1. Paediatric Research Center, New Children’s Hospital, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
2. Primary Health Care Unit, Kuopio University Hospital, Kuopio, Finland
3. Folkhälsan Research Center, Helsinki, Finland
4. Helsinki University Central Hospital, HUS Inflammation Center, Rheumatology and University of Helsinki, Finland
5. Department of Paediatrics, Aarhus University Hospital, Aarhus, Denmark