Received: 14 November 2017
Accepted: 4 May 2018
First Online: 15 May 2018
Ethics approval and consent to participate
: The HaBIDS study was approved by the Ethics Committee of Hannover Medical School (No. 2021–2013) and by the Federal Commissioner for Data Protection and Freedom of Information in Germany. All participants provided written informed consent before entering the study. Consent was obtained from a parent or guardian on behalf of any participants under the age of 16.
: The authors declare that they have no competing interests.
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