomes in Premature Infants: Is It Time to Move beyond Bronchopulmonary Dysplasia?

Premature birth has been shown to be associated with adverse respiratory health in children and adults; children diagnosed with bronchopulmonary dysplasia (BPD) in infancy are at particularly high risk. Since its first description by Northway et al. about half a century ago, the definition of BPD has gone through several iterations reflecting the changes in the patient population, advancements in knowledge of lung development and injury, and improvements in perinatal care practices. One of the key benchmarks for optimally defining BPD has been the ability to predict long-term respiratory and health outcomes. This definition is needed by multiple stakeholders for hosts of reasons including: providing parents with some expectations for the future, to guide clinicians for developing longer term follow-up practices, to assist policy makers to allocate resources, and to support researchers involved in developing preventive or therapeutic strategies and designing studies with meaningful outcome measures. Long-term respiratory outcomes in preterm infants with BPD have shown variable results reflecting not only limitations of the current definition of BPD, but also potentially the impact of other prenatal, postnatal and childhood factors on the respiratory health. In this manuscript, we present an overview of the long-term respiratory outcomes in infants with BPD and discuss the role of other modifiable or non-modifiable factors affecting respiratory health in preterm infants. We will also discuss the limitations of using BPD as a predictor of respiratory morbidities and some of the recent advances in delineating the causes and severity of respiratory insufficiency in infants diagnosed with BPD.

Respiratory and Cardiovascular Outcomes in Survivors of Extremely Preterm Birth at 19 Years

Rationale: Growth and development during adolescence may modify the respiratory and vascular differences seen among extremely preterm (EP) individuals in childhood and early adolescence.Objectives: To assess the trajectory of respiratory and cardiovascular outcomes during transition to adulthood in a national longitudinal cohort study of births before 26 weeks of gestation in the United Kingdom and Ireland.Methods: A total of 129 EP participants and 65 control subjects attended for a center-based evaluation at 19 years of age. Standardized measures of spirometry, hemodynamics, functional capacity, and markers of inflammation were obtained from EP subjects with and without neonatal bronchopulmonary dysplasia and term-born control subjects at 19 years of age and compared with previous assessments.Measurements and Main Results: Compared with the control group, the EP group was significantly impaired on all spirometric parameters (mean FEV₁ z-score, -1.08 SD [95% confidence interval, -1.40 to -0.77]) and had lower fractional exhaled nitric oxide concentrations (13.9 vs. 24.4 ppb; P < 0.001) despite a higher proportion with bronchodilator reversibility (27% vs. 6%). The EP group had significantly impaired exercise capacity. All respiratory parameters were worse after neonatal bronchopulmonary dysplasia, and respiratory function differences were similar at 11 and 19 years. The augmentation index was 6% higher in the EP group and associated with increased total peripheral resistance (difference in means, 96.4 [95% confidence interval, 26.6-166.2] dyne/s/cm^-5) and elevation in central, but not peripheral, blood pressure. Central systolic and diastolic blood pressures increased more quickly during adolescence in the EP group than in the control group.Conclusions: Clinicians should address both cardiovascular and respiratory risks in adult survivors of extremely preterm birth.

An overview of adult health outcomes after preterm birth

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

Cardiovascular Health Profile at Age 25 Years in Adults Born Extremely Preterm or Extremely Low Birthweight

Being born extremely preterm (EP; <28 weeks' gestation) or extremely low birthweight (ELBW; <1000 g birthweight) may predict increased cardiometabolic risk in adulthood, but other early life predictors are less well described. We aimed to (1) compare cardiovascular health profiles between 165 adults born EP/ELBW and 127 controls at age 25 years, drawn from a prospective longitudinal cohort study, recruited at birth in 1991 to 1992; and (2) in the EP/ELBW group, determine early life associations of cardiovascular health. Cardiovascular health profiles were calculated individually for measures of anthropometry, abdominal visceral fat, blood pressure, fasting plasma glucose, insulin, lipids, C-reactive protein, vascular indices, exercise tolerance and smoking status, and summed for an overall score. Cardiovascular health profiles were compared between groups; using logistic regression (individual scores) and the Mann-Whitney U test (cumulative score). Compared with controls, adults born EP/ELBW had less favorable cardiovascular health profiles; individually for abdominal visceral fat (odds ratio, 0.56 [95% CI, 0.33-0.96], P=0.03), blood pressure (odds ratio 0.38 [95% CI, 0.23-0.63], P<0.001), exercise capacity (odds ratio 0.37 [95% CI, 0.22-0.63], P<0.001), and fasting glucose (odds ratio 0.51 [95% CI, 0.31-0.84], P=0.01) and overall (median [interquartile range] 10 [7-11] versus 11 [9-12], P=0.007). Male sex predicted unfavorable abdominal visceral fat, blood pressure and fasting glucose, and favorable exercise capacity. Greater increases in weight Z scores between 2 and 8, and 8 and 18 years predicted less favorable profiles of exercise capacity and visceral fat. Longer-term follow-up is critical to determine the cardiovascular sequelae of adults born EP/ELBW.

