Author Contributions: Dr Anthony had full access to all of 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: Fowler, Gallagher, Skinner.
Acquisition of data: Fowler, Gallagher, Anthony, Skinner.
Analysis and interpretation of data: Fowler, Anthony, Larsen, Skinner.
Drafting of the manuscript: Fowler, Gallagher, Anthony.
Critical revision of the manuscript for important intellectual content: Gallagher, Anthony, Larsen, Skinner.
Statistical analysis: Fowler, Anthony, Larsen, Skinner.
Obtained funding: Gallagher, Skinner.
Financial Disclosures: None reported.
Funding/Support: This study was supported by grant P01 AG19783 from the National Institute on Aging to Dartmouth Medical School.
Role of the Sponsor: The National Institute on Aging had no role in the design and conduct of the study; the collection, analysis, or interpretation of the data; or the preparation, review, or approval of the manuscript.