Cognitive Dysfunction in Urban-Community Dwelling Prefrail Older Subjects

Hiroyuki Umegaki, T. Makino, H. Shimada, T. Hayashi, X. Wu Cheng, M. Kuzuya

A number of studies have reported that frailty is cross-sectionally associated with cognitive decline and is also a risk for future cognitive decline or dementia; however, there have been only a few studies that focus on the association between prefrailty and cognitive dysfunction. In the current study, we investigated the association between prefrailty and cognition. A cross-sectional study of the data obtained at registration in a randomized control trial. Toyota, Japan. Community-dwelling older subjects (male 54.6%) who had cognitive complaints. A battery of neuropsychological and physical assessments were performed. Prefrailty was defined as exhibiting one or two of the five Fried criteria (weight loss, exhaustion, weakness, slow gait speed and low physical activity). We performed a multiple regression analysis to investigate the associations of cognitive performance with prefrailty, adjusting for the factors that were significantly different between the robust and prefrailty groups. To assess the cognitive attributes that were significantly associated with prefrailty, logistic analysis was performed to see if one specific criterion of the five frailty criteria was associated with cognitive performance. The study subjects included 183 prefrail and 264 robust individuals. The prefrail subjects with cognitive complaints were older, less educated, more depressive, and more likely to have diabetes mellitus than the robust subjects. The prefrail subjects had lower performance in a wide-range of cognitive domains, and after adjustments for age, education, depressive mood, and diabetes mellitus, prefrailty was associated with a decline in delayed memory and processing speed. Among the components of the Fried criteria, slow gait speed and loss of activity were significantly associated with slow processing speed as assessed by the digit symbol substitution test. The current results demonstrated that prefrailty was associated with worse memory and processing speed performance, but not with other cognitive domains.