Upper Airway Pathology Contributes to Respiratory Symptoms in Children Born Very Preterm

Novel Connections of Common Childhood Illnesses Based on More Than 5 Million Diary Registrations From Birth Until Age 3 Years

BACKGROUND

All children experience numerous episodes of illness during the first 3 years of life. Most episodes are mild and handled without medical attention but nevertheless burden the families and society. There is a large, and still unexplained, variation in the burden of illness between children.

OBJECTIVE

To describe and provide a better understanding of the disease burden of common childhood diseases through a data-driven approach investigating the communalities between symptom patterns and predefined variables on predispositions, pregnancy, birth, environment, and child development.

METHODS

The study is based on the prospectively followed clinical mother-child cohort COpenhagen Prospective Studies on Asthma in Childhood, which includes 700 children with daily symptom registration in the first 3 years of life, including symptoms of cough, breathlessness, wheeze, cold, pneumonia, sore throat, ear infections, gastrointestinal infections, fever, and eczema. First, we described the number of episodes of symptoms. Next, factor analysis models were used to describe the variation in symptom load in the second year of life (both based on n = 556, with >90% complete diary). Then we characterized patterns of similarity between symptoms using a graphical network model (based on n = 403, with a 3-year monthly compliance of >50%). Finally, predispositions and pregnancy, birth, environmental, and developmental factors were added to the network model.

RESULTS

The children experienced a median of 17 (interquartile range, 12-23) episodes of symptoms during the first 3 years of life, of which most were respiratory tract infections (median, 13; interquartile range, 9-18). The frequency of symptoms was the highest during the second year of life. Eczema symptoms were unrelated to the other symptoms. The strongest association to respiratory symptoms was found for maternal asthma, maternal smoking during the third trimester, prematurity, and CDHR3 genotype. This was in contrast to the lack of associations for the well-established asthma locus at 17q21.

CONCLUSIONS

Healthy young children are burdened by multiple episodes of symptoms during the first 3 years of life. Prematurity, maternal asthma, and CDHR3 genotype were among the strongest drivers of symptom burden.

Voice and Exercise Related Respiratory Symptoms in Extremely Preterm Born Children After Neonatal Patent Ductus Arteriosus

Objective: To investigate voice characteristics and exercise related respiratory symptoms in extremely preterm born 11-year-old children, focusing particularly on associations with management of a patent ductus arteriosus (PDA). Study design: Prospective follow-up of all children born in Norway during 1999-2000 at gestational age <28 weeks or with birthweight <1,000 g. Neonatal data were obtained prospectively on custom-made registration forms completed by neonatologists. Voice characteristics and exercise related respiratory symptoms were obtained at 11 years by parental questionnaires. Result: Questionnaires were returned for 228/372 (61%) eligible children, of whom 137 had no history of PDA. PDA had been noted in 91 participants, of whom 36 had been treated conservatively, 21 with indomethacin, and 34 with surgery. Compared to the children treated with indomethacin or conservatively, the odds ratio (95% confidence interval) for the surgically treated children were 3.4 (1.3; 9.2) for having breathing problems during exercise, 16.9 (2.0; 143.0) for having a hoarse voice, 4.7 (1.3; 16.7) for a voice that breaks when shouting, 4.6 (1.1; 19.1) for a voice that disturbs singing, and 3.7 (1.1; 12.3) for problems shouting or speaking loudly. The significance of surgery per se was uncertain since the duration of mechanical ventilation was associated with the same outcomes. Conclusion: Extremely preterm born children with a neonatal history of PDA surgery had more problems with voice and breathing during exercise in mid-childhood than those whose PDA had been handled otherwise. The study underlines the causal heterogeneity of exercise related respiratory symptoms in preterm born children.

Recent advances in our understanding of the mechanisms of lung alveolarization and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the most common cause of morbidity and mortality in preterm infants. A key histopathological feature of BPD is stunted late lung development, where the process of alveolarization-the generation of alveolar gas exchange units-is impeded, through mechanisms that remain largely unclear. As such, there is interest in the clarification both of the pathomechanisms at play in affected lungs, and the mechanisms of de novo alveoli generation in healthy, developing lungs. A better understanding of normal and pathological alveolarization might reveal opportunities for improved medical management of affected infants. Furthermore, disturbances to the alveolar architecture are a key histopathological feature of several adult chronic lung diseases, including emphysema and fibrosis, and it is envisaged that knowledge about the mechanisms of alveologenesis might facilitate regeneration of healthy lung parenchyma in affected patients. To this end, recent efforts have interrogated clinical data, developed new-and refined existing-in vivo and in vitro models of BPD, have applied new microscopic and radiographic approaches, and have developed advanced cell-culture approaches, including organoid generation. Advances have also been made in the development of other methodologies, including single-cell analysis, metabolomics, lipidomics, and proteomics, as well as the generation and use of complex mouse genetics tools. The objective of this review is to present advances made in our understanding of the mechanisms of lung alveolarization and BPD over the period 1 January 2017-30 June 2019, a period that spans the 50th anniversary of the original clinical description of BPD in preterm infants.