Funding for this research was provided by:
AFA Försäkring (160138)
Received: 7 January 2020
Accepted: 18 August 2020
First Online: 27 August 2020
Ethics approval and consent to participate
: The study population was based on linkage of several national registers. Ethical vetting is always required when using sensitive register data in Sweden. The ethical vetting is performed by regional ethical review boards and the risk appraisal associated with the Law on Public Disclosure and Secrecy is done by data owners (authorities). The Regional Ethical Review Board can waive the requirement to consult in these type of large register studies, and for this project stated that the consent to participate was not applicable. Patient records/information were anonymized and de-identified prior to analysis by the authority, Statistics Sweden, which was responsible for data linkage. Researchers received de-identified data. According to these standards in Sweden this project has been evaluated and approved by the Regional Ethical Review Board of Karolinska Institutet, Stockholm, Sweden (Dnr: 2007/524–31, 2010/1346–32/5, Dnr: 2014/311–32 and 2017/128–32).
: Not applicable.