Subjects and Protocol
A total of 620 fifth- and sixth-grade elementary school students (10–12 years old) who participated in the Seongnam Atopy Project (SAP) 2017 cohort were enrolled. This study was sponsored by the Seongnam City Government for the prevention and education of allergic diseases in Korean children and was conducted between January 2017 and October 2017.12
Demographic data were collected, and questionnaires completed by the parents were used to record symptoms of the children during the previous 12 months (wheezing, nasal symptoms, and eczema), based on the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire.13. Urine samples were collected in sterile cups and stored at −70°C for up to 3 months before analysis. Blood samples were stored at −70°C until determination of the levels of serum periostin, serum YKL-40, and total and allergen-specific immunoglobulin (Ig) E. FeNO levels were measured by a physician and impulse oscillometry (IOS) was performed by a well-trained technician. The study protocol was approved by the appropriate Institutional Review Board of CHA University (2017-04-049), and written informed consent documents were obtained from all parents or guardians of participating children.