[1] Tonan Hosp, Dept Internal Med, Fed Natl Publ Serv Personnel Mutual Aid Assoc, Sapporo, Hokkaido 0600001, Japan
[2] Kanazawa Univ, Sch Med, Dept Internal Med 3, Kanazawa, Ishikawa 9208641, Japan
[3] Tonan Hosp, Dept Surg, Fed Natl Publ Serv Personnel Mutual Aid Assoc, Sapporo, Hokkaido 0600001, Japan
[4] Hokkaido Univ, Sch Med, Dept Internal Med 3, Sapporo, Hokkaido 0608638, Japan