[1] Univ Hosp Jena, Dept Pediat, Jena, Germany
[2] Univ Ulm, Dept Epidemiol, D-89069 Ulm, Germany
[3] Univ Hosp Freiburg, Dept Pediat, Freiburg, Germany
[4] Univ Childrens Hosp, Munich, Germany
[5] Univ Leipzig, Univ Hosp Children & Adolescents, D-04109 Leipzig, Germany
[6] Univ Hosp Homburg, Dept Pediat, Homburg, Germany
[7] Charite, Berlin, Germany
[8] Med Univ Vienna, Dept Pediat & Adolescent Med, Vienna, Austria