[1] Tech Univ Munich, Epidemiol, Dept Sport & Hlth Sci, Georg Brauchle Ring 56, D-80992 Munich, Germany
[2] Deutsch Jugendinst eV, Dept Families & Family Policies, German Youth Inst, Nockherstr 2, D-81541 Munich, Germany
[3] Ludwig Maximilians Univ Munchen, IBE Inst Med Informat Proc Biometry & Epidemiol, Marchioninistr 15, D-81377 Munich, Germany
[4] Univ Manchester, PSSRU, Div Populat Hlth Hlth Serv Res & Primary Care, Sch Hlth Sci, 46 Grafton St, Manchester M13 9NT, Lancs, England