Cognitive decline and mortality among community-dwelling Chinese older people

Abstract

BackgroundWhether cognitive decline is related to a higher risk of death independent of the initial cognitive function is inconclusive. Evidence of the association between cognitive decline and mortality among Chinese older people is limited. We aimed to examine whether cognitive decline, assessed by the rate of decrease in the Mini-Mental State Examination (MMSE) score, was associated with mortality independent of initial cognitive function (baseline MMSE score) among Chinese older people.MethodsWe established two successive and non-overlapping cohorts of older adults nested within the Chinese Longitudinal Healthy Longevity Survey (CLHLS), an ongoing, open, community-based cohort survey conducted every 2–3 years. Cognitive function was measured using the Chinese version of the MMSE. A total of 11,732 older adults who completed two consecutive cognitive function examinations were included and followed for 3 years. A Cox proportional hazards model was used to examine the association of cognitive decline with mortality after adjusting for sociodemographic characteristics, health behaviours, comorbidities and initial cognitive function.ResultsThe mean age was 82.5 years old, and 44.9% (5264/11732) of participants were men. After adjusting for baseline MMSE scores and other covariates, the rate of change in MMSE scores over 3 years was monotonically and positively associated with subsequent 3-year mortality. Compared to those with stable cognitive function, participants with rapid cognitive decline (decline faster than average, a reduction of MMSE scores > 1.62 points/year) had a 75% higher risk of death (hazard ratio = 1.75, 95% confidence interval 1.57–1.95). The association between cognitive decline and mortality was stronger among relatively younger Chinese older people (aged 65–79 years versus 80 years and over) and those with normal cognitive function at baseline (MMSE scores ≥ 24 versus < 24 points), respectively, but did not differ by cohort and sex.ConclusionFaster cognitive decline was associated with higher mortality independent of initial cognitive function, especially among those aged 65–79 years and those with normal cognitive function at baseline. The association was consistent across two successive cohorts. Our findings indicate the practical significance of monitoring cognitive change in older adults.

Cognitive Function and Mortality: Results from Kaunas HAPIEE Study 2006–2017

“…A previous study established that a 5-year mortality risk increased among women with mild cognitive impairment and dementia compared to women with normal cognition, which accounts for traditional prognostic indicators [7]. Some studies did not find a significant difference between men and women in this association [13]. Another previous study ascertained that the risk was higher in the male group [15].…”

“…It was proposed that cognitive function decline is related to mortality, even independently of the initial level of cognitive abilities [13]. The mechanisms under this link are still unknown, but might include a decreased ability to follow the medical regime and self-care.…”

Predicting Non-elective hospital readmission or Death using a Composite Assessment of Cognitive and Physical Frailty in Elderly inpatients with Cardiovascular Disease

“…Cognitive impairment is a risk factor for adverse events in patients with CVD [10]. The most widely used tool for evaluating cognitive impairment is the MMSE [25]. However, the MMSE is language-based and considered to be influenced by the level of education.…”

Predicting Non-elective hospital readmission or Death using a Composite Assessment of Cognitive and Physical Frailty in Elderly inpatients with Cardiovascular Disease

“…Cognitive impairment is a risk factor for adverse events in patients with CVD [10]. The most widely used tool for evaluating cognitive impairment is the MMSE [27]. However, the MMSE is language-based and considered to be influenced by the level of education.…”