1. School of Health Sciences, Shinshu University School of Medicine, Matsumoto 390-8621, Japan
2. Department of Pediatrics, Shinshu University School of Medicine, Matsumoto 390-8621, Japan
3. Center for Perinatal, Pediatric
4. Department of Preventive Medicine and Public Health, Shinshu University School of Medicine, Matsumoto 390-8621, Japan