Text and Data Mining valid from 2019-04-10
Received: 30 January 2019
Accepted: 2 April 2019
First Online: 10 April 2019
Compliance with ethical standards
: The authors report no conflicts of interest in this work.
: This study has been approved by The Data Protection Agency (Project no. 704775 at Statistics Denmark). No approval from The Danish Research Ethics Committees for The Capital Region was needed since only national registry data have been used.
: As this is a registry study based on national registers no informed consent exists.