1. Institute for Research in Extramural Medicine, Vrije University Medical Center, 1081 BT Amsterdam, The Netherlands;
2. Laboratory of Epidemiology, Demography and Biometry, National Institute on Aging, Bethesda, Maryland 20892;
3. Sticht Center on Aging, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157;
4. Department of Preventive Medicine, University of Tennessee, Memphis, Tennessee 38105; Departments of
5. Epidemiology and
6. Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261; and
7. Department of Epidemiology and Biostatistics, University of California, San Francisco, California 94105