Infant lung function and early skin barrier impairment in the development of asthma at age 3 years

Background Largely unexplored, we investigated if lower lung function, impaired skin barrier function by transepidermal water loss (TEWL), eczema, and filaggrin (FLG) mutations in infancy were associated with asthma in early childhood. Methods From the factorially designed randomized controlled intervention study PreventADALL, we evaluated 1337/2394 children from all randomization groups with information on asthma at age 3 years, and at age 3 months either lung function, TEWL, eczema, and/or FLG mutations. Lower lung function was defined as the time to peak tidal expiratory flow to expiratory time (tPTEF/tE) 9.50 g/m2/h. Eczema was clinically observed, and DNA genotyped for FLG mutations. Asthma was defined as asthma‐like symptoms (≥3 episodes of bronchial obstruction) between age 2–3 years as well as a history of doctor‐diagnosed asthma and/or asthma medication use. Associations were analyzed in logistic regression models, presented with adjusted ORs (aOR) and 95% confidence intervals (CI). Results Lower lung function and skin barrier impairment were associated with asthma in general; aOR (95% CI) 5.4 (2.1, 13.7) and 1.6 (1.1, 2.5), while eczema and FLG mutations were associated with asthma in children with atopic dermatitis or allergic sensitization only. Stratifying for sex, the risk of asthma was only increased in boys with lower lung function; aOR (95% CI) 7.7 (2.5, 23.6), and in girls with FLG mutations; aOR (95% CI) 3.5 (1.5, 8.2). Conclusion Lower lung function and impaired skin barrier function in infancy may increase the risk of asthma at age 3 years. In a large pediatric population from the factorially designed randomized controlled intervention study PreventADALL, we investigated if lower lung function, impaired skin barrier function by TEWL, eczema at age 3 months and FLG mutations were associated with asthma at age 3 years. Lower lung function and skin barrier impairment in infancy increased the risk of asthma in general. Stratifying for sex, the risk of asthma was only increased in boys with lower lung function. Eczema and FLG mutations were associated with asthma in children with AD or AS only.Abbreviations: AD, atopic dermatitis; AS, allergic sensitization; aOR, adjusted odds ratio; CI, confidence interval; FLG, filaggrin; PreventADALL, Preventing Atopic Dermatitis and ALLergies in children; TEWL, transepidermal water loss.