Fatigue is not associated with vitamin D deficiency in inflammatory bowel disease patients
Svein Oskar Frigstad, Department of Medicine, Vestre Viken Bærum Hospital, Gjettum 1346, Norway
Svein Oskar Frigstad, Department of Research, Østfold Hospital Kalnes, Grålum 1714, Norway
Marte Lie Høivik, Bjørn Moum, Department of Gastroenterology, Oslo University Hospital, Oslo 0424, Norway
Jørgen Jahnsen, Department of Gastroenterology, Akershus University Hospital, Lørenskog 1478, Norway
Milada Cvancarova, Faculty of Health Sciences, Oslo Metropolitan University, Oslo 0130, Norway
Tore Grimstad, Department of Gastroenterology, Stavanger University Hospital, Stavanger 4068, Norway
Ingrid Prytz Berset, Department of Medicine, Ålesund Hospital Trust, Ålesund 6026, Norway
Gert Huppertz-Hauss, Department of Gastroenterology, Telemark Hospital Trust, Skien 3710, Norway
Øistein Hovde, Department of Medicine, Innlandet Hospital Trust, Gjøvik 2819, Norway
Tomm Bernklev, Department of Research and Development, Vestfold Hospital Trust, Tønsberg 3103, Norway
Lars-Petter Jelsness-Jørgensen, Department of Gastroenterology, Østfold Hospital Kalnes, Grålum 1714, Norway
Lars-Petter Jelsness-Jørgensen, Department of Health Sciences, Østfold University College, Halden 1757, Norway
Author contributions: Frigstad SO performed the study, analysed the data and wrote the paper; Høivik ML and Cvancarova M analyzed the data, contributed to the design of tables and writing of the paper; Jahnsen J performed the study, contributed to tables and writing of the paper; Grimstad T, Berset IP, Huppertz-Hauss G and Hovde Ø performed the study and contributed to writing of the paper; Bernklev T contributed to the design of the study and writing of the paper; Moum B contributed to the design of the study, performed the study and supervised the writing of the paper; Jelsness-Jørgensen LP designed, supervised and performed the study, contributed to analysing the data and revised the paper; all authors have approved the final manuscript.
Institutional review board statement: The Regional Committee for Medical and Health Research Ethics approved the study. The approval has been uploaded with the submission of the manuscript (2012/845/REK).
Informed consent statement: All the study participants gave written, informed consent before inclusion in the study, and the study was performed in accordance with the Declaration of Helsinki. The consent form that was used has been uploaded with the submission of the manuscript.
Conflict-of-interest statement: The authors declare no conflicts of interest.
Data sharing statement: No additional data are available.
STROBE statement: The guidelines of the STROBE statement have been adopted and a fulfilled version of the checklist has been attached with the submission of the manuscript.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Svein Oskar Frigstad, MD, Doctor, Research Fellow, Department of Research, Østfold Hospital Kalnes, Postboks 300, Grålum 1714, Norway. firstname.lastname@example.org
Telephone: +47-91508600 Fax: +47-69863285
Received: April 4, 2018
Peer-review started: April 4, 2018
First decision: May 30, 2018
Revised: June 17, 2018
Accepted: June 27, 2018
Article in press: June 27, 2018
Published online: August 7, 2018