[1] Charite, Pediat Pneumol & Immunol, D-13353 Berlin, Germany
[2] Laltrastatist Srl, Consultancy & Training, Biostat Off, Rome, Italy
[3] Tech Univ Munich, Pediat, D-80290 Munich, Germany
[4] St Josefs Hosp, Pediat St Hedwig, Freiburg, Germany
[5] Johannes Gutenberg Univ Mainz, Med Ctr, Pediat & Adolescent Med, D-55122 Mainz, Germany
[6] Univ Dusseldorf, Pediat Cardiol & Pneumol, Dusseldorf, Germany
[7] Altonaer Kinderkrankenhaus, Paediat Pneumol & Immunol, Hamburg, Germany
[8] Charite, Inst Social Med Epidemiol & Hlth Econ, D-13353 Berlin, Germany
[9] Univ Wurzburg, Inst Clin Epidemiol & Biometry, D-97070 Wurzburg, Germany
[10] Med Univ Vienna, Ctr Pathophysiol Infectiol & Immunol, Div Immunopathol, Dept Pathophysiol & Allergy Res, Vienna, Austria