Published Online: August 26, 2013. doi:10.1001/jamainternmed.2013.9382.
Study concept and design: Sheehy, Graf, Jacobs.
Acquisition of data: Sheehy.
Analysis and interpretation of the data: Sheehy, Graf, Gangireddy, Formisano, Jacobs.
Drafting of the manuscript: Sheehy.
Critical revision of the manuscript for important intellectual content: Graf, Gangireddy, Formisano, Jacobs.
Obtaining funding: Sheehy.
Administrative, technical, or material support: Graf, Gangireddy, Formisano, Jacobs.
Conflict of Interest Disclosures: Dr Graf reports receiving royalties from Smith & Nephew for patents he has assigned to them involving orthopedic implants used in arthroscopic surgery. No other disclosures are reported.
Funding/Support: This study was supported by the University of Wisconsin Department of Medicine (Dr Sheehy). Dr Jacobs was supported by the National Institutes on Aging, grant R01 AG033172-01.
Role of the Sponsors: The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication
Additional Contributions: We thank Daniel S. Dexter, BA, for assistance with the data set, Andrew T. LaRocque, BBA, for assistance with data presentation, and Cynthia Heidke, BA, for assistance with data presentation and editing. They received no additional compensation for their work on this study.