[1] Natl Hosp Norway, Oslo Univ Hosp, Dept Transplant Med, N-0027 Oslo, Norway
[2] St Olavs Univ Hosp, Dept Nephrol, Trondheim, Norway
[3] Norwegian Univ Sci & Technol, Fac Med, Dept Canc Res & Mol Med, N-7034 Trondheim, Norway
[4] Oslo Univ Hosp, Dept Transplant Med, Oslo, Norway
[5] Oslo Univ Hosp, Dept Prevent Med, Oslo, Norway
[6] Leiden Univ, Med Ctr, Dept Clin Epidemiol, Leiden, Netherlands