Reduced neonatal lung function and wheezing illnesses during the first 5 years of life.

Studies of reduced neonatal lung function and wheezing illnesses during childhood show conflicting results. The aim of our study was to assess the association between resistance (Rrs) and compliance (Crs) of the respiratory system by using the single occlusion technique (SOT) and prospectively collected wheezing illnesses during the first 5 years of life in a large birth cohort. SOT was performed during natural sleep before the age of 2 months. Information about wheezing illnesses was collected from the electronic patient file. 549 infants had a successful SOT measurement and complete medical records. Every kPa·L(-1)·s(-1) increase in Rrs was associated with 10% more consultations in the first 3 years of life. Every 10 mL·kPa(-1) increase in Crs was associated with a 14% reduction in consultations in the first 3 years of life, 27% in the fourth to fifth years of life, and a lower probability of having asthma at the age of 5 years (OR 0.66). Children with late-onset or persistent wheezing had significant lower Crs values than their peers. An increased neonatal resistance is associated with more wheezing illnesses during infancy, while a reduced neonatal compliance is associated with more wheezing illnesses during the first 5 years of life, a late-onset or persistent wheezing phenotype, and asthma.