1 UT Health Science Center San Antonio, Department of Epidemiology and Biostatistics, Mail Code 7933, 7703 Floyd Curl Drive, San Antonio, Texas 78229-3900, U.S.A.
2 Vanderbilt University Medical Center, Center for Biomedical Ethics and Society, 2525 West End Avenue, Suite 400, Nashville, Tennessee 37203, U.S.A.
3 UT Health Science Center San Antonio, Department of Epidemiology and Biostatistics, San Antonio, Texas 78229-3900, U.S.A.
4 UT Health Science Center San Antonio, Department of Medicine, San Antonio, Texas 78229, U.S.A.