[1] Huddinge Univ Hosp, Karolinska Inst, Dept Surg, Arvid Wretlind Lab Metab Res, S-14186 Huddinge, Sweden
[2] Linkoping Univ, Univ Hosp, Dept Clin Chem, S-58185 Linkoping, Sweden
[3] Linkoping Univ, Univ Hosp, Dept Geriatr Med, S-58185 Linkoping, Sweden
[4] Creighton Univ, Sch Med, Dept Biomed Sci, Omaha, NE 68178 USA