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Published on: November 10, 2023
Risk factors for irreversible airway obstruction after infant bronchiolitis
Riikka Riikonen1, Matti Korppi1, Sari Törmänen1
1Center for Child Health Research, Tampere University and University Hospital, Tampere, Finland.
Insights
Early asthma diagnosis and poor preschool lung function increase the risk of irreversible airway obstruction after infant bronchiolitis. Toll-like receptor 4 (TLR4) gene variants may offer protection against this condition.
Area of Science:
- Pediatric Pulmonology
- Environmental Health
- Genetics
Background:
- Childhood environmental factors influence irreversible airway obstruction.
- Infant bronchiolitis is a key concern for long-term respiratory health.
- Identifying early risk factors is crucial for preventing adolescent airway obstruction.
Purpose of the Study:
- To evaluate early-life and preschool risk factors for adolescent irreversible airway obstruction following infant bronchiolitis.
- To investigate the association between asthma diagnosis, lung function, and TLR4 genotype with irreversible airway obstruction.
Main Methods:
- Secondary analysis of a prospective post-bronchiolitis cohort.
- Risk factor data collected during hospitalization and at ages 5-7 and 10-13 years.
- Lung function assessed using impulse oscillometry (ages 5-7) and spirometry (ages 10-13).
Main Results:
- Early asthma diagnosis (<12 months) strongly predicted irreversible airway obstruction at 10-13 years.
- Impulse oscillometry findings at preschool age (5-7 years) predicted later obstruction.
- Toll-like receptor 4 (TLR4) rs4986790 variant showed a potential protective effect, though not significant after adjustments.
Conclusions:
- Infant bronchiolitis followed by early asthma and impaired preschool lung function elevates the risk of irreversible airway obstruction.
- TLR4 rs4986790 polymorphism may play a protective role in the development of post-bronchiolitis airway obstruction.
Background:
Increasing evidence shows that environmental factors in childhood play a role in development of irreversible airway obstruction. We evaluated early-life and preschool-age risk factors for irreversible airway obstruction in adolescence after bronchiolitis in infancy.
Methods:
This study is a secondary analysis of data collected during prospective long-term follow-up of our post-bronchiolitis cohort. Risk factor data were collected during hospitalisation and on follow-up visits at 5-7 and 10-13 years of ages. Lung function was measured from 103 participants with impulse oscillometry at 5-7 years of age and from 89 participants with flow-volume spirometry at 10-13 years of age.
Results:
Asthma diagnosis at <12 months of age showed a significant association with irreversible airway obstruction at 10-13 years of age independently from current asthma. Irreversible airway obstruction was less frequent in children with variant than wild genotype of the Toll-like receptor 4(TLR4) rs4986790, but the significance was lost in logistic regression adjusted for current asthma and weight status. Higher post-bronchodilator respiratory system resistance at 5 Hz and lower baseline and post-bronchodilator reactance at 5 Hz by impulse oscillometry at 5-7 years of age were associated with irreversible airway obstruction at 10-13 years of age.
Conclusion:
Asthma diagnosis during the first living year and worse lung function at preschool age increased the risk for irreversible airway obstruction at 10-13 years of age after bronchiolitis. TLR4 rs4986790 polymorphism may be protective for development of irreversible airway obstruction after bronchiolitis.
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