Study population
In this study, a total of 1,797 children aged 9–12 years were recruited
from Seoul and Jeongeup cities in Korea. Of the total children
recruited, 351 who did not answer questions related to AR in the
questionnaire were excluded from the analysis. Current AR patients were
defined as children who were diagnosed with AR by the physician and had
AR symptoms during the last 12 months based on the questionnaire. This
study was conducted with approval from the institutional review boards
of Hallym University and University of Ulsan College of Medicine and the
principals of the children’s school (IRB number: 2008-0208).