Funding for this research was provided by:
Bundesministerium für Bildung und Forschung (01GL1708A and 01GL1708B)
Received: 7 August 2019
Accepted: 25 December 2020
First Online: 13 January 2021
Ethics approval and consent to participate
: The study protocol, informed consent forms, participant information materials and questionnaires / structured interviews were approved by the Ethical Review Committee of the Medical Department of the Philipps-University of Marburg (Ref: 208/17) and by the Ethics Committee of Witten/Herdecke University (Ref: 71/2018).
: Not applicable.
: Ellen Freiberger is an Associate Editor for BMC Geriatrics.