Longitudinal Evidence of Social Influences on Cognitive Decline in South Korea: Focusing on the Joint Effects of Age, Gender, and Education *

Abstract

(ProQuest: ... denotes formulae omitted.)IntroductionSouth Korea experiences one of rapid population aging in the world. The proportion aging over 60 year old is about 18.5% in 2015 yet is projected to be 41.5% in 2050. According to UN, Korean population composition is one of the youngest among the 34 OECD countries in 2015 but is projected to be one of the oldest in 2050(Would Population Prospects: The 2015 Revision). Aging population produces increasing number of age-related diseases such as Alzheimer Disease (AD), or diseases associated with cognitive decline (CD). Prevalence of AD, for example, is 9.18% in 2012 and is expected to be 15.06% in 2050. Even higher ratio of increases of AD prevalence relative to composition of elderly population over about 35 years may call for further attention to this issue. Furthermore, the care costs in the domains of finance and emotion, with respect to AD or CD are burdensome both for individuals and society, deserving careful and well-planned policies (Kurz et al. 2003; Toseland et al. 2002). Lastly, the fact that there is no medical cure available for individuals with severely impaired cognition may contribute to widespread notion of regarding AD as mysterious and unpredictable diseases and the ways in which to deal with uncertainty are indeed in high social demand, locally and globally.Aforementioned daunting nature of CD does have received wide range of research interests or attentions investigating (a) genetic influences or biological processes of pathological CD and/or, (b) potential risk factors for such diseases processes. Although these lines of past research are important in many respects, we argue that dynamic social processes underlying such disease process have not been fully examined yet. First, previous research taking risk-factor approach has identified various risk-factors for cognitive decline, such as low education level, female, older age, but it has not been clear how these risk factors come to affect cognitive decline. For example, low level of education has been identified as significant risk factor but it remains to be learned whether such low educational risk even accelerates with advancing age. Second, relatedly, previous research documented inconsistent patterns with respect to female disadvantage in cognitive decline. Is it possible to attribute lack of consistent findings of female disadvantage to lack of considering relevant contexts that might have been responsible for the gender difference? Lastly, besides overall research trend of paying insufficient attention to socio-environmental processes, much of previous work examining social processes underlying cognitive decline relied on cross- sectional or short-term follow up data, rendering caution in the extent of statistical inferences or generalization of findings.We address these shortcomings of previous research on cognitive decline by investigating whether or how multiple risk factors such as low level of education, older age, female come to have effects on cognitive decline. In particular, our investigation is centered on testing the extent of socio-environmental influences on cognitive decline by testing female disadvantage hypothesis. In essence, the process is to validate the existence of such disadvantage and, if so, is furthered assessed by more rigorous contingency of basic association such as age and education. To do this, we employ recent five waves of Korean Longitudinal Study of Ageing and follow respondents who have successfully completed all follow-up surveys up to 2014, and use random-intercept approach to appropriately examine long term change in the area of research interest. Lastly, Cognitive health score is measured via MMSE (i.e., Mini Mental State Examination).Background1) Fundamental Causes of Health Inequality and Cognitive DeclineFundamental cause theory posits that one's location in hierarchical social position is a fundamental cause of population health disparities because one's social position affects a range of health outcomes through a host of risk factors. …