[1] Karolinska Univ Hosp, Dept Med, Stockholm, Sweden
[2] Karolinska Inst, Clin Epidemiol Unit, Stockholm, Sweden
[3] Orebro Univ Hosp, Dept Pediat, Orebro, Sweden
[4] Mayo Clin, Coll Med, Div Gastroenterol & Hepatol, Dept Med, Rochester, MN USA
[5] Mayo Clin, Coll Med, Div Gastroenterol & Hepatol, Dept Immunol, Rochester, MN USA
[6] Karolinska Inst, Ctr Family & Community Med, Dept NVS, Stockholm, Sweden
[7] Univ Newcastle, Fac Hlth, Newcastle, NSW 2300, Australia
[8] Inst Pathol, Bayreuth, Germany
[9] Primary Hlth Care Ctr Tornio, Tornio 95410, Finland
[10] Univ Oulu, Inst Hlth Sci, Oulu, Finland