Funding for this research was provided by:
Klaus-Tschira-Stiftung (not applicable)
AOK Baden-Württemberg (not applicable)
Received: 30 May 2019
Accepted: 10 March 2020
First Online: 30 March 2020
Ethics approval and consent to participate
: The study was performed in accordance with the Declaration of Helsinki. Ethical approval was obtained from the Ethics Committee of the Medical Faculty of Heidelberg University (number S-647/2013). Since all data was collected anonymously, it was not necessary to obtain written informed consent. However, participants were informed that by returning the questionnaire they agree that their data will be analysed and published anonymously.
: Not applicable.
: The authors declare that they have no competing interests.