Ethical approval
This study was conducted with approval from the institutional review
boards of Hallym University and the University of Ulsan College of
Medicine and the principals of the children’s school (IRB number:
2008-0208). Written informed consent was obtained from the parents of
all the children prior to study initiation. The obtainment of consent
was confirmed by the IRB.
Authorship: Choi EJ, Lee SY, and Hong SJ designed and wrote the
manuscript and performed the analyses. Kun Baek Song, Eun Young Baek,
Min Ji Park, Jisun Yoon, Sungsu Jung, Si Hyeon Lee, Mi-Jin Kang, Hea
Young Oh, and Kang Seo Park participated in the collection, analysis,
and interpretation of the data. Hong SJ and Lee SY supervised the
execution of the study.