Shanghai At Risk for Alzheimer's Disease: a Cohort Study

Inclusion Criteria: 1. the AD diagnostic criteria of probands meet the 2011 National Institute on Aging - Alzheimer's Association framework, and participants are the first-degree relatives (including parents, children and siblings of the same father and mother) of the proband; 2. not patients with dementia; 3. ≥ 50 years, males and females; 4. subjects have lived in Shanghai for more than 1 year and have no plan to move out of Shanghai within 5 years; 5. subjects are able to complete investigation, physical examination, imaging examination and biological specimen collection. Exclusion criteria: Individuals will be excluded if they have: 1. other diseases which could cause cognitive decline, e.g. cerebrovascular diseases, Creutzfeldt-Jakob disease and Parkinsons disease; 2. history of psychological disorders (according to Diagnostic and Statistical Manual of Mental Disorders, 5th Edition); 3. uncorrectable visual or auditory impairment that hampers the completion of related examination. 4. pre-menopausal women will also be excluded.