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Published on: August 7, 2017
Modifiable environmental factors predispose term infants to bronchiolitis but bronchiolitis itself predisposes to
Antonella Frassanito1, Raffaella Nenna1, Serena Arima2
1Department of Maternal Infantile and Urological Sciences, Sapienza University of Rome, Rome, Italy.
Insights
Viral bronchiolitis in infants is linked to environmental factors like tobacco smoke (risk) and breastfeeding (protection). Bronchiolitis significantly increases the risk of developing childhood wheezing and asthma.
Area of Science:
- Pediatrics
- Respiratory Medicine
- Epidemiology
Background:
- Viral bronchiolitis is a common infant respiratory infection.
- Environmental and genetic factors influence respiratory infections.
Purpose of the Study:
- Analyze risk factors for infant bronchiolitis.
- Investigate predisposing factors for transient wheezing and asthma post-bronchiolitis hospitalization.
- Compare outcomes with healthy controls over a 6-year follow-up.
Main Methods:
- Enrolled 645 infants hospitalized with bronchiolitis.
- Collected demographic and clinical data via questionnaire.
- Assessed 370 cases and 183 controls at age 6 for asthma (questionnaire, prick test, spirometry).
Main Results:
- Breastfeeding was protective (OR: 0.3), tobacco smoke a risk factor (OR: 2.1) for bronchiolitis.
- Bronchiolitis increased risk of transient wheezing (OR: 12.9) and asthma (OR: 4.6) at 6 years.
- Positive family history of atopy increased asthma risk (OR: 3.1); asthmatic children showed lower lung function and more positive skin prick tests.
Conclusions:
- Environmental factors like tobacco smoke and breastfeeding significantly influence bronchiolitis risk.
- Infant bronchiolitis is a major risk factor for developing preschool wheezing and asthma.
- Early life respiratory infections require continued monitoring for long-term respiratory health.
Introduction:
Viral bronchiolitis is a common lower respiratory tract infection in infants. Environmental and genetic factors can favor respiratory tract infections.
Aim:
The aim of this study is to analyze risk factors for bronchiolitis and to investigate the predisposing factors for developing transient wheezing and asthma through a 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 the structured questionnaire, for prick test and for spirometry, and were classified to asthmatic, transient wheezing, and no wheezing/no asthma.
Results:
Breastfeeding was an independent protective factor (odds ratio [OR]: 0.3, 95% confidence interval [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). Analyzing follow-up, bronchiolitis increased the risk of developing transient wheezing by 12.9 (95% CI: 6.3-26.1, p < 0.001) and of developing asthma by 4.6 (95% CI: 1.9-10.7, p < 0.001). A positive family history of atopy increased the risk of developing asthma by 3.1 (95% CI: 1.4-6.7, p = 0.005). Asthmatic patients had a lower % FEV1, a lower % flow-volume curve (FVC), and a lower FEV1/FVC value, 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.
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