Is low cognitive performance a risk for dementia in elderly people with few years of education?

Objectives: Low cognitive performance (LCP), commonly observed in the individuals with low educational attainment, has been suggested in previous studies to reflect brain or cognitive reserve. This study aimed to investigate how LCP affects cognitive aging and the onset of dementia by examining the natural trajectory of cognitive changes in the older Korean adults.Method: Longitudinal data from 139 of the initial 243 individuals enrolled in the Cognitive Aging Study were analyzed using mixed-effect and logistic regression models. We examined cognitive trends of LCP individuals and the predictive power of LCP for dementia conversion.Results: First, the cognitive function of the LCP group increased slightly over the first three years but began to decline sharply thereafter compared to normal cognitive performance (NCP) group. Second, the dementia conversion rate was about five times higher in LCP group than NCP group at the final follow-up.Discussion: LCP is associated with an increased long-term risk of developing dementia, although it is not necessarily a sign of cognitive impairment in individuals with low education. These findings suggest that the cognitive performance of a normal individual may reflect currently available cognitive resources and could serve as a potential index of cognitive reserve.