1. Department of Pediatrics and Neonatology, Toyohashi Municipal Hospital, 50 Aza Hakken Nishi, Aotake-cho, Toyohashi 441-8570, Japan
2. Department of Pediatrics and Neonatology, Shizuoka Saiseikai General Hospital, Shizuoka 422-8527, Japan
3. Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
4. Center for Human Development and Family Science, Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho, Nagoya 467-8601, Japan