0887 Divergent Slow wave sleep and Alzheimer's disease Plasma Biomarkers’ Associations in Black and White Cognitive Normal Older-Adults

Abstract Introduction We determined whether slow wave sleep is associated with plasma levels of Aβ40, Aβ42, Aβ42/Aβ40, Tau, tau/Aβ42 and NfL and whether this relationship differed between Blacks/African-Americans and non-Hispanic Whites. Methods This was a cross-sectional analysis of baseline data from 171 community-dwelling cognitively normal older-adults, participating in ongoing NYU studies on memory, sleep and aging. Non-rapid eye movement sleep (NREM) slow wave sleep (SWS) duration was calculated from 2 nights of in-lab NPSGs. Plasma Aβ40, Aβ42, Tau and NfL were determined using single molecule array (SIMOA). Associations of NREM SWS duration and plasma AD biomarker levels were assessed using adjusted generalized linear models and Pearson correlation analysis after data normalization. Analyses were adjusted for age, sex, BMI, race, and education. Results Of the 171 subjects (128 non-Hispanic Whites and 43 Blacks/African-Americans), 112 (65.5%) were females, and mean (SD) age was 68.6 (6.6) years, BMI was 27.6 (6.1) kg/m**2, and education was 16.9 (2.1). There were no racial differences in age, sex, BMI, NREM SWS and AHI4%. Compared to non-Hispanic Whites, Blacks/African-Americans had significantly lower years of education (14.2 vs. 17.2, p <.01), plasma Aβ40 (248.3 vs. 262.5 pg/ml) and NfL levels (11.4 vs. 15.2 pg/ml) p<.05 for both. There were no significant racial differences in levels of plasma Aβ42, Aβ42/Aβ40, Tau, Tau/Aβ40 and Tau/Aβ42 (p>.05 for all). NREM SWS duration was not associated with plasma Aβ42, Aβ40 or tau in the overall sample (p>.05 for all). However, in non-Hispanic Whites, NREM SWS negatively correlated with plasma Aβ42 (r=-0.28, p<=0.05), plasma Aβ40 (r=-0.087, p=0.72), though not significant, and plasma Tau (r=-0.153, p=0.27), though not significant. In Black/African-Americans, NREM SWS positively correlated with plasma Aβ42 (r=0.48, p=0.05), plasma Aβ40 levels (r=0.32, p=0.04), and plasma Tau levels (r=0.52, p=0.04). NREM SWS was not associated with plasma tau/Aβ42, plasma tau/Aβ40 or plasma NfL in the overall sample and across racial subgroups. Conclusion Race-specific divergent associations between NREM SWS and plasma Aβ42, Aβ40 & Tau may suggest differences in SDOH factors and mechanisms that could influence sleep and AD-risk in older-adults. Support (if any) AASMBTS#231-BS-20, NIAK23AG068534A, AARG-D- 21-848397, BFFA2022033S