Funding for this research was provided by:
Throne Holst Nutrition Research Foundation
The Research Council of Norway (Project number 228452)
Received: 6 May 2019
Accepted: 2 August 2019
First Online: 13 August 2019
Ethics approval and consent to participate
: This study was conducted according to the guidelines laid down in the Declaration of Helsinki, and the Norwegian Center for Research Data approved all procedures involving human subjects. Parental written consent was obtained for 633 children.
: Not applicable.
: The authors declare they have no competing interests.