Irreversible airway obstruction in adulthood after bronchiolitis in infancy: evidence from a 30-year follow-up study

Lower respiratory infections in infancy may be associated with lung function deficits in adulthood. Our aim was to evaluate lung function, with a special focus on irreversible airway obstruction, thirty years after bronchiolitis or pneumonia in infancy.

In 1981-1982, 83 children under two years of age were hospitalized for bronchiolitis and 44 for pneumonia at Kuopio University Hospital, Finland. In 2010, 47 bronchiolitis patients, 22 pneumonia patients and 138 controls attended the study, including spirometry before (pre-BD) and after bronchodilatation (post-BD). The measured indices were forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), that were presented as % of predicted value (FVC% and FEV1%). FEV1/FVC was presented as both absolute FVC/FEV1-ratio and % of predicted (FEV1/FVC%). Irreversible airway obstruction was defined as post-BD FEV1/FVC% below 88% of predicted (FEV1/FVC% <88%) according to Finnish reference values or FEV1/FVC-ratio below fifth percentile (FEV1/FVC <5th percentile), according to Global Lung Function Initiative reference values.

All lung function indices were lower in former bronchiolitis patients and pre- and post-BD FEV1% in pneumonia patients, compared to controls. 21% of bronchiolitis (OR, 95%CI; 5.59, 1.72-18.21) and 9% of pneumonia patients (2.24, 0.34-13.56) had FEV1/FVC% <88% compared to controls (4%). Likewise 7 (15%) of bronchiolitis (7.07, 1.33-37.22) and 1 (5%) of pneumonia patients (1.73, 0.12-24.77) had FEV1/FVC <5th percentile compared to controls 2 (1%).

Evidence of reduced lung function was present 30 years after hospitalization for bronchiolitis or pneumonia in infancy. Irreversible airway obstruction after severe bronchiolitis in infancy suggests permanent, structural alterations in airways.