Received: 14 June 2018
Accepted: 24 January 2019
First Online: 8 February 2019
Ethics approval and consent to participate
: The study received ethical approval from the regional ethical review board in Linköping (# 2012/336–32). All participants were properly informed about all study procedures and they gave written informed consent to participate in the study. The study is conducted in accordance with the guidelines of the Declaration of Helsinki.
: Consent for publication is included in the informed written consent to participate in the study.
: The authors declare that they have no competing interests.
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