1. From the Center for American Indian Health Research, University of Oklahoma Health Sciences Center, Oklahoma City, OK (JX and ETL); Medstar Research Institute, Hyattsville, MD (SE-A, BVH, and CM); the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (CL and RRF); the Indian Health Service, Aberdeen Area Office, Aberdeen, South Dakota (EMZ); and the Department