Midlife Plasma AB and Latelife Risk of MCI/Dementia Supplemental Material

Objective. To evaluate the association between midlife plasma amyloid-beta (Aβ1-42, Aβ1-40, Aβ42:Aβ40) and risk of MCI and dementia.

Plasma Aβ42 and Aβ40 were retrospectively measured using a fluorimetric bead-based immunoassay in a subsample of the Atherosclerosis Risk in Communities study (n=2284) at the third (1993-95, mean age=59.2±5.2, 57% female, 22% Black) and fifth in-person visits (2011-13, mean age=77.0±5.3). We investigated the relationship of plasma Aβ42, Aβ40, and Aβ42:Aβ40 ratio measured in midlife, late-life, and the change from midlife to late-life, to risk of MCI, dementia, and combined MCI/dementia outcomes in late-life (from 2011-19). We used multinomial logistic regressions estimating relative risk ratios (RRR) of these cognitive outcomes vs cognitively normal adjusted for age, sex, education, site-race, APOE, hypertension, diabetes, and body mass index. Each doubling of midlife Aβ42:Aβ40 was associated with 37% lower risk of MCI/dementia (RRR=0.63, 95% CI: 0.46, ...