Division of Research, Kaiser Permanente of Northern California, Oakland;
Departments of Edidemiology, Biostatistics, and Medicine, University of California at San Francisco, San Francisco;
Clinical Epidemiology unit, General Medicine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston;
Clinical Epidemiology unit, General Medicine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston;
Division of Research, Kaiser Permanente of Northern California, Oakland;
Clinical Epidemiology unit, General Medicine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston;
Division of Research, Kaiser Permanente of Northern California, Oakland;
Division of Research, Kaiser Permanente of Northern California, Oakland;
Division of Research, Kaiser Permanente of Northern California, Oakland;
Clinical Epidemiology unit, General Medicine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston;