Funding for this research was provided by:
Reumatikerförbundet (R-657931, R-744331, R-848441)
Received: 15 January 2021
Accepted: 25 May 2021
First Online: 10 June 2021
: The study was approved by the regional ethics committee in Uppsala County (Dnr 2016/263) and got additional approval from the Swedish Ethical Review Authority (Dnr 2020–01494). Verbal informed consent was obtained from all parents and children. Written informed consent was obtained from all parents and from children aged twelve years or older. The study was conducted in accordance with the Helsinki Declaration.
: Not applicable; no individual data was displayed.
: The author declares no conflicts of interest.