Text and Data Mining valid from 2019-12-01
Received: 26 July 2018
Accepted: 6 November 2019
First Online: 2 December 2019
Ethics approval and consent to participate
: Ethical approval was obtained from the London Multicentre Research and Ethics Committee (MREC/01/2/91). Written informed consent was obtained from all individual participants included in the study.
: Not applicable.
: The authors declare that they have no competing interest.