Accepted for Publication: November 25, 2013.
Published Online: March 31, 2014. doi:10.1001/jamainternmed.2014.348.
Study concept and design: Cheng, X. Li, He, Chen.
Acquisition of data: Cheng, W. Zhang, X. Zhang, Han, Q. Li, Chen.
Analysis and interpretation of data: Cheng, Han, Chen.
Drafting of the manuscript: All authors.
Critical revision of the manuscript for important intellectual content: Cheng, Chen.
Statistical analysis: Cheng, W. Zhang, X. Zhang, X. Li, Q. Li, Chen.
Obtained funding: Chen.
Administrative, technical, or material support: He, Chen.
Study supervision: Chen.
Conflict of Interest Disclosures: None reported.
Funding/Support: This work was supported by grant 2012CB517603 from the National Basic Research Program of China and by grant N20120291 from the Zhejiang Provincial Education Department.
Role of the Sponsor: The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.