Remnant cholesterol and cognitive function: Evidence from the China health and retirement longitudinal study

Background: Evidence on associations of remnant cholesterol (RC) and its variability with cognitive function is still lacking. Objective: To explore the association of RC and its variability with cognitive function. Methods: Participants were recruited from a population-based cohort, the China Health and Retirement Longitudinal Study (CHARLS). Cognitive function was assessed by a standardized questionnaire from CHARLS, with domains of episodic memory and mental intactness. A linear mixed effects model was used to analyze the association of RC with cognitive function, along with its variability (calculated as standard deviation [SD], coefficient of variation [CV], variability independent of the mean [VIM]), with results expressed as β (95%CI). Potential subgroup differences in the association of RC and its variability with cognitive function were also explored. Results: 4234 participants were eventually included, with mean (SD) age of 57.4 (8.0) years. Each 10 mg/dL increase in RC was associated with 0.053 (95%CI: 0.096, 0.009) points, 0.021 (95%CI: 0.042, 0.000) points, 0.032 (95%CI: 0.064, 0.001) points decrease in global cognitive function, episodic memory, and mental intactness scores, respectively. Compared with the first tertile (T1) group of RC variability (calculated as SD, VIM), T3 showed a lower level in global cognition and episodic memory after multivariate adjustment. The potential modification effects of educational level on RC and its variability in relation to cognitive function were also identified. Conclusions: Among Chinese middle-aged and older adults, higher RC level were associated with worse cognitive function. Greater RC variability was also associated with worse cognitive performance, especially in memory function.