Respiratory symptoms at age 8 years in a cohort of very low birth weight children.

The childhood respiratory consequences of very low birth weight (birth weight < or =1,500 g) are incompletely understood, especially since the introduction of recent changes in neonatal care. To assess prevalence, trends, and risk factors for respiratory symptoms, the authors followed to age 8 years a cohort of 384 very low birth weight children from six regional neonatal intensive care units in Wisconsin and Iowa who were born between August 1, 1988, and June 30, 1991. A control group of 154 Wisconsin schoolchildren was also assembled. Respiratory symptoms in the past 12 months and history of asthma ("asthma ever") were reported by parents on a questionnaire used in the International Study of Asthma and Allergies in Childhood (ISAAC). Control group prevalence resembled ISAAC prevalence worldwide and in Canada, but respiratory symptoms were twice as common among very low birth weight children. With advent of the availability of pulmonary surfactants, the prevalence of wheezing at age 8 decreased from 50% to 16% (p = 0.002) among children with bronchopulmonary dysplasia, but it increased from 14% to 38% among those with milder neonatal respiratory disease. Bronchopulmonary dysplasia, family history of asthma, smoking in the household, and patent ductus arteriosus were predictive of wheezing in the previous 12 months. Antenatal steroid therapy had a borderline-significant protective association with wheezing (odds ratio = 0.56, 95% confidence interval: 0.29, 1.1). There were interaction effects between several of the predictors.