[1] Univ Cologne, Inst Nursing Sci, Fac Med, Cologne, Germany
[2] Univ Cologne, Univ Hosp Cologne, Cologne, Germany
[3] Deutsch Zentrum Neurodegenerat Erkrankungen DZNE, Witten, Germany
[4] Witten Herdecke Univ, Fac Hlth, Sch Nursing Sci, Witten, Germany
[5] Univ Lubeck, Inst Social Med & Epidemiol, Nursing Res Grp, Lubeck, Germany
[6] Martin Luther Univ Halle Wittenberg, Inst Hlth & Nursing Sci, Med Fac, Halle, Saale, Germany
[7] Heinrich Heine Univ Dusseldorf, Med Fac, Inst Hlth Serv Res & Hlth Econ, Ctr Hlth & Soc, Dusseldorf, Germany
[8] Heinrich Heine Univ Dusseldorf, Univ Hosp Dusseldorf, Dusseldorf, Germany
[9] MediStatistica, Neuenrade, Germany