Funding for this research was provided by:
Det Norske Forskningsråd (273551)
TROND MOHN Foundation (BFS2018TMT10)
Text and Data Mining valid from 2020-02-05
Received: 10 October 2019
Accepted: 11 December 2019
First Online: 5 February 2020
Ethics approval and consent to participate
: The Ethics Committee was contacted in 2015, and no ethical approval was needed since this was then considered a quality control study. Written consent was obtained from all participants.
: Not applicable.
: Cecilie G Gjerde, Siddharth Shanbhag, Evelyn Neppelberg, Kamal Mustafa, and Harald Gjengedal declare that they have no competing interests.