Higher preoperative blood NfL and GFAP levels independently predicted POD after adjusting for age, sex, dementia, frailty, and Interleukin-6 (Odds Ratio, OR: 3.21, 95% Confidence Interval, CI: 1.26-8.21, and OR: 3.66, 95% CI: 1.38-9.68, respectively). Here, IL6 is linked to dementia.