Published Online: June 3, 2013. doi:10.1001/jamainternmed.2013.6895
Study concept and design: Baillargeon, Urban, Ottenbacher, and Goodwin.
Acquisition of data: Baillargeon.
Analysis and interpretation of data: All authors.
Drafting of the manuscript: Baillargeon, Urban, and Goodwin.
Critical revision of the manuscript for important intellectual content: Baillargeon, Urban, Ottenbacher, Pierson, and Goodwin.
Statistical analysis: Baillargeon and Pierson.
Obtained funding: Goodwin.
Administrative, technical, and material support: Urban, Ottenbacher, and Goodwin.
Study supervision: Baillargeon, Urban, and Goodwin.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by grants 5P30AG02482, 1UL1RR029876-01, K05-CA134923, UL1TR000071, and R24HD065702 from the National Institutes of Health.
Role of the Sponsors: The funding organizations had no role in the design or conduct of the study; in the collection, analysis, or interpretation of data; or in the preparation, review, or approval of the manuscript.
Correction: This article was corrected June 3, 2013, for errors in percentages in the Results and Discussion sections.