1. Department of Epidemiology, Tulane University School of Public Health, New Orleans, LA 70112; USA
2. Division of Pulmonary, Emory University School of Medicine, Atlanta, GA 30322; USA
3. Department of Biostatistics and Bioinformatics, Emory University School of Public Health, Atlanta, GA 30322; USA
4. Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
5. Center for American Indian Health Research, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104; USA
6. Medstar Research Institute and Georgetown and Howard Universities Centers for Translational Sciences, Washington, DC 20007