Author Contributions: Dr Schulman 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: Kansagra, Curtis, Schulman.
Acquisition of data: Curtis, Schulman.
Analysis and interpretation of data: Kansagra, Curtis.
Drafting of the manuscript: Kansagra.
Critical revision of the manuscript for important
intellectual content: Kansagra, Curtis, Schulman.
Statistical analysis: Kansagra, Curtis.
Administrative, technical, or material support: Schulman.
Study supervision: Schulman.
Previous Presentation: Presented in part at
the Alpha Omega Alpha Symposium at the Duke University School of Medicine;
May 11, 2004; Durham, NC.
Acknowledgment: We thank Kevin J. Anstrom,
PhD, for statistical advice and Damon M. Seils, MA, for editorial assistance
and manuscript preparation.