Effects of cognitive ageing trajectories on multiple adverse outcomes among Chinese community-dwelling elderly population

Abstract

Background: Whether cognitive ageing trajectory is related to common functional deficits independent of initial cognitive function remains inconclusive. We aimed to explore the adverse health effect and potential predictive factors of distinct cognitive trajectories among Chinese older adults.

Methods: Three thousand five hundred eighty-one community-dwelling older adults who completed three consecutive cognitive function examinations with the Mini-Mental State Examination (MMSE) over 5 years and were without cognitive impairment at enrollment were included. A group-based trajectory model was used to estimate cognitive ageing trajectories. Multivariable-adjusted odds ratio (OR) and 95% confidence intervals (CI) were computed with logistic regression models to identify potential baseline determinants and health effect of cognitive trajectories on various adverse outcomes.

Results: Two distinct cognitive ageing trajectories were identified with about 5.3% of the study participants ascribed to the rapidly decreasing group. Subjects with rapidly decreasing cognition showed significantly higher odds (OR, 95%CI) of experiencing frailty (4.04, 2.77-5.86), falls (2.01, 1.05-3.70), balance impairment (4.20, 2.75-6.38), high fall risk (5.66, 2.67-11.77) based on the Tinetti total score, disability in activities of daily living (1.76, 1.19-2.56), disability in instrumental activities of daily living (1.52, 1.05-2.19), and motor cognitive risk syndrome (2.24, 1.23-3.98) compared with their steadily decreasing counterparts. Individuals with older age, low education level, no marriage, high score of rapid eye movement behavior disorders, poor physical and cognitive function at baseline were more predisposed to an accelerated cognitive decline.

Conclusions: Faster cognitive decline was independently associated with higher risk of multiple adverse events. Our findings put more emphasis on a routine and constant surveillance of cognitive function among community-dwelling older adults.

Keywords: Ageing; Chinese; Cognitive decline; Functional deficits; Trajectory.

Fig. 1

Trajectory modeling identified two cognitive trajectory groups in the BLSA-II cohort of Chinese community-dwelling elderly population. Their patterns by age, the number, and percentage were shown for each group. Grey shades indicate 95% confidence intervals

Fig. 2

Forest plots of the relative risk of frailty and its component events between the steadily decreasing group and rapidly decreasing group of cognitive function. Model 1: unadjusted model; Model 2: adjusted for all the sociodemographic confounders, health behaviors, and comorbidities; Model 3: adjusted above covariates plus baseline MMSE, GDS, and ADL score; Model 4: adjusted for covariates in model 3 and baseline levels of targeted outcomes. Abbreviations: CI, confidence interval; OR, odds ratio

Fig. 3

Forest plots of the relative risk of other functional deficits between the steadily decreasing group and rapidly decreasing group of cognitive function. Model 1: unadjusted model; Model 2: adjusted for all the sociodemographic confounders, health behaviors, and comorbidities; Model 3: adjusted for above covariates plus baseline MMSE, GDS, and ADL score as appropriate; Model 4: adjusted for covariates in model 3 and baseline levels of targeted outcomes. Abbreviations: ADL, activities of daily living; CI, confidence interval; IADL, instrumental activities of daily living; MCR, motor cognitive risk syndrome; OR, odds ratio; RBD, rapid eye movement disorders