Introduction

viral bronchiolitis is a common lower respiratory tract infection in infants. Environmental and genetic factors can favour respiratory tract infections.

Aim

to analyse risk factors for bronchiolitis and to investigate the predisposing factors for developing transient wheezing and asthma through 6-year follow-up after hospitalization for bronchiolitis compared with a group of healthy controls that belonged to Piccolipiù cohort, who never had bronchiolitis.

Methods

we enrolled 645 infants hospitalized with bronchiolitis. A structured questionnaire was used to obtain demographic and clinical data. At 6 years of age, 370 cases and 183 controls were investigated for the presence of asthma by structured questionnaire, for prick test and for spirometry and classified in asthmatic, transient wheezing, no wheezing/no asthma.

Results

breastfeeding was an independent protective factor (OR 0.3, 95% CI 0.2-0.4, p<0.001) and tobacco smoke was a risk factor for the development of bronchiolitis (OR 2.1, 95% CI 1.4-3.1, p<0.001). Analysing follow-up, bronchiolitis increased the risk of developing transient wheezing by 12.9 (95%IC: 6.3-26.1, p<0.001) and of developing asthma by 4.6 (95%IC: 1.9-10.7, p<0.001). A positive family history of atopy increased the risk of developing asthma by 3.1 (95%IC 1.4-6.7, p=0.005). Asthmatic patients had a lower % FEV1, a lower % FVC and a lower FEV1/FVC values and they had more frequently positive skin prick test.

Conclusion

bronchiolitis is influenced by environmental factors: tobacco smoke increases its risk and breastfeeding is a protective factor. At the end of 6 years of follow-up, bronchiolitis is a significant risk factor to have pre-school wheezing and asthma.

This article is protected by copyright. All rights reserved.