Allergic Sensitization, Respiratory Infections, and Subsequent Lung Function in Preschool Children

Do allergic sensitization and recurrent (≥ 2) respiratory tract infection (RTI) in the first year of life have adverse effects on lung function at age 4 years?

Data were from the Barwon Infant Study, a birth cohort of 1074 infants from the Barwon region of Victoria, Australia. Allergic sensitization at age 1 year was assessed by skin prick testing to food and aeroallergens, recurrent RTI between age 4 weeks and 1 year by parent-reported episodes of cold and flu with cough, and lung function at age 4 years by nitrogen multiple breath washout (N₂MBW). Outcomes were lung clearance index (LCI_2.5), functional residual capacity, and acinar and conductive ventilation heterogeneity. Differences in mean or median outcomes between allergic sensitization and recurrent RTI groups were estimated using regression, with adjustment for confounding factors including lung function in early infancy.

N₂MBW data were available in 284 individuals. Aeroallergen sensitization was associated with higher (worse) average LCI_2.5 compared with no aeroallergen sensitization (mean difference [MD], 95% confidence interval [CI]: 0.57, [0.28, 0.86]). This effect was stronger among infants who experienced recurrent RTI (MD, 95% CI: 0.56, [0.24, 0.87]). There was no evidence of associations between food sensitization and lung function, or recurrent RTIs alone and lung function (MD, 95% CI for LCI_2.5: 0.00, [-0.19, 0.20]).

Aeroallergen sensitization at 1 year of age may have an adverse effect on lung function at age 4 years, with this effect being stronger among children with recurrent RTI.