1. Department of Clinical Epidemiology, Translational Medical Center, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
2. Department of Neuropsychiatry, Hirosaki University School of Medicine, Hirosaki, Aomori, Japan
3. Department of Gastroenterology, Hirosaki University School of Medicine, Hirosaki, Aomori, Japan
4. Department of Social Medicine, Hirosaki University School of Medicine, Hirosaki, Aomori, Japan