1. Department of Epidemiology, University of Kentucky, Lexington, KY, USA
2. Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
3. Department of Pathology, University of Kentucky, Lexington, KY, USA
4. Department of Neurology, University of Kentucky, Lexington, KY, USA
5. Baptist Neurology Center, Lexington, KY, USA
6. Department of Biostatistics, University of Kentucky, Lexington, KY, USA
7. Department of Statistics, University of Kentucky, Lexington, KY, USA