Influence of Frailty on Cognitive Decline: A Population-Based Cohort Study in Rural Ecuador.

Objective: To assess the influence of frailty on cognitive decline.

Design: Population-based prospective cohort study.

Settings/participants: Community-dwelling older adults living in a rural Ecuadorian village, fulfilling the following criteria: age ≥60 years at baseline Montreal Cognitive Assessment (MoCA) and frailty assessment, a baseline brain magnetic resonance imaging, and a follow-up MoCA performed at least 12 months after the baseline.

Measures: Frailty was evaluated by the Edmonton Frailty Scale (EFS) and cognitive performance by MoCA. The relationship between baseline EFS and MoCA decline was assessed by longitudinal linear and fractional polynomial models, adjusted for relevant confounders. The score of the cognitive component of the EFS was subtracted, and an alternative fractional polynomial model was fitted to settle the impact of such cognitive question on the model.

Results: A total of 252 individuals, contributing 923.7 person-years of follow-up (mean: 3.7 ± 0.7 years) were included. The mean EFS score was 4.7 ± 2.5 points. The mean baseline MoCA score was 19.5 ± 4.5 points, and that of the follow-up MoCA was 18.1 ± 4.9 points (P = .001). Overall, 154 (61%) individuals had lower MoCA scores in the follow-up. The best fitted longitudinal linear model showed association between baseline EFS score and MoCA decline (P = .027). There was a continuous increase in MoCA decline in persons with an EFS ≥7 points (nonlinear relationship). Fractional polynomials explained the effect of the EFS on MoCA decline. For the complete EFS score, the β coefficient was 2.43 (95% confidence interval 1.22-3.63). For the effect of the EFS (without its cognitive component) on MoCA decline, the relationship was still significant (β 4.86; 95% confidence interval 2.6-7.13).

Conclusions/implications: Over a 3.7-year period, 61% of older adults living in Atahualpa experienced cognitive decline. Such decline was significantly associated with frailty status at baseline. Region-specific risk factors influencing this relationship should be further studied to reduce its burden in rural settings.