History of airway disease
Children born very preterm had significantly more respiratory symptoms than term controls (Table 1). Caregivers reported that 59/136 (43%) children born very preterm had experienced at least one out of four symptoms related to airflow obstruction (any history of wheezing, exercise-induced wheezing, nocturnal cough without infection, sleep disturbed by wheezing) compared to 12/56 (21%) children born at term (p=0.004). Wheezing was the most common symptom, reported in 52/136 (38%) children born very preterm compared to 8/56 (14%) children born at term (p=0.001). There were no differences in symptoms within the preterm group between children with or without a diagnosis of BPD.
There were no associations between antenatal exposures and later airway symptoms except that children born preterm after maternal infection or after clinical chorioamnionitis had twice as often experienced nocturnal wheezing (34% versus 16% for maternal infection, p=0.042, and 50.0% versus 23.5% for chorioamnionitis, p=0.052) than children without these exposures. There were no associations between respiratory support (CPAP or ventilator days) in the neonatal period and airway symptoms at school age.
A diagnosis of asthma was more common in children born very preterm than in the term-born controls (36% versus 11%, p<0.001), but equally common in very preterm children with or without BPD. None of the children had any mechanical respiratory support or supplemental oxygen at the time of the lung function study.