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 ) <0.25, and skin barrier impairment as a high TEWL >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.

Maternal use of snus as smokeless tobacco in pregnancy and infant lung function.

Background: Smoking in pregnancy has detrimental effects on infant respiratory health, while the effects of other nicotine-containing products on infant lung function are unclear. We aimed to explore if smokeless tobacco such as snus used in pregnancy increased the risk of lower lung function in infancy and if the associations differed by sex. Methods: From the Scandinavian population-based Preventing Atopic Dermatitis and ALLergies in Children birth cohort, we included 1163 infants with available tidal flow-volume measurements at 3 months of age and maternal self-reported use of nicotine-containing products in pregnancy. The risk of a ratio of time to peak tidal expiratory flow to total expiratory time <25th percentile by any nicotine exposure, snus exclusively and cigarette smoking with or without other nicotine-containing products was explored by regression analyses adjusting for maternal age, education and asthma. Results: Overall 120 out of 1163 (10.3%) infants were exposed to any nicotine in utero, 71 out of 120 by snus exclusively and 49 out of 120 by smoking, with six also exposed to snus. By pregnancy week 6, 85.8% of mothers reported stopping nicotine use. The risk of lower lung function was higher in children exposed in utero to nicotine-containing products with an odds ratio (OR) of 1.63 (95% confidence interval (CI) 1.02-2.59) with a similar tendency for snus exclusively (OR 1.55, 95% CI 0.88-2.71) and smoking (OR 1.79, 0.84-3.84). Effect estimates were similar after adjusting for covariates. No differences of the effect by sex were observed. Conclusion: Our study suggests that in utero exposure to not only cigarettes, but also snus, may negatively affect infant lung function.