APOE and Parkinson disease: Carriers of APOE-ε4 or any GBA mutation were significantly younger at the time of PD diagnosis compared with non-carriers in both unadjusted analysis (Table 1) and after adjustment for sex and study cohort (APOE-ε4, β, −2.31; 95% CI, −3.58 to −1.04; P < 0.001; GBA carriers, β, −2.89; 95% CI, −4.82 to −0.96; P = 0.003).