Acute Bronchiolitis in Young Children and Future Mental Health Outcome: A 15-Year National Population Study Regardless of Allergic Conditions.

Children hospitalized for acute bronchiolitis had a 20% increased risk of developing any mental health disorder compared to unexposed children.

• Adjusted hazard ratio (aHR) for any mental health disorder was 1.20 (95% CI, 1.16-1.23)
• Incidence rate was 187.9 per 10,000 person-years in the bronchiolitis cohort versus 153.9 per 10,000 person-years in the unexposed cohort
• Mean follow-up was 15 years
• Study included 25,550 children hospitalized for bronchiolitis compared to 102,220 matched unexposed children

Early-onset developmental disorders (before age 10) were significantly more common in children with prior bronchiolitis hospitalization.

• aHR for early-onset developmental disorders was 1.34 (95% CI, 1.26-1.43)
• Early-onset conditions were defined as those occurring before 10 years of age
• This represented a 34% increased risk compared to the unexposed cohort

Late-onset psychiatric disorders (after age 10) were also significantly elevated in children previously hospitalized for bronchiolitis.

• aHR for late-onset psychiatric disorders was 1.18 (95% CI, 1.15-1.22)
• Late-onset conditions were defined as those occurring after 10 years of age
• Children were followed until December 2021, allowing observation into adolescence and early adulthood

There was a progressive increase in risk for multiple mental health disorders among children hospitalized for bronchiolitis.

• A statistically significant dose-response relationship was observed for multiple mental health disorders (p < 0.01)
• 24 predefined mental health disorders were evaluated as primary outcomes
• Outcomes were categorized into early-onset and late-onset conditions

Asthma and atopic dermatitis did not significantly modify the association between bronchiolitis hospitalization and mental health outcomes.

• Interaction p-value for asthma was 0.77
• Interaction p-value for atopic dermatitis was 0.48
• Neither allergic condition significantly modified the risk of mental health disorders following bronchiolitis
• The modifying effects of both conditions were specifically evaluated as secondary analyses

This national population-based cohort study used data from the South Korean National Health Insurance Service covering nearly one million children born between 2002 and 2003.

• Total cohort included 985,957 children born between 2002 and 2003
• Children were followed until December 2021
• The median age at hospitalization for bronchiolitis was 8 months (IQR, 3-20 months)
• Hazard ratios were estimated using proportional hazards models adjusting for potential confounders
• Bronchiolitis-hospitalized children (n = 25,550) were compared to a matched unexposed cohort (n = 102,220)