Patterns and risk factors of cognitive decline among community-dwelling Korean older adults: The Korean Longitudinal Study of Aging (2006–2016)

Abstract

Background Dementia prevalence is increasing worldwide, and thus, the global impact of cognitive impairment and dementia has become a priority public health issue. This study aimed to assess the patterns of and risk factors for cognitive decline over time in community-dwelling Korean adults aged ≥ 65 years. Methods Older adults with normal cognitive function at baseline in 2006 were evaluated, and changes in their cognitive function were followed over time. The data were obtained from the 2006–2016 Korean Longitudinal Study of Aging. Cognitive function in 2016 was classified based on the Korean-Mini-Mental State Examination score as normal, mild dementia, and moderate and severe dementia. The t-test, ANOVA, and linear mixed models were used to analyse the patterns and risk factors f cognitive decline over time. Results Of the 1,262 participants examined, 752 maintained normal cognitive function, 267 older adults showed a change from normal cognitive function to mild dementia, and 243 older adults showed a decline from normal cognitive function to moderate and severe dementia between 2006 and 2016. There were significant differences in cognitive function over time among the three groups, and these were influenced by age, gender, education level, religion, activities of daily living, instrumental activities of daily living, regular exercise, number of meetings with friends, and depression. The differences have gradually increased over 10 years. Conclusions This study identified the patterns of cognitive decline over time and important factors related to cognitive decline. Individualised interventions such as improving physical function through regular exercise, increasing social activity, and managing depression by early detection and treatment may contribute to maintain cognitive function.