1 Department of General Medicine and Primary Care, University of Tsukuba Hospital, Ibaraki, Japan.
2 Department of Medical Education Studies, International Research Center for Medical Education, Graduate School of Medicine, The University of Tokyo, Japan.
3 Department of Internal Medicine, Tokatsu Hospital, Chiba, Japan.
4 Department of Endocrinology and Metabolism, TMG Asaka Medical Center, Saimata, Japan.