Predictors of Changes in Cognitive Function in Older Korean Adults: The 2006–2018 Korean Longitudinal Study of Aging

Abstract

Cognitive decline with normal aging varies widely among individuals. This study aimed to investigate predictors of longitudinal changes in cognitive function in community-dwelling Korean adults aged 65 years and older. Data from 727 older adults who participated in the Korean Longitudinal Study of Aging (KLoSA) survey from 2006 (baseline) until 2018 (seventh wave) were used. Cognitive performance was assessed with the Korean Mini-Mental State Examination. The participants were retrospectively classified into normal cognition, mild cognitive impairment, and moderate/severe cognitive impairment. Education, income, religion, living area, alcohol intake, smoking, physical activity, handgrip strength, functional dependency, depression, comorbidity, medications, fall experience, and unintentional weight loss were included as covariates. A linear mixed regression analysis showed that a steeper decline in cognitive function over time was significantly associated with parameters of poor socio-economic status, health conditions, and unhealthy behaviors. Individuals with mild cognitive impairment or moderate/severe cognitive impairment were likely to have steeper cognitive declines compared with individuals with normal cognition. The current findings of the study showed that age-related cognitive decline was multifactorial in older Korean adults.

Community support and promoting cognitive function for the elderly

“…Education can also improve their cognitive abilities ( Inouye et al, 1993 ; Lee et al, 2003 ). Furthermore, a good lifestyle can slow cognitive decline ( Kang et al, 2021 ), such as physical activity ( Lü et al, 2016 ) and fitness ( Daimiel et al, 2020 ) as well as good nutrition ( Smith and Blumenthal, 2016 ). On the contrary, smoking increases the risk of cognitive impairment in the elderly ( Souza-Talarico et al, 2021 ).…”

The effect of risk factors on cognition in adult cochlear implant candidates with severe to profound hearing loss

“…It is usually considered that above all, cognitive performance is mainly related to age (i.e., the older the patient is, the worse cognition scores) because of the associated physiological neuropathological alterations. The effect of age on cognition has been widely described ( Völter et al, 2020 ; Kang et al, 2021 ). Here, it comes into play the “common cause hypothesis,” advocating a common factor as the responsible for the continuous decline in physiological structures with aging.…”

“…Some authors have advised that prevention of cognitive impairment could reduce cognitive decline in individuals with normal aging ( Kang et al, 2021 ). However, there is a great variance among individuals.…”

“…Based on the assumption that healthy behaviors can protect against dementia ( Livingston et al, 2020 ; Kang et al, 2021 ), we asked participants about their frequency of physical activity, smoking and drinking habits, as well as diagnosed health conditions of obesity, diabetes, hypertension, and previous head injury. Drawing causal relationships between these factors is not straightforward, as several risk factors influence others.…”

“…Recently, a prospective study was conducted with 727 Korean participants (≥65 years old) with no cognitive disorder at recruitment concluded. This study identified several risk factors for age-related cognitive decline, including low socio-economic status (poor education, low income, living in a rural area), unhealthy behaviors (unintentional weight loss, reduced hand grip strength), and health conditions (depression; Kang et al, 2021 ). Likewise, demographic features such as sex and marital status have been identified as risk factors for age-related dementia ( Legdeur et al, 2018 ; Zhang et al, 2019 ).…”