Abstract
The prolongation of life expectancy for the elderly in the developed world has created several issues requiring urgent appropriate responses for certain clinical phenotypes, such as geriatric syndrome. Among these phenotypes, frailty and dementia are thought to play important roles, and their mutual interaction, diagnosis, and preventive measures must be clarified and developed based on highly refined evidence-based epidemiologic studies. Geriatric syndrome is characterized by various signs including delirium, falls, incontinence, pressure ulcers, and general functional declines, and the resulting frailty promotes impairments in IADL and ADL associated with a dependent state of daily living. Although studies on the relation between frailty and dementia have been sparse, several recent epidemiologic studies have disclosed that the prevalence of dementia among individuals with frailty and the prevalence of frailty among individuals with dementia exhibit similar tendencies. One of these studies was a prospective 5-year follow-up cohort study performed on 407 non-frail subjects (78 ± 4 years), in which the following 4 predictors for frailty were identified: decreased timed walk (<3 seconds/5 meters), increased pulse pressure (>60mmHg), decreased cognitive function (subjective), and increased hearing deficit (subjective), with 93% negative and 70% positive predictive values. Since all these predictors are also risk factors for cognitive impairment, frailty and dementia might be mutually related in some way. Also, a generalized concept of geriatric syndrome and new conceptual models addressing the pathophysiology of geriatric syndromes in a manner reflecting the complex interaction between frailty and dementia were discussed. Although further studies are needed to confirm these results, some sort of evaluation and preventive measures for both frailty and dementia should be proposed to the elderly from the standpoint of health evaluations and health promotion. Especially, cognitive hearing science should be extensively studied to promote hearing rehabilitation procedures, and the effects of antihypertensive medication should also be explored with special reference to the specific domains of cognitive function that can be affected.
