Received: 27 April 2017
Accepted: 1 February 2018
First Online: 13 February 2018
Ethics approval and consent to participate
: The study was performed according to the principles of the Declaration of Helsinki. It was reviewed and approved by the Office of The Committee for Research Ethics (Social Sciences), Mahidol University, prior to its commencement, in April 2015 (Certificate of Approval No.: 2015/115.1803) and all participating institutions. Written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interest.
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