Prediction of lung function and lung density of young adults who had bronchopulmonary dysplasia

COPD risk is jointly determined by fetal lung development, lung growth rate and lung growth duration leading to the maximally attained level of lung function in early adulthood. Bronchopulmonary dysplasia (BPD) is considered a developmental arrest of alveolarisation. Long-term outcome studies of adult survivors born before the introduction of surfactant therapy (“old BPD”) showed impaired lung function. We aimed to predict adult lung function and lung density in a cohort of premature infants born in the surfactant era, representing “new BPD”.

We studied a cohort of young adults born between 1987 and 1998, with (n=36) and without (n=28) BPD, treated in a single centre. Their perinatal characteristics and pulmonary function in infancy were studied by regression analysis for correlation with adult lung function and tissue lung density, all expressed by z-scores, at a mean age of 19.7±1.1 and 21±2.2 years, respectively.

Although BPD adults had on average lower forced expiratory volume in 1 s (zFEV₁)/forced vital capacity (FVC) and zFEV₁ than those without, 55% of the BPD group had zFEV1/FVC values above the lower limit of normal (LLN). Moreover, above LLN values of diffusing capacity of the lung for carbon monoxide (zD_LCO) was present in 89% of BPD adults and lung density in 71%. Only higher oxygen supply (F_IO2) at 36 weeks post-conception of BPD subjects had a trend with lower zFEV₁ (B=−6.4; p=0.053) and lower zD_LCO (B=−4.1; p=0.023) at adulthood.

No statistically significant predictors of new BPD were identified.

Neither perinatal clinical parameters nor infant pulmonary function at 1 year corrected age could predict outcomes of adult lung function and lung tissue density in a cohort of adults who survived BPDhttps://bit.ly/3gL6gaU

Using Facebook to Improve Participation Among 25-Year-Olds Enrolled in a Longitudinal Preterm Birth Cohort Study

OBJECTIVE

Facebook is a popular social media platform used globally to keep connected and informed. The aims of this study were to determine the contribution of Facebook to the participation rate of young adults enrolled in a longitudinal cohort study, and to examine systematic differences in participants recruited through Facebook compared with those recruited through traditional methods.

METHODS

Potential participants comprised 297 consecutive survivors born extremely preterm (<28 weeks' gestation) or extremely low birth weight (<1000 g birth weight) in 1991-92 in the state of Victoria, Australia, and 260 contemporaneously recruited normal birth weight (>2499 g birth weight) controls who had participated previously in a prospective cohort study. At 25 years of age participants were approached initially via traditional methods (mail, telephone, texts), and subsequently by Facebook for those difficult to contact or locate.

RESULTS

Contact was attempted with 523 young adults via traditional methods and 49% (n = 255) agreed to participate. Of the 208 participants unable to be located or contacted via traditional methods, 153 were subsequently located via Facebook. Of these 82% (n = 125) responded promptly within a day of receiving the Facebook invite, and 41% (n = 63) ultimately participated. The participation rate increased from 49% (255 of 523) to 61% (318 of 523) with the addition of Facebook, an absolute increase of 12%. Participants recruited by Facebook were slightly older, had lower rates of school completion and lower cognitive score at 18 years of age compared with those recruited via traditional methods.

CONCLUSIONS

Using Facebook improved participation of young adults enrolled in this longitudinal preterm follow up study, 25 years after original recruitment.

Regional ventilation inhomogeneity in survivors of extremely preterm birth

INTRODUCTION

Survivors of extreme prematurity may have disrupted lung development. We hypothesized that the multiple breath washout (MBW) index Scond, which is intended to reflect ventilation inhomogeneity from the conducting airways, could be a sensitive marker of respiratory impairment in this group.

