Text and Data Mining valid from 2018-06-28
Received: 3 April 2018
Accepted: 22 June 2018
First Online: 28 June 2018
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of the Institute of Public Health of the University of Porto (ISPUP), which waived the need for written informed consent from the participants considering the anonymous nature of the collected data.
: Not applicable.
: The authors declare that they have no competing interests.
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