Text and Data Mining valid from 2019-11-08
Received: 11 March 2019
Accepted: 4 September 2019
First Online: 8 November 2019
Ethics approval and consent to participate
: The final revised version of the study protocol (version 3, dated 29 June 2018) and the informed consent form used in the study were assessed and approved by the ethics committee of the Medical University Hannover (7751_BO_S_2018). Written informed consent was obtained from every participant prior to registration.
: Not applicable
: The authors declare that they have no competing interests.