1. From the Center for American Indian Health Research, University of Oklahoma Health Sciences Center, Oklahoma City, OK (JX, MB, and ETL); the Medstar Research Institute, Hyattsville, MD (SEA, BVH, and CM); the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (CML and RRF); and the Indian Health Service, Aberdeen Area Office, Aberdeen, SD (EMZ)