[1] Innlandet Hosp Trust, Dept Internal Med, N-2618 Lillehammer, Norway
[2] Rikshosp Univ Hosp, Dept Nephrol, Oslo, Norway
[3] Univ Hosp N Norway, Inst Clin, Tromso, Norway
[4] Univ Tromso, Inst Clin, N-9001 Tromso, Norway
[5] Univ Tromso, Inst Community Med, N-9001 Tromso, Norway
[6] Univ Hosp N Norway, Dept Nephrol, Tromso, Norway
[7] Univ Hosp N Norway, Clin Res Ctr, Tromso, Norway