1. From the Division of Clinical Epidemiology, Department of Medicine, University of Texas Health Science Center, San Antonio (K.J.H., M.P.S.); Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, Tex (R.D., H.H.H.G., J.T.W., L.A., J.B.); and Department of Radiology, Tufts New England Medical Center, Boston, Mass (D.H.O.).