APOE and Cognitive impairment: For instance, it lacks the completeness of Aβ-PET, cerebrospinal fluid tau, or Aβ examinations, given that only parts of the included population underwent Aβ-PET; (3) finally, this study focused on APOE ε4 alleles; thus, no evidence was provided for other related biomarkers and imaging approaches; and (4) the small sample size of OCI group in current study restricts us to further confirm the relationship between APOE ε4 and SCD-Q9 after control the amount of cognitive impairment, and a larger cohort with MCI and mild AD dementia patients was needed to verify our conclusion.