Bacterial colonisation of the airway in neonates and risk of asthma and allergy until age 18 years

Abstract

BackgroundWe previously showed an association between neonatal bacterial airway colonisation and increased risk of persistent wheeze/asthma until age 5 years. Here, we study the association with persistent wheeze/asthma and allergy-related traits until age 18 years.MethodsWe investigated the association between airway colonisation withStreptococcus pneumoniae,Moraxella catarrhalisand/orHaemophilus influenzaein 1-month-old neonates from the COPSAC2000mother–child cohort and the development of persistent wheeze/asthma and allergy-related traits longitudinally until age 18 years using generalised estimating equations. Replication was sought in the similarly designed COPSAC2010cohort of 700 children.ResultsNeonatal airway colonisation was present in 66 (21%) out of 319 children and was associated with a 4-fold increased risk of persistent wheeze/asthma (adjusted OR 4.01 (95% CI 1.76–9.12); p<0.001) until age 7 years, but not from age 7 to 18 years. Replication in the COPSAC2010cohort showed similar results using 16S data. Colonisation was associated with an increased number of exacerbations (adjusted incidence rate ratio 3.20 (95% CI 1.38–7.44); p<0.01) until age 7 years, but not from age 7 to 18 years. Colonisation was associated with increased levels of blood eosinophils (adjusted geometric mean ratio 1.24 (95% CI 1.06–1.44); p<0.01) and tumour necrosis factor (TNF)-α (adjusted geometric mean ratio 1.09 (95% CI 1.02–1.16); p=0.01) until age 12 years. There were no associations with lung function, bronchial reactivity, fractional exhaled nitric oxide, allergic sensitisation, total IgE or atopic dermatitis up to age 18 years.ConclusionsNeonatal airway colonisation was associated with early-onset persistent wheeze/asthma, exacerbations, elevated blood eosinophils and elevated TNF-α in blood, most prominent in early childhood, thereafter diminishing and no longer evident by age 18 years.