Text and Data Mining valid from 2019-04-10
Received: 7 November 2018
Revised: 18 March 2019
Accepted: 19 March 2019
First Online: 10 April 2019
: The authors declare no competing interests.
: The study was approved by the Regional Committee on Health Research Ethics (The Capital Region of Denmark), approval number H-16049387, and study was performed in accordance with the Declaration of Helsinki.
: The dataset used and analysed during the current study is available from the corresponding author on reasonable request.
: This work is published under the standard license to publish agreement. After 12 months the work will become freely available and the license terms will switch to a Creative Commons Attribution 4.0 International (CC BY 4.0).