A Longitudinal Analysis of the Cognitive Function and Related Factors in Older Adults Using a Multilevel Growth Model

Abstract

Objectives: The purpose of this study is to examine changes in the cognitive function of the elderly over time and to identify factors affecting the cognitive decline by dividing them into multidimensional factors such as socio-demographic factors, physical and mental health factors, hearing factors, and social contact factors.Methods: This study used the Korean Longitudinal Study of Aging (KLoSA). A multilevel growth model analysis was conducted on 992 elderly people aged 60 or older who had been measured repeatedly seven times from 2006 to 2018.Results: First, the results showed that the cognitive function of the elderly decreased linearly over the years. Second, the initial status of cognitive function decreased as the age increased and as education level and economic condition decreased. The change rate of the cognitive function increased as education level increased. Third, at each time point, depression level had a negative effect on cognitive function, and subjective hearing condition had a negative effect on cognitive function. These influences decreased over time.Conclusion: The lower the education level, the higher the depression level; and the worse the subjective hearing condition, the more likely the elderly are to experience cognitive decline. Because the impact on cognitive function is large in the early stages of depression and hearing loss, it is necessary to detect them early and to make appropriate intervention to prevent cognitive decline.