This paper was originally published without acknowledging the contributions of the following three authors:
Anna Ekström, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
Elias Ingebrand, Department of Culture and Society, Linköping University, Linköping, Sweden
Christina Samuelsson, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
SD, MB, KL, AE and CS are responsible for the overall design of the study, and the development of instruments. SD, MB, KL, AE, CS and EI are responsible for the organisation of data collection. MBN and J-AS are responsible for the analysis and interpretation of the data and for the drafting of this article under the supervision of KL. SD and MB are responsible for revising this article for content and for getting it into a state ready for submission.
The paper has now been updated with the correct author information and this corrigendum published.