Received: 2 September 2019
Accepted: 16 January 2020
First Online: 12 February 2020
Ethics approval and consent to participate
: The ethical committee that approved the study was the Ethical Review Board in Stockholm (Dnr 2010/1563–31/1). Approval was also granted from the Swedish Data Inspection Board, a national agency that serves as an institutional review board for studies using database linkage. This study used anonymized data from Swedish national registers and thus informed consent could not be obtained.
: Not applicable.
: The authors declare that they have no competing interests.