GFAP and Parkinson disease: Low GFAP was also associated with a clinical diagnosis of PD/PDD (three [75%] PD/PDD; one [25%] DLB; zero AD) more than high GFAP (eight [24%] PD/PDD, eight [24%] DLB, and 18 [53%] AD) (Fisher's test: P = 0.039).