Kim, Seong-Jang
Pak, Kyoungjune
Kim, Keunyoung
Article History
First Online: 2 January 2019
Compliance with ethical standards
:
: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of this study.
: Institutional review board approval was not required because we only performed data analysis based on the published studies.
: Written informed consent was not required for this study because it is a meta-analysis based on the studies that have been published.