Funding for this research was provided by:
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (100014-134562)
Received: 28 August 2017
Accepted: 5 February 2018
First Online: 26 February 2018
Ethics approval and consent to participate
: The study was formally approved by the relevant Ethics Board (identifier 254/08) and research committee. The participants gave a written informed consent to take part in the trial and to publish. The trial was registered atExternalRef removed(identifier NCT01896024).
: All participants consented to their data being included in publications, provided that identifying information was not published.
: The authors declare that they have no competing interests.
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