NEFL and dementia: However, PD patients with high serum NfL levels were found to have a higher likelihood of transitioning from normal cognition to MCI or dementia (HR 1.107, 95% CI 1.010–1.213, p = 0.030; Supplementary Table 1) in logistic regression analysis, after adjusting for various factors including age, gender, history of hypertension, history of diabetes, history of atrial fibrillation, history of prior myocardial infarct, history of prior stroke, BMI, education level, disease duration, baseline UPDRS III scores, baseline H&Y, baseline MoCA scores, and LEDD.