Ethical considerations
Ethical approval for the Fex‐Can Cohort and RCT study was obtained by the Regional Ethical Review Board in Stockholm, Sweden (Dnr: 2013/1746‐31/4; 2014/2244‐32;2015/2042‐32/4; 2017/916‐32; 2017/1416‐32).Individuals eligible for participation in the RCT received an information letter about the intervention and study procedures via postal mail. The letter further contained information about the voluntary nature of participation, and that participants could withdraw their consent at any time. Written informed consent was obtained from all participants. Data were processed according to the EU General Data Protection regulation (GDPR).