Document is current

Article History

Received: 12 April 2017

Accepted: 26 March 2018

First Online: 10 April 2018

Ethics approval and consent to participate

: The study has been approved by The Norwegian Data Protection Authority and REC - the Regional Committees for Medical and Health Research Ethics in Norway (REC). Study participation was voluntary. The TOPP study started in 1992/1993 when written consent in research studies was not a requirement. However, in later years, REC has reviewed all information given to participants and concluded that the study fulfils essential requirements for informed consent. The information spans oral and written information the parents and their children have been given both before and after the data collections about topics and results for current and future research, the confidentiality of the participants, the possibility to skip questions, and the right to withdraw from the study at any point. The children were invited through their mothers, who were given questionnaire surveys and separate response envelopes for themselves and their children.

: Not applicable.

: The authors declare that they have no competing interests.

: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.