1. Department of Pediatrics, Aiiku Hospital, Minato, Tokyo, Japan;
2. Department of Pediatrics, Jichi Medical University, Shimotsuke, Tochigi, Japan;
3. Department of Epidemiology and Biostatistics, Translational Medical Center, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan;
4. Department of Neonatology, Maternal and Perinatal Center, Tokyo Women’s Medical University, Shinjuku, Tokyo, Japan; and
5. Department of Neonatology, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Osaka, Japan