1. Intramural Research Program; Laboratory of Epidemiology and Population Sciences; National Institute on Aging; National Institutes of Health; Bethesda Maryland
2. Department of Ophthalmology; The Johns Hopkins University School of Medicine; Baltimore Maryland
3. Longitudinal Studies Section; National Institute on Aging; Baltimore Maryland
4. Department of Preventive Medicine; University of Tennessee; Memphis Tennessee
5. Department of Epidemiology and Biostatistics; UCSF School of Medicine; San Francisco California
6. Department of Epidemiology; Graduate School of Public Health; University of Pittsburgh; Pittsburgh Pennsylvania