Funding for this research was provided by:
Research Council of Norway’s Center of Excellence scheme (262700)
Text and Data Mining valid from 2020-01-16
Received: 27 August 2019
Accepted: 2 January 2020
First Online: 16 January 2020
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: The study was approved by the Regional Committee for Medical and Health Research Ethics South East, Norway.
: Informed consent was not obtained from the individual participants included in the study, as data were obtained from nationwide health registries to which reporting is mandatory.