Overweight negatively affects pediatric respiratory function. In this study, we evaluate if overweight is associated with more severe bronchiolitis in hospitalized infants.


This retrospective cohort study analyzed infants aged 30 to 365 days hospitalized for bronchiolitis from September 2019 to April 2020. Exclusion criteria included known risk factors for severe bronchiolitis, asthma treatment, or bacterial pneumonia. Weight-for-length z-score was categorized per the World Health Organization’s growth assessments as overweight (z-score >2), underweight (z-score <−2), and standard weight (between −2 and ≤2). Primary outcomes included respiratory support, ICU stay, and local bronchiolitis score. Secondary outcomes included supplemental interventions.


After exclusion criteria, 385 of 644 infants were categorized as overweight (n = 24), standard (n = 335), or underweight (n = 26). There were differences in need for respiratory support (overweight, 100%; standard weight, 81.8%; underweight, 76.9%; P = .03), highest support of high-flow nasal cannula (overweight, 75%; standard weight, 48%; underweight, 42%; P = .03), admission to ICU (overweight, 54.2%; standard weight, 21.5%; underweight, 34.7%; P < .001), and median bronchiolitis score (overweight, 8 [interquartile range 5–10]; standard weight, 4 [3–7]; underweight, 4 [3–7]; P = .01). Findings remained significant after age adjustments. Additionally, overweight experienced higher frequency of certain treatments.


This study suggests overweight is associated with more severe bronchiolitis in hospitalized infants supported by increased respiratory support level, bronchiolitis scores, and interventions. Higher need for ICU admission may be related to high-flow nasal cannula limitations on the acute care floor.

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