Article History
Received: 31 August 2017
Accepted: 16 April 2018
First Online: 23 April 2018
Authors’ information
: RS; DDS, PhD. FS; Cand Med, Specialist in Gastroenerology. LS; Professor, Biostatistics. HN; DDS, PhD. Head of the TAKO-centre.
: The study protocol was approved by the Regional Committee for Medical Research Ethics, South-East Norway. Ref nr; 2013/1021.
: Informed consent was obtained from all participants. When participants were under 18 years of age or had a legal guardian, informed consent was obtained from the parent or guardian as appropriate.
: The authors declare that they have no competing interests.
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