Division of Geriatric Medicine, Department of Medicine, Dalhousie University, Nova Scotia Health Authority, Halifax, Canada. Centre for Health Care of the Elderly, Veterans' Memorial Building, 4121-5955 Veterans' Memorial Lane, Halifax, Nova Scotia, B3H 2E9, Canada. Division of Geriatric Medicine, Department of Medicine, Dalhousie University, Nova Scotia Health Authority, Halifax, Canada. Kenneth.Rockwood@nshealth.ca. Centre for Health Care of the Elderly, Veterans' Memorial Building, 4121-5955 Veterans' Memorial Lane, Halifax, Nova Scotia, B3H 2E9, Canada. Kenneth.Rockwood@nshealth.ca. Department of Medicine, Divisions of Geriatric Medicine & Neurology, Dalhousie University, Nova Scotia Health Authority, Halifax, Canada. Kenneth.Rockwood@nshealth.ca.