Preterm birth is associated with increased risk of asthma and wheezing disorders

The research by Jasper Been, from the Maastricht University Medical Centre (Netherlands) and The University of Edinburgh (UK), and colleagues at Harvard Medical School (US) is a systematic review and meta-analysis of 30 unique studies that collectively involved approximately 1.5 million children. The authors found that children born preterm (before 37 weeks of gestation) were about 46% more likely to develop asthma or a wheezing disorder during childhood, than babies at full term (≥ 37 weeks of gestation). The authors also found that children born very preterm (<32 weeks of gestation) were at even higher risk of developing asthma or a wheezing disorder, almost three times as likely as children born at full term. The authors estimate that if no preterm births had occurred, there would have been more than a 3.1% reduction in childhood wheezing disorders.

The findings are important because increasing numbers of preterm babies survive today thanks to improvements in the management of prematurity, with approximately 11% of children now being born preterm. However, accumulating evidence suggests that early life events are involved in the subsequent development of non-communicable diseases. Given the increasing burden of preterm birth, a better understanding of the long-term effects of preterm birth is essential.

The authors say, "[t]he current findings do not support prior suggestions that the association between preterm birth and wheezing disorders becomes less prominent with increasing age [...] Instead, the strength of the association was similar across age groups [up to 18 years], suggesting that the pulmonary consequences of preterm birth tend to persist throughout the life course."

They conclude, "[t]here is compelling evidence that preterm birth -- particularly very preterm birth -- increases the risk of asthma. Given the projected global increases in children surviving preterm births, research now needs to focus on understanding underlying mechanisms, and then to translate these insights into the development of preventive interventions."