Urban Dust Microbiome: Impact on Later Atopy and Wheezing

Abstract

INTRODUCTION: Investigations in urban areas have just begun to explore how the indoor dust microbiome may affect the pathogenesis of asthma and allery. We aimed to investigate the early fungal and bacterial microbiome in house dust with allergic sensitization and wheezing later in childhood. METHODS: Individual dust samples from 189 homes of the LISAplus birth cohort study were collected shortly after birth from living room floors and profiled for fungal and bacterial microbiome. Fungal and bacterial diversity was assessed with terminal restriction fragment length polymorphism (tRFLP) and defined by the Simpson diversity index. Information on wheezing outcomes and co-variates until the age of 10 years was obtained by parental questionnaires. Information on specific allergic sensitization was available at 6 and 10 years. Logistic regression and General Estimation Equation (GEE) models were used to examine the relationship between microbial diversity and health outcomes. RESULTS: Logistic regression analyses revealed a significantly reduced risk of developing sensitization to aero-allergens at 6 years and ever wheezing until the age of 10 years for exposure to higher fungal diversity (adjusted Odds Ratio aOR (95%CI): 0.26 (0.10-0.70)), and 0.42 (0.18-0.96), respectively), in adjusted analyses. The associations were attenuated for the longitudinal analyses (GEE) until the age of 10 years. There was no association between higher exposure to bacterial diversity and the tested health outcomes. CONCLUSION: Higher early exposure to fungal diversity might help to prevent from developing sensitization to aero-allergens in early childhood, but the reasons for attenuated effects in later childhood require further prospective studies.