Cognitive Function in Individuals With Physical Frailty but Without Dementia or Cognitive Complaints: Results From the I-Lan Longitudinal Aging Study

Abstract

ObjectiveTo investigate if understated cognitive impairment existed in individuals with physical frail or earlier prefrail state but without cognitive complaints and the susceptible cognitive domains to the physical frailty. DesignA cross-sectional population-based community study. SettingI-Lan County of Taiwan. ParticipantsA total of 1839 community residents aged 50 years or older in the I-Lan Longitudinal Aging Study. InterventionNone. MeasurementsFrail status assessments by the Cardiovascular Health Study (CHS) criteria and a series of neuropsychiatric assessments, including the Mini-Mental State Examination (MMSE), the delay free recall in the Chinese Version Verbal Learning Test (CVVLT), the Boston Naming Test (BNT), the category (animal) Verbal Fluency Test (VFT), the Taylor Complex Figure Test (CFT), the digital backward (DB), and the Clock Drawing Test. ResultsAfter excluding those with significant global cognitive impairment, subjective cognitive complaints, or functional impairment, 1686 persons aged 50 to 89 years (mean 63.4 ± 8.9) were enrolled. The prevalence of prefrail and frail individuals was 40.2% and 4.9%, respectively. The prefrail and frail persons had significantly poorer performance in the MMSE and all neuropsychological tests. Slowness and weakness were the most significant frailty components associated with cognitive impairment. The prefrail and frail individuals showed a more dose-dependent risk for 1 or more cognitive domain impairments than the robust individuals (odds ratio [OR] 1.28 in prefrail individuals versus OR 1.79 in frail individuals). The susceptible cognitive domains in the prefrail state were mainly focused on the nonmemory domains. However, the frail individuals were more likely to have risks for impairment in both memory and nonmemory domains. ConclusionsEven without subjective cognitive complaints, higher risk of cognitive impairment is presented in the prefrail and frail individuals. The incremental impact of frailty on cognition and the susceptibility of nonmemory domain may provide a new view in evaluating the pathogenesis of the relationship between frailty and cognitive impairment.