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Article History

Received: 6 April 2017

Accepted: 20 June 2018

First Online: 18 July 2018

Ethics approval and consent to participate

: All subjects had been selected consecutively; written informed consent from participants, the ethical approval was obtained from the regional ethics committee in Göteborg, Sweden (697–11) and conducted according to the Declaration of Helsinki.

: Not applicable.

: The authors declare that they have no competing interests.

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