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Health professionals have an increasing tendency to work in silos despite the explosion of knowledge indicating that most diseases span the life course. Furthermore, it is increasingly difficult to interest busy adult physicians about the importance of early causation of diseases with which they regularly interact. Why should healthcare teams dealing with COPD and other disorders presenting in adult life, or paediatricians specialising in respiratory care, be interested in the outcomes of babies born premature?
The answer is there is mounting evidence that virtually all chest diseases have their origins in childhood, and for many the die is cast well before birth—through a combination of external influences such as nicotine use and air pollution, and the secondary effects of reduced fetal growth, infection and poor nutrition. Among individuals precise causative pathways may differ, but many more patients are now presenting in childhood or early adult life with evidence of increased risk of future respiratory morbidity. Understanding how this risk has occurred and the implications for adult morbidity are key areas of interest that impact on practice across the full lifespan. To do this we need to join up efforts in obstetrics, neonatology, paediatrics and adult practice.
In this edition of Thorax, Bardsen et al 1 demonstrate that premature birth has long-lasting effects on lung growth and development well into the fourth decade of life. They have followed Norwegian babies with extreme prematurity (EP; born before 28 weeks of gestation or with <1000 g birth weight) up to 35 years of age showing tracking of their lung function. Of more concern they also show that one in three EP participants meet the postbronchodilator spirometry criteria for COPD diagnosis and this was not necessarily in those diagnosed with bronchopulmonary dysplasia (BPD) in the newborn period. The survival rates of babies born at extremely low gestational ages continue to increase, thus ensuring that this population of graduates will grow in numbers as the years progress.
Many longitudinal studies are now assessing survivors after entering adult life. In a systematic review, Doyle et al 2 evaluated the maximal lung function attained following extremely preterm birth in late adolescence or early adult life (mean age at lung function testing was 21 years) in 11 studies. They observed reduced lung function with greater likelihood of COPD in later life.
Bardsen and colleagues1 suggest antenatal factors other than neonatal BPD may be more important, a finding noted in other neonatal studies.3 4 It is crucial to recognise, however, that neonatal lung disease is a continuum with BPD at the more severe end of the spectrum. However, BPD is not a distinct entity due to it having multiple aetiologies which encompass many of the pathways described above.5 Recent evidence has suggested that the risk of clinical asthma is also a continuum, being highest in the most preterm but is increased following late preterm (35–36 weeks of gestation) and early term (37–39 weeks) birth as well. As the latter two categories contain greater numbers of babies than those classed as ‘very preterm’, they will contribute the majority of attributable risk.6 All these important exposures in early life have profound implications for adult disease.7
The adult pattern of disease following neonatal BPD also shows mixed fixed and reversible airflow patterns, but we, among others, failed to find evidence of ongoing lung inflammation,8 suggesting structural deficits. Furthermore, lung morbidity among extremely preterm adults is associated with many other important morbidities, including cognitive impairment9 and cardiovascular disease,7 8 10 11 all of which may contribute to decreased longevity.
The challenge for everyone is to recognise as early as possible those at risk and to ensure their comprehensive respiratory follow-up in childhood through adult life. Neonatologists need to reconnect with paediatric respiratory specialists to identify this important group for adult respiratory services to take on board through joint transition clinics, as has been happening in patients with cystic fibrosis for many years. The process commences by simply taking a perinatal history.12 Those at risk deserve better attention and an approved and funded preventative health programme. This should include research studies to minimise further lung damage to prevent progression and complement the extensive perinatal/neonatal work on prevention of early lung injury. We have the evidence on which to build a better future, but unless we all work together with a plan supported by healthcare managers it will come to no avail. We owe it to the future respiratory health of the nation to succeed.
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This study does not involve human participants.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Commissioned; externally peer reviewed.