Extremely Preterm Infants May Have Long-Term Respiratory Morbidity

Infants born extremely preterm (EP) have an increased risk of suffering from respiratory morbidity, airway obstruction, and increased bronchial responsiveness, according to a new study.

Researchers at the University of Nottingham (United Kingdom) and University College London (UCL; United Kingdom) assessed the degree of respiratory morbidity and functional impairment in EP children, in relation to neonatal determinants and current clinical status. To do so, pre- and post-bronchodilator spirometry reading were undertaken in EP children aged 11 years old, as well as in classroom controls at the same school. Physical examination and respiratory health questionnaires were completed and analyzed to estimate the predictive power of potential determinants of lung function. In all, spirometry was obtained in 182 out of 219 EP children--129 of these with prior bronchopulmonary dysplasia (BPD)--and in 161 out of 169 classmates, matched for age, sex, and ethnic group.

The results showed that the EP children had significantly more chest deformities and respiratory symptoms than classmates did, with twice as many diagnosed with asthma. Baseline spirometry was significantly reduced and bronchodilator responsiveness increased in those born EP, with changes being most marked in those with prior BPD. EP birth, BPD, current symptoms, and treatment with beta-agonists were each associated independently with lung function (adjusted for age, sex, and height). However, while 56% percent of EP children had abnormal baseline spirometry and 27% had a positive bronchodilator response, less than half of those with impaired lung function were actually receiving any medication. The study was published ahead of the print in the April 8, 2010, online edition of the American Journal of Respiratory and Critical Care Medicine.

"The fact that many EP children were asymptomatic despite lung function impairment reflects the fact that there is considerable lung reserve during middle childhood,” said lead Janet Stocks, Ph.D., from the Institute of Child Health at UCL. "As the lungs grow and airway caliber increases, such children will be far less prone to wheezing episodes and will appear to have 'grown out' of their symptoms. However, there is concern that such symptoms may reappear in later life in the form of early onset chronic obstructive lung disease.”

"While we do not yet know what effects EP birth has beyond the age of 11, one can surmise that respiratory problems will likely get worse, not better, and that early monitoring and appropriate treatment could minimize greater problems down the line,” added Dr. Stocks. "Similarly, adult chest physicians need to become more aware of the potential long-term respiratory impact of preterm birth and include neonatal details when taking medical histories.”

Related Links:
University of Nottingham
University College London