[1] Univ Hosp Carl Gustav Carus, Inst & Outpatient Clin Pediat, Dresden, Germany
[2] Univ Hosp Carl Gustav Carus, Inst & Outpatient Clin Adolescent Med, Dresden, Germany
[3] Robert Koch Inst, Dept Epidemiol & Hlth Monitoring, Berlin, Germany
[4] John Radcliffe Hosp, Translat Gastroenterol Unit, Oxford OX3 9DU, England
[5] John Radcliffe Hosp, Dept Pediat, Oxford OX3 9DU, England
[6] Univ Giessen, Dept Gen Pediat & Neonatol, Ctr Pediat & Adolescent Care, D-35390 Giessen, Germany
[7] Robert Koch Inst, Dept Epidemiol & Hlth Monitoring, Epidemiol Lab, Berlin, Germany
[8] Univ Munich, Dr von Hauner Childrens Hosp, Munich, Germany