1. Department of Epidemiology, Brown University, Providence, Rhode Island, USA
2. Department of Environmental Health, and
3. Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, USA
4. Cardiovascular Epidemiology Research Unit, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
5. Geriatric Neuropsychology Laboratory, Department of Veterans Affairs Medical Center, Boston, Massachusetts, USA
6. Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts, USA, and
7. Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA