1. Department of Pediatrics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
2. Department of Physical & Rehabilitation Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
3. Department of Biostatistics, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea