Funding for this research was provided by:
Estonian Ministry of Education and Science Institutional Grant (IUT 20-58)
Text and Data Mining valid from 2018-04-13
Received: 17 September 2017
Accepted: 4 April 2018
First Online: 13 April 2018
Ethics approval and consent to participate
: Written informed consents from parent and child were obtained from all participants. The study was approved by the Medical Ethics Committee of the University of Tartu, Tartu, Estonia, approval no 2-42 T 7. The study has performed in accordance with the Declaration of Helsinki.
: The manuscripts does not include details, images, or videos relating to an individual person.
: The authors declare that they have no competing interests.
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