METHODS

Spirometry, TLco, and MBW were cross-sectionally evaluated at 8 to 14 years of age in children born at <28 weeks between 2004 and 2010 in Udine, Italy. Age-matched controls born at term were also included. Bronchopulmonary dysplasia (BPD) was defined as oxygen-dependence at 36 weeks postmenstrual age. The limits of normal were the 5th percentile of the reference population (Global Lung Initiative) for spirometry and TLco and the 95th percentile of controls for Lung Clearance Index, Scond, and Sacin from MBW.

RESULTS

Results were obtained in 47 extremely preterm children (53% boys, mean ± standard deviation age 11.3 ± 2.0 years, 40% with BPD) and 60 controls (50% boys, 11.6 ± 1.9 years). There were significant differences between preterm children and controls in all lung function outcomes, except for Sacin. Among children born <28 weeks, Scond tended to be frequently abnormal than FEV₁ z-score (29% vs 14%, P = .06). At multivariable linear regression, in the preterm group, current asthma was significantly associated with a higher Scond (B = 0.019, 95% confidence interval, 0.000-0.038), whereas BPD was not.

CONCLUSION

Almost a third of extremely preterm children at school age showed Scond alterations that affected also children without BPD. Longitudinal studies should clarify the prognostic meaning of Scond abnormalities in this group.

Phenotypes of Bronchopulmonary Dysplasia in Adults

Bronchopulmonary dysplasia (BPD), first described by Northway in 1967, is a process of neonatal lung injury that is most strongly associated with prematurity. The "old" form of the disease associated with the oxidative damage and volutrauma from perinatal mechanical ventilation has been increasingly supplanted by a "new" form resulting from interrupted growth of the lung at earlier stages of fetal development. Given the significant improvement in the survival of children with BPD since the 1980s, many more of these patients are living into adulthood and are being seen in adult pulmonary practices. In this review, we present three brief vignettes of patients from our practice to introduce three of the major patterns of disease seen in adult survivors of BPD, namely, asthma-like disease, obstructive lung disease, and pulmonary hypertension. Additional factors shown to affect the lives of adult BPD survivors are also discussed. Finally, we discuss insights into the process of transitioning these complex patients from pediatric to adult pulmonary practices. As survivors of BPD enter adulthood and continue to require specialty pulmonary care, awareness of the disease's varied manifestations and responses to treatment will become increasingly important.

Non-invasive Ventilation for Children With Chronic Lung Disease

Advances in medical care and supportive care options have contributed to the survival of children with complex disorders, including children with chronic lung disease. By delivering a positive pressure or a volume during the patient's inspiration, NIV is able to reverse nocturnal alveolar hypoventilation in patients who experience hypoventilation during sleep, such as patients with chronic lung disease. Bronchopulmonary dysplasia (BPD) is a common complication of prematurity, and despite significant advances in neonatal care over recent decades its incidence has not diminished. Most affected infants have mild disease and require a short period of oxygen supplementation or respiratory support. However, severely affected infants can become dependent on positive pressure support for a prolonged period. In case of established severe BPD, respiratory support with non-invasive or invasive positive pressure ventilation is required. Patients with cystic fibrosis (CF) and advanced lung disease develop hypoxaemia and hypercapnia during sleep and hypoventilation during sleep usually predates daytime hypercapnia. Hypoxaemia and hypercapnia indicates poor prognosis and prompts referral for lung transplantation. The prevention of respiratory failure during sleep in CF may prolong survival. Long-term oxygen therapy has not been shown to improve survival in people with CF. A Cochrane review on the use NIV in CF concluded that NIV in combination with oxygen therapy improves gas exchange during sleep to a greater extent than oxygen therapy alone in people with moderate to severe CF lung disease. Uncontrolled, non-randomized studies suggest survival benefit with NIV in addition to being an effective bridge to transplantation. Complications of NIV relate mainly to prolonged use of a face or nasal mask which can lead to skin trauma, and neurodevelopmental delay by acting as a physical barrier to social interaction. Another associated risk is pulmonary aspiration caused by vomiting whilst wearing a face mask. Adherence to NIV is one of the major barriers to treatment in children. This article will review the current evidence for indications, adverse effects and long term follow up including adherence to NIV in children with chronic lung disease.