Funding for this research was provided by:
Text and Data Mining valid from 2020-01-11
Received: 17 October 2019
Accepted: 30 December 2019
First Online: 11 January 2020
Ethics approval and consent to participate
: The study was approved by the Ethics Board at Lund University (LU 443–99, revised 2009). All families had given verbal consent to use data for research before inclusion in the CPUP register. Verbal consent is sufficient for participation in the Swedish national quality registers and the ethics committee approved the method of using verbal consent in this study.Permission to extract data from the CPUP register was obtained from the register owner.
: Not applicable.
: The authors declare that they have no competing interests.