Gene-environment interaction between Toll-like receptor 4 and mold exposure in the development of atopic dermatitis in preschool children

ABSTRACT

PURPOSE: Genetic factors and environmental exposures are recognized as important risk factors for atopic dermatitis (AD) in children. Inflammatory responses by molds can be mediated via Toll-like receptor 4 (TLR4). The aims of this study were to investigate mold as risk factor of AD and gene-environment interaction on AD in preschool children. METHODS: We undertook a cross-sectional survey with 986 preschool children. We investigated five mold exposure measures (dampness stain, dampness damage, visible mold, mold odor, and house repair). The TLR4 polymorphism (rs1927911) was genotyped by TaqMan assay. RESULTS: The prevalence of AD was as follows AD diagnosis by questionnaire, 35.1%; current AD (lifetime diagnosis together with symptoms in the last 12 months), 21.5%. When children with parental history of AD were exposed to mold odor during infancy and house repair during the last 12 months, the risk for current AD (adjusted odds ratio [aOR], 6.826; 95% confidence interval [CI], 2.511 to 18.554 vs. aOR, 6.143; 95% CI, 2.348 to 16.074) was further increased than only with parental history of AD. In children with the CC genotype of TLR4 polymorphism, the risk of AD was increased by mold exposure. CONCLUSION: This investigation identified that mold exposure is potential risk factor for AD in preschool children. Parental history of AD and mold exposure during infancy and the last 12 months had synergistic effect on high prevalence of AD. We identified that mold exposure and TLR4 polymorphism have an effect on the development of atopic dermatitis.