Institution: | 1. Department of Epidemiology and Biostatistics, Mail Code 7933, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78229‐3900, U.S.A.;2. Department of Biostatistics, Boston University, 801 Massachusetts Avenue, Boston, Massachusetts 02118, U.S.A.;3. Department of Biostatistics, University of North Carolina at Chapel Hill, North Carolina 27599, U.S.A. |