Meanwhile, multivariate Cox regression analysis revealed that higher baseline CSF GFAP levels in PD–NC patients could still predict the risk of dementia during 8 years of follow-up, even after controlling for age, gender, education level, APOE ε4 carrying status and disease duration (HR = 3.070, 95% CI 1.119–8.418, p = 0.029; Additional file 1: Table S7 Model 1). This evidence concerns the gene APOE and Parkinson disease.