Researchers at Brigham and Women's Hospital (BWH) in Boston, Massachusetts, in collaboration with investigators at the Maastricht University Medical Centre and Maastricht University School of Public Health in the Netherlands and The University of Edinburgh in the United Kingdom, have published findings strongly suggesting that preterm birth (prior to 37 weeks gestation) increases the risk of asthma and wheezing disorders during childhood and that the risk of developing these conditions increases as the degree of prematurity increases.

The findings are based on a systematic review and meta-analysis of 30 studies that investigated the association between preterm birth and asthma/wheezing disorders among 1.5 million children. These studies were conducted between 1995 and the present, a time span chosen to allow for recent changes in the management of prematurity.

Across the studies, 13.7 percent of preterm babies developed asthma/wheezing disorders compared with 8.3 percent of babies born at term, representing a 70 percent increased risk. Children born very early (before 32 weeks gestation) had approximately three times the risk of developing asthma/wheezing disorders compared with babies born at term.

"Worldwide, more than 11 percent of babies are born preterm," said Aziz Sheikh, MD, corresponding author and Harkness Fellow in Health Care Policy and Practice in the Division of General Internal Medicine and Primary Care at Brigham and Women's Hospital. "As asthma is a chronic condition, our findings underscore the need to improve our understanding of the mechanisms underlying the association between preterm birth and asthma/wheezing disorders in order to develop preventive and therapeutic interventions."