A-4 Cerebrospinal Fluid and Plasma Neurofilament Light in Relation to Longitudinal Objective and Subjective Cognitive Decline in Older Adults

Abstract

Abstract Objective Cerebrospinal fluid (CSF) and plasma neurofilament light (NFL) concentrations were assessed in relation to longitudinal objective and subjective cognitive outcomes in older adults ranging from normal cognition to mild cognitive impairment. Interactive effects were assessed for apolipoprotein E ϵ4 (APOE4) carriership, a strong genetic risk factor for Alzheimer’s disease and molecular moderator of vascular disease. Method Vanderbilt Memory & Aging Project participants (CSF n = 149, 72 ± 6 years; plasma n = 333, 73 ± 7 years) underwent fasting blood draw and lumbar puncture at baseline for NFL quantification. Serial neuropsychological assessments and subjective cognitive decline (SCD) questionnaires were completed at 18-month increments. Linear mixed effects regression models adjusted for age, sex, race/ethnicity, education, APOE4 carriership (for main effect models), and depressed mood. NFL x APOE4 interaction terms were used as predictors in follow-up models. Results CSF NFL predicted steeper declines in an executive functioning composite score (β = −0.0001, p = 0.001) and WAIS-IV Coding (β = −0.001, p = 0.001). An APOE4 interaction was present for executive functioning (β = −0.0002, p = 0.005) such that CSF NFL associations with longitudinal decline were stronger among APOE4+ participants. Plasma NFL predicted worsening SCD (β = 0.27, p = 0.002) and objective cognitive decline across all domains (p-values <0.05), with multiple APOE4 interactions (p-values <0.05) suggesting stronger associations with objective cognitive decline among APOE4+ participants. Conclusions Both CSF and plasma NFL detect neuropathology associated with cognitive decline among non-demented older adults, especially among APOE4 carriers. Findings further support the value of SCD as reflecting neurodegenerative changes associated with accelerated cognitive aging.