Perceived Stress, Blood Biomarkers, and Cognitive Functioning in Older Adults

Introduction: There is a substantial gap in knowledge regarding how perceived stress may influence the relationship between serum-measured biomarkers for Alzheimer's disease and cognitive decline. Methods: This study consists of 1118 older adult participants from the Chicago Health and Aging Project (CHAP) (60% Black participants and 63% female participants). Linear mixed effects regression models were conducted to examine the role of perceived stress in the association between three blood biomarkers: total tau (t-tau), glial fibrillary acid protein (GFAP), and neurofilament light chain (NfL) on global cognitive decline. Stratified analysis by stress level was also conducted to evaluate the associations between each blood biomarker and baseline cognitive function and decline. All models adjusted for age, race, sex, education, time, and their interactions with time. Results: The interaction of stress, NfL concentration, and time was statistically significant on global cognition (beta = -0.064 [SE = 0.028], p = .023) and on episodic memory (beta = -0.097 [SE = 0.036], p = .007). Conclusions: Greater stress level worsens the association between high NfL concentration and cognitive decline. Stress management interventions may be helpful to reduce the rate of cognitive decline in individuals with high concentrations of NfL.