Factors predicting episodic memory changes in older adults with subjective cognitive decline: A longitudinal observational study

Abstract

Episodic memory is affected early in the neuropathological process of Alzheimer's dementia. This study was performed to identify longitudinal associations between baseline vascular/neuropsychiatric risk factors and episodic memory changes over 4.1 ± 2.4 years in 1,401 older adults with subjective cognitive decline (age 74.0 ± 8.2 years). Data were from the National Alzheimer's Coordinating Center-Uniform Data Set and linear mixed effects regression models were used. Reference was those without risk factors. Participants with hypercholesterolemia and with former cigarette smoking had higher episodic memory scores, but current smokers had fewer points than reference at their first and follow-up visits. Despite no difference at baseline, episodic memory scores decreased in those with depressive symptoms relative to reference over time. In older adults with subjective cognitive decline, interventions managing current smoking and depressive symptoms could preserve episodic memory, which may result in delaying the onset of Alzheimer's dementia. Further research is required for the role of cholesterol and smoking.

Keywords: Alzheimer's dementia; Cigarette smoking; Depressive symptoms; Episodic memory; Hypercholesterolemia; Subjective cognitive decline.

Fig. 1.

Predicted episodic memory scores by hypercholesterolemia, smoking history, and depressive symptoms. Results were from the full model adjusting for selected predictors and all covariates. Reference is a condition without hypercholesterolemia, smoking history, and depressive symptoms.