Published Online: April 22, 2013. doi:10.1001/jamainternmed.2013.567
Author Contributions: Dr S. E. Lee 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. Study concept and design: Jeong and S. E. Lee. Acquisition of data: Jeong, S. Lee, Byun, and D. H. Lee. Analysis and interpretation of data: Jeong and S. Lee. Drafting of the manuscript: Jeong. Critical revision of the manuscript for important intellectual content: S. Lee, Byun, D. H. Lee, and S. E. Lee. Statistical analysis: Jeong and S. Lee. Administrative, technical, and material support: Byun. Study supervision: D. H. Lee and S. E. Lee.
Conflict of Interest Disclosures: None reported.
Additional Contributions: Soyeon Ahn, PhD (Medical Research Collaboration Center, Seoul National University Bundang Hospital), provided statistics consultation and support.