Author contributions
C.Y.P, K.H, J.H.S and K.S.K were involved in the conception, design, and
conduct of the study and the analysis and interpretation of the results.
J.H.S and K.S.K wrote the first draft of the manuscript, and all authors
edited, reviewed, and approved the final version of the manuscript.
C.Y.P is the guarantor of this work and, as such, had full access to all
the data in the study and takes responsibility for the integrity of the
data and the accuracy of the data analysis.