Multivariate logistic regression examined factors associated with cognitive impairments, including APOE ε4, Geriatric Depression Scale (GDS) score, Non‐motor Symptom Questionnaire (NMS) score, Movement Disorder Society–Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS‐UPDRS) Part II score, and physical activity level. This evidence concerns the gene APOE and major depressive disorder.