Funding for this research was provided by:
Faculty of Medicine Research Fund, Chiang Mai University, Chiang Mai, Thailand.
Received: 7 November 2018
Accepted: 15 January 2019
First Online: 26 January 2019
Ethics approval and consent to participate
: Informed consent was obtained from all participants. The study was approved by the Research Ethics Committee, Faculty of Medicine, Chiang Mai University (No: 313/2016).
: Not applicable.
: The authors declare that they have no competing interests in this section.
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