[1] Univ Oslo, Oslo Univ Hosp, Dept Dermatol, Fac Med,Rikshosp, NO-0027 Oslo, Norway
[2] Univ Oslo, Inst Gen Practice & Community Med, NO-0027 Oslo, Norway
[3] Univ Oslo, Inst Basic Med Sci, Dept Biostat, NO-0027 Oslo, Norway
[4] Tibet Univ, Coll Med, Lhasa, Tibet, Peoples R China
[5] Univ Oslo, Div Mental Hlth & Addict, NO-0027 Oslo, Norway
[6] Hosp Trust Innlandet, Brumunddal, Norway