Eun LeeJi Won KwonHyo Bin KimHo Sung YuMi Jin KangKyungmo HongSong I. YangYoung Ho JungSeung Hwa LeeKil Young ChoiHye Lim ShinSeo Ah HongHyung Young KimJu Hee SeoByoung Ju KimSo Yeon LeeDae Jin SongWoo Kyung KimGwang Cheon JangJung Yeon ShimSoo Jong HongUniversity of Ulsan, College of MedicineSeoul National University Bundang HospitalInje University Paik HospitalGoucher CollegeMahidol UniversityKosin University, College of MedicineKorea Cancer Center HospitalHallym UniversityKorea University Medical CenterNational Health Insurance Cooperation Ilsan HospitalSungKyunKwan University, School of Medicine2018-11-092018-11-092014-01-01Allergy, Asthma and Immunology Research. Vol.7, No.2 (2014), 167-17420927363209273552-s2.0-84937834967https://repository.li.mahidol.ac.th/handle/123456789/34112© Copyright The Korean Academy of Asthma, Allergy and Clinical Immunology. The complex interplay between environmental and genetic factors plays an important role in the development of asthma. Several studies have yielded conflicting results regarding the 2 asthma-related risk factors: antibiotic usage during infancy and/or a history of bronchiolitis during early life and the development of asthma. In addition to these risk factors, we also explored the effects of Toll-like receptor 4 (TLR4) polymorphism on the development of childhood asthma. Methods: This cross-sectional study involved 7,389 middle school students who were from 8 areas of Seoul, Korea, and completed the International Study of Asthma and Allergies in Childhood questionnaire. The TLR4 polymorphism rs1927911 was genotyped in 1,395 middle school students from two areas using the TaqMan assay. Results: Bronchiolitis in the first 2 years of life, antibiotic exposure during the first year of life, and parental history of asthma were independent risk factors for the development of asthma. When combined, antibiotic use and a history of bronchiolitis increased the risk of asthma (adjusted odds ratio [aOR]: 4.64, 95% confidence interval [CI]: 3.09-6.97, P value for interaction=0.02). In subjects with CC genotype of TLR4, antibiotic exposure and a history of bronchiolitis during infancy, the risk of asthma was increased, compared to subjects without these risk factors (aOR: 5.72, 95% CI: 1.74-18.87). Conclusions: Early-life antibiotic exposures and a history of bronchiolitis are risk factors for asthma in young adolescents. Polymorphisms of TLR4 modified the influence of these environmental factors. Reducing antibiotic exposure and preventing bronchiolitis during infancy may prevent the development of asthma, especially in genetically susceptible subjects.Mahidol UniversityImmunology and MicrobiologyMedicineArticleSCOPUS10.4168/aair.2015.7.2.167