Cognitive function in the prefrailty and frailty syndrome.

Objectives: To explore the relationship between cognitive function and frailty.

Design: A cross-sectional study using data from Wave 1 of The Irish Longitudinal Study on Ageing, a population representative study of adults aged 50 and older in the Republic of Ireland.

Setting: Community-dwelling adults completed a home- or health center-based nurse-led assessment.

Participants: Individuals aged 50 and older without a history of stroke, Parkinson's disease, or severe cognitive impairment (Mini-Mental State Examination (MMSE) score <18) and not taking antidepressants (N = 4,649).

Measurements: A cognitive battery including MMSE, Montreal Cognitive Assessment, Color Trails Test, Cambridge Mental Disorders of the Elderly Examination memory and executive function subtests, 10-word recall, Sustained Attention to Response Task, and choice reaction time was used to generate composite scores of cognitive domains. Frailty was assessed according to weakness, slowness, exhaustion, low physical activity, and weight loss.

Results: After full adjustment, cognitive function across all domains except self-rated memory and processing speed was significantly worse in prefrail and frail participants (P < .05) than in those who were robust. Weakness and walking speed were most consistently linked to poorer cognition, whereas low activity and weight loss were not independently associated with any cognitive domain. Exhaustion was associated with global cognition (B = -0.18 ± 0.06), with some evidence of links to objectively measured and self-rated memory.

Conclusion: Cognitive function is worse across multiple cognitive domains in prefrail and frail individuals aged 50 and older than in those who are robust, although the absolute differences are small after adjusting for confounding factors.