1. Section of Internal Medicine and Geriatrics, Department of Clinical and Experimental Medicine, University of Ferrara, Ferrara, Italy
2. Department of Geriatric Rehabilitation, University Hospital of Parma, Parma, Italy
3. Tuscany Regional Health Agency, Florence, Italy
4. Geriatric Unit, Azienda Sanitaria di Firenze, Florence, Italy
5. Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland
6. Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, Baltimore, Maryland