Funding for this research was provided by:
Horizon 2020 research and innovation programme (643708)
Text and Data Mining valid from 2019-11-04
Received: 24 April 2019
Accepted: 18 October 2019
First Online: 4 November 2019
Ethics approval and consent to participate
: Participants received an information letter in which they were briefly informed about the purpose of the study. By signing a written informed consent, they gave their consent to participation in the study. All applicable institutional regulations pertaining to the ethical use of human volunteers were followed during this research. Ethical approval was provided by the Ethical Committees of all participating European countries (i.e. Ethical committee of Ghent University Hospital (Belgium), Committee for the Ethics of the Scientific Studies (KENI) at the Medical University of Varna and the Municipality of Sofia (Bulgaria), Ethics Committee of Harokopio University of Athens, the Greek Ministry of Education, Research and Religious Affairs and the Municipalities of Kallithea, Peristeri, Piraeus and Keratsini-Drapetsona (Greece), CEICA (Comité Etico de Investigacion Clinica de Aragon (Spain), Ethics Committee of THL (Finland) and the Bioethics Committee of University of Debrecen (Hungary).
: Not applicable.
: The authors declare that they have no competing interests.