APOE and Parkinson disease: For instance, the HRs were 0.79 (95% CI, 0.64–0.97) and 0.86 (95% CI, 0.71–1.04) in ApoE ε4 noncarriers and carriers for the risk of dementia (p for interaction 0.7158); in participants with education of A level or above and other education level the HRs were 0.95 (95% CI, 0.73–1.24) and 0.78 (95% CI, 0.66–0.92) with an insignificant interaction (p 0.2470); and the HRs were 1.00 (95% CI, 0.75–1.33) and 1.17 (95% CI, 0.87–1.57) in participants aged <65 years and ≥65 years respectively for PD risk (p for interaction 0.5302).