Submitted for Publication: September 28, 2011; final revision received December 22, 2011; accepted January 18, 2012.
Author Contributions: Dr Woodward had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. All statistical analyses were conducted by Drs Kuo and Woodward.
Financial Disclosure: None reported.
Funding/Support: This work was supported under a VA/Department of Defense (DoD) assistance agreement to Drs Kaloupek and Woodward from the US Army Medical Research and Material Command (DoD) administered through the Institute for Medical Research (VA).
Additional Contributions: The Research Services of the VA Palo Alto Health Care System and VA Boston Health Care System provided invaluable support for this study. Important institutional and technical support was also provided by the following individuals: at VA Palo Alto Health Care System: Wendy Stegman, BA, Lorraine Leskin, PhD, Ned Arsenault, BA, John E. Drace, MD, Patricia Spezia, BA, Carla Ambriz, BA, and Gary E. Gold, MD; at Stanford University: Thomas J. Brosnan, PhD, Anil Patwardhan, PhD, Eric Schmitt, PhD, Allan Reiss, MD, and Stephan Eliez, MD, PhD; at VA Boston Health Care System: Rebecca Prestel, BA, Catherine Kutter, PhD, Kelly Teresi, BA, Frederick Kanter, MD, Steven Blank, BA, Susan Proctor, DSc, Chris Streeter, MD, Matthew O. Kimble, PhD, and Erica Stone; at McLean Hospital: Perry Renshaw, MD, PhD, Blaise Frederick, PhD, Rosemond Villafuerte, Ann Smith, BA, and Eileen Connolly, BA; and at Defense Manpower Database Command, Michael A. Dove, MBA. Ruth O’Hara, PhD, provided valuable consultation in the preparation of this manuscript. Stegman, Leskin, Prestel, Kutter, Teresi, and Renshaw received financial compensation for their contributions.