Funding for this research was provided by:
Received: 10 March 2017
Accepted: 28 July 2017
First Online: 24 August 2017
Change Date: 21 May 2021
Change Type: Correction
Change Details: A Correction to this paper has been published:
Change Details: https://doi.org/10.1186/S40168-021-01094-X
Ethics approval and consent to participate
: This study was approved by the Regional Committee for Medical and Health Research Ethics for Central Norway (ref: 120-2000 and 2014/1796/REK midt) and the Norwegian Data Inspectorate (ref: 2003/953-3 KBE/-). At least one of each child’s parent was informed and signed an informed consent form.
: Not applicable.
: The authors declare that they have no competing interests.
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