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Illiteracy Effect on Cognitive Decline in a Rural Elderly Population: A 3-year Follow up Study  

Kwon, Oh Dae (Department of Neurology, School of Medicine, Catholic University of Daegu)
Kwak, Jae Hyuk (Department of Neurology, School of Medicine, Catholic University of Daegu)
Publication Information
Dementia and Neurocognitive Disorders / v.10, no.2, 2011 , pp. 52-57 More about this Journal
Abstract
Background: This study aimed to know the effects of illiteracy versus literacy on the longitudinal change of cognitive function in later life. Methods: The baseline and follow-up surveys were conducted in 2007 and 2010, respectively. The participants analyzed in the present study were 191 subjects who were 65 to 86 years old at baseline, living in a rural Korean community. Education level were categorized into three groups, illiterate (n=64) who cannot read and write even their own name, 1 to 5 yr of education (n=54), above 6 yr of education (n=73). Cognitive function was assessed using Korean version of Mini-Mental State Examination (K-MMSE), Clinical Dementia Rating (CDR) including CDR sum of boxes (CDR-SB), Korean version of Instrumental Activities of Daily Living (K-IADL) and Geriatric depression scale-short form (GDS-S). Demographic characteristics, past history of illness, family history, and life style were evaluated as covariates. Results: All the baseline neuropsychological tests were lower in illiterate group. Proportion of women was highest in illiterate group (92.2%), followed by low education (64.8%) and high education (28.8%). CDR-SB scores (F=3.788, p=0.024) and K-IADL (F=3.432, p=0.034), when adjusted for age and gender, showed that cognitive decline of illiterate group was severe than the literate two groups. On the other hand, K-MMSE scores (F=0.039, p=0.962), CDR-Global scores (F=1.950, p=0.145), and GDS-S scores (F=0.869, p=0.421) did not show significant differences among the three groups. Regression analysis showed that educational level (p=0.078) and family history of stroke (p=0.065) has marginal significance on the change in cognitive function. Conclusions: Illiterate subjects showed faster cognitive decline than literate subjects as well as lower baseline neuropsychological test scores, which support cognitive reserve theory.
Keywords
Cognition; Illiteracy; Cognitive reserve; Education;
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