Plasma beta-amyloid 40 levels are positively associated with mortality risks in the elderly

{Background: We evaluated if plasma beta-amyloid (A beta) levels were associated with mortality risks in a subsample of the French Three-City (3C) prospective cohort study. Methods: Analyses were based on 1254 participants randomly selected from the initial 3C cohort stratified by center, sex, and age in the context of a nested case-cohort study to investigate biological variables. Associations between plasma A beta and mortality were assessed with the Cox regression model with delayed entry including various potential confounding factors and testing possible mediators. Results: A relationship between high plasma A beta(1-40) concentrations and risk of mortality (hazards ratio, 1.15; 95% confidence interval, 1.01-1.31