Funding for this research was provided by:
Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology
Norwegian National Research School in Population Based Epidemiology
Received: 11 January 2019
Accepted: 10 May 2019
First Online: 20 May 2019
Ethics approval and consent to participate
: All participants in the HUNT Study gave a written informed consent upon participation. This study was approved by the Regional Committee for Ethics and Medical Research (2014/1116/REK midt).
: Not applicable.
: The authors declare that they have no competing interests.
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