Funding for this research was provided by:
Norges Forskningsråd (260453/H10)
Received: 27 January 2020
Accepted: 9 June 2020
First Online: 16 June 2020
Compliance with ethical standards
: The present study was funded by The Research Council of Norway. None of authors had a financial relationship with the funding organization. The authors declare that they have no other conflict of interest.
: Access to data for this study has been approved by the Regional Ethics Committee South East Norway (ref: 2013/1620) and the owners of the respective registers.