Funding for this research was provided by:
Konung Gistaf V:s 80-years Fund
Swedish Rheumatism Association
Medicinska Forskningsrådet (K2013-52X-20307-07-3)
the Västerbotten county council
Received: 3 January 2018
Accepted: 3 August 2018
First Online: 12 September 2018
Ethics approval and consent to participate
: The participants gave their written informed consent and the Regional Ethics Committee at Umeå University approved the study (reference number 2013/347–31).
: Not applicable.
: The authors declare that they have no competing interests.
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