APOE and diabetes mellitus: Table 2 showed that there was a negative correlation between eGFR and plasma NfL in both the unadjusted model 1 (B = − 0.190, 95% CI − 0.224 to − 0.156, P < 0.001) and the multivariate model 2 adjusting for age, sex, education, BMI, and APOE genotype (B = − 0.093, 95% CI − 0.126 to − 0.060, P < 0.001) and model 3 further adjusting for stroke, hypertension, and diabetes (B = − 0.010, 95% CI − 0.133 to − 0.068, P < 0.001).