Christiansen, Solveig Glestad
Bretteville-Jensen, Anne Line
Article History
Received: 8 January 2018
Accepted: 29 May 2018
First Online: 22 June 2018
Ethics approval and consent to participate
: The study was approved by the Regional Ethical Committee on Ethics in Medical Research. Consent to participate was not necessary as we only use public register data.
: The authors declare that they have no competing interests.
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