Received: 16 February 2021
Revised: 13 April 2021
Accepted: 27 April 2021
First Online: 18 May 2021
Compliance with ethical standards
: The authors declare no competing interests.
: All participants from Tromsø 4–7 provided written informed consent and the present study was approved by the Regional Ethics Committee for Medical Research (ref. 2016/758410).