Children who are born preterm have an increased risk of developing asthma and wheezing disorders during childhood, according to new research published in PLOS Medicine.

The study findings are based on research done in collaboration between investigators from Maastricht University Medical Centre, The Netherlands, The University of Edinburgh, Scotland, and colleagues at Harvard Medical School. Participating researchers performed 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, or before 37 weeks of gestation, were nearly 46% more likely to develop asthma or a wheezing disorder during childhood, compared to babies born full term – 37 or more weeks of gestation.

What’s more, the authors found that children born very preterm, less than 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 estimated that if no preterm births had occurred, there would have been more than a 3.1% reduction in childhood wheezing disorders.

“There is compelling evidence that preterm birth – particularly very preterm birth – increases the risk of asthma,” the authors wrote. “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.”