Risk factors and cognitive domain markers of progression in subjective cognitive decline

BackgroundSubjective cognitive decline (SCD) is increasingly recognized in some cases as an early clinical stage in the Alzheimer's disease continuum, yet the factors that predict which individuals will progress to objective impairment remain poorly understood.ObjectiveWe evaluated risk factor differences and cognitive domain markers associated with progression in participants with subjective cognitive decline (SCD) at baseline from the NYU Alzheimer's Disease Research Center.MethodsWe included SCD non-decliners (n = 27), who remained stable, and decliners (n = 24), who progressed to mild cognitive impairment or worse, between the second to sixth yearly follow-up visits. Adjusted mixed-effects models examined group differences and associations between demographic, APOE status, psychometric test performance and comorbidities with longitudinal-decline.ResultsOverall, mean (SD) age was 67.4 (9.2) and total follow-up time was 5.1 (1.8) years. Lower education (14.9 (3.2) versus 17.3 (2.1)), Hispanic ethnicity (50.0% versus 11.0%), and hypercholesterolemia (adjusted odds ratio: 6.67) were risk factors for progression in SCD, p ≤ 0.05, whereas APOE status was not. Notably, SCD decliners were at increased risk for both amnestic and non-amnestic cognitive-decline with psychometric changes in memory, executive, and language domains (p < 0.001 for all).ConclusionsThese findings inform further work on SCD outcomes and related biomarkers, as well as preventive studies that target modifiable risk factors for SCD progression.