Funding for this research was provided by:
Korea Centers for Disease Control & Prevention (2004-E71004-00; 2005-E71011-00; 2005-E71009-00; 2006-E71001-00; 2006-E71004-00; 2006-E71010-00; 2006- E71003-00; 2007-E71004-00; 2007-E71006-00; 2008-E71006- 00; 2008-E71008-00; 2009-E71009-00; 2010-E71006-00; 2011- E71006-00; 2012-E71001-00; 2013-E71009-00)
Received: 29 June 2017
Accepted: 10 May 2018
First Online: 13 June 2018
Ethics approval and consent to participate
: The HEXA study protocol was approved by the Institutional Review Board (IRB) of the Seoul National University Hospital, Seoul, Korea (IRB number 0608–018- 179) and the Korea National Institute of Health (IRB number 2014–08-02-3C-A). All study participants gave written informed consent prior to entering the study.
: The authors declare that they have no competing interests.
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