1. Adams School of Dentistry, University of North Carolina at Chapel Hill, NC
2. Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC
3. Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY
4. Robert N Butler Columbia Aging Center, Mailman School of Public Health, Columbia University, New York, NY
5. Carolina Population Center, University of North Carolina at Chapel Hill, NC
6. Division of Infectious Diseases, School of Medicine, University of North Carolina at Chapel Hill, NC
7. Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC.