Background: Prevalence of wheezing during infancy and pre-school age among very low birth weight (VLBW) infants is high. There is too little data to determine exactly the cause of wheezing in this group of children--it may result from early neonatal lung injury or increased susceptibility for allergic reactions.
Aim: Analysis of wheezing episodes up to 5-7 years of age in a group of VLBW infants and recognition of risk factors.
Methods: A sample of 104 children aged 5-7 years with birth weight < or = 1500g was prospectively evaluated. The standardized ISAAC (International Study of Asthma and Allergies in Childhood) protocol was used to evaluate the number and quality of wheezing episodes. Total IgE level, specific IgE, lymphocyte Th1/Th2 ratio and skin prick tests (SPT) were performed. Children were divided into 3 groups: without wheezing, with episodes of wheezing in the history (more than 12 months previously), and with persistent episodes of wheezing.
Results: Episodes of wheezing were diagnosed in 52 (50%) cases: 27% of children showed signs of wheezing during 12 previous months and 23% of children reported wheezing only in their past history. Children with persistent wheezing presented more frequently than other groups: positive family history for atopy, allergic rhinitis, and positive allergic laboratory markers. Children with wheezing only during early infancy had bronchopulmonary dysplasia and more severe respiratory distress syndrome after birth.
Conclusion: Prevalence of wheezing during infancy and preschool age among VLBW infants is high. Chronic and recurrent episodes of wheezing are more directly related to atopy than derive from neonatal problems.