Text and Data Mining valid from 2018-05-30
Received: 16 March 2018
Accepted: 21 May 2018
First Online: 30 May 2018
Ethics approval and consent to participate
: The study protocol was reviewed and approved by the Ethics Committee of the Pirogov Russian National Research Medical University (Protocol No.2017/23); the study was conducted in accordance with the Declaration of Helsinki. All participants (children’s parents) provided written informed consent.
: The authors declare that they have no competing interests.
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