Asthma and lung function in adulthood after a viral wheezing episode in early childhood

Background Viral aetiology of infection has a significant role in the long-term outcome of early-childhood wheezing. Objective This study examines asthma and lung function in adulthood after early-childhood wheezing induced by respiratory syncytial virus (RSV) and rhinovirus (RV). Methods A total of 100 children were hospitalized for a wheezing episode at less than 24 months of age from 1992 to 1993 in Kuopio University Hospital (Finland). Adenovirus, influenza A and B virus, parainfluenza (1-3) virus, and RSV were tested on admission using antigen detection and antibody assays, and RSV and RV were tested by polymerase chain reaction (PCR). In 2010, 49 cases and 60 population controls attended a follow-up study, which included spirometry with bronchodilation test and fractionally exhaled nitric oxide (FENO ) measurements. Results Current asthma was present in 64% of the cases with RV-induced wheezing (OR 17.0 [95%CI 3.9-75.3] vs controls), in 43% of the cases with RSV-induced wheezing episode (6.1 [1.5-24.9] vs controls), and in 12% of the controls. The RV group showed significantly higher mean FENO values than the RSV group and controls. RV-positive cases had lower MEF50 before bronchodilation and higher MEF50, FEV1, and FEV1/FVC bronchodilation responses than controls. RSV-positive cases had lower FVC than controls before bronchodilation. Conclusion Cases with RV- and RSV-induced early-childhood wheezing had increased risk for asthma in adulthood, and RV-positive cases had significantly higher FENO values than RSV-positive cases and controls. Compared to controls, RV-positive cases showed more bronchial reactivity, and RSV-positive cases showed lower FVC before bronchodilation in lung function testing. Clinical relevance Children with RV- or RSV-induced wheezing in early childhood have an increased risk for asthma and lung function abnormalities in adulthood.