1. From the Department of Hygiene and Preventive Medicine (GO, KM, TO, MN, NY, SY), School of Medicine, University of Tokyo: Department of Gastroenterology (KN), Women's Medical College: Department of Gastroenterology (KH), Toranomon General Hospital; Department of Gastroenterology (KK), Jichi Medical College; Laboratory of Food and Nutrition (BM), Toita Women's College Tokyo, Japan