Author Contributions: Drs Teno and Gozalo had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Teno, Gozalo, Dosa, Intrator, Mor.
Acquisition of data: Teno, Hsu.
Analysis and interpretation of data: Teno, Mitchell, Gozalo, Dosa, Intrator, Mor.
Drafting of the manuscript: Teno, Mitchell, Dosa.
Critical revision of the manuscript for important intellectual content: Teno, Mitchell, Gozalo, Dosa, Hsu, Intrator, Mor.
Statistical analysis: Teno, Mitchell, Gozalo, Intrator, Mor.
Obtained funding: Teno.
Administrative, technical, or material support: Gozalo, Hsu, Mor.
Study supervision: Teno.
Financial Disclosures: None reported.
Funding/Support: This research was funded by grants RC1AG036418 and P01AG027296 from the National Institute on Aging. Dr Mitchell is supported by grant K24AG033640 from the National Institute on Aging.
Role of the Sponsor: The National Institute on Aging had no role in the design and conduct of the study, in the collection, management, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript.
Additional Contributions: We thank Chris Brostrup-Jensen, BA (senior programmer, Brown University, Providence, Rhode Island), for his work in building the database and Cindy Williams, BS (research assistant, Brown University), for assistance in manuscript preparation. Their contribution was part of their employment at Brown University; therefore, they did not receive any external compensation.