Funding for this research was provided by:
Korea Health Technology R&D Project through the Korea Health Industry Development Institute (HC15C1322)
Received: 24 August 2017
Accepted: 29 January 2018
First Online: 6 February 2018
Ethics approval and consent to participate
: The Korea National Health and Nutrition Examination Survey (KNHANES) was approved by the Ethics Committee of the Korea Centers for Disease Control & Prevention (2007-02CON-04-P, 2008-04EXP-01-C, 2009-01CON-03-2C, 2010-02CON-21-C, 2011-02CON-06-C, 2012-01EXP-01-2C, 2013-07CON-03-4C, and 2013-12EXP-03-5C). All study participants provided a written informed consent to agree the data to be used in national statistics and research. The KNHANES data is open to the public after anonymization.
: Not applicable as this manuscript does not include details, images, or videos relating to individual participants.
: The authors declare that they have no competing interests.
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