Text and Data Mining valid from 2019-11-07
Received: 21 August 2019
Accepted: 22 October 2019
First Online: 7 November 2019
Ethics approval and consent to participate
: This study was approved by the local ethics committee. Written informed consent was obtained from all participants. The study protocol conforms to the ethical guidelines of the 1975 Declaration of Helsinki.
: Not applicable.
: The authors declare that they have no competing interests.