1. From the Departments of Epidemiology (P.M., D.K.A.) and Medicine (P.M., S.O.), University of Alabama at Birmingham, Birmingham, AL; Department of Medicine (D.S.), Columbia University, New York, NY; Department of Medicine (M.T.), University of Alberta, Edmonton, Alberta, Canada; Department of Research & Evaluation (K.R.), Kaiser Permanente Southern California, Pasadena, CA.