Bacterial airway colonization in neonates reveals a specific childhood asthma endotype

Abstract

<b>Background:</b> We previously showed an association between neonatal bacterial airway colonization and increased risk of asthma in the first 5 years of life, suggesting an airway bacteria colonization-associated childhood asthma endotype. <b>Aims and objectives:</b> To study the long-term trajectory of the colonization-associated childhood asthma endotype. <b>Methods:</b> We investigated the association between airway colonization with S. pneumoniae, H. influenzae, and/or M. catarrhalis in one-month-old neonates from the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2000) mother-child cohort and development of asthma endpoints until age 18 years. Analyses were done with repeated measurement generalized estimating equations (GEE). <b>Results:</b> Neonatal airway colonization was present in 66 (21%) of 319 children and was associated with an overall increased risk of asthma (GEE adjusted odds ratio, 4.01 (95% CI, 1.76-9.12, p&lt;0.001)) and increased number of exacerbations the first 7 years of life (adjusted incidence rate ratio, 3.20 (95% CI, 1.38-7.44, 0&lt;0.01)), but not from age 7 to 18 years. In colonized children, blood eosinophils were increased from age 6 months to 12 years (GEE adjusted geometric mean ratio, 1.24 (95% CI, 1.06-1.44), p&lt;0.01), but not at age 18 years. There were no significant associations with lung function, bronchial reactivity, atopic dermatitis or other asthma and allergy-related endpoints. <b>Conclusions:</b> Neonatal airway colonization is associated with a particular endotype characterized by early-onset asthma, exacerbations, and elevated blood eosinophils, which is most prominent in early childhood, thereafter&nbsp;diminishing, and is no longer evident by age 18 years.