Alzheimer's Disease (AD) prevention and control currently face severe challenges, with limited treatment options and effectiveness available. Once the disease progresses to the AD stage, it is essentially irreversible. Before the onset of AD, there is a prolonged asymptomatic period and a stage of mild cognitive impairment (MCI), which represents a critical window for early screening, diagnosis, and intervention. Therefore, early screening, diagnosis, and intervention during the MCI stage are crucial for slowing or halting the rising trend of AD and alleviating its disease burden.

This study plans to enroll elderly individuals from communities around Peking University Third Hospital to establish a prospective cohort. Participants will undergo cognitive assessments and blood biomarker testing, followed by a three-year follow-up and management program. The study aims to obtain epidemiological data on MCI and AD in community populations, investigate the relationships between known risk factors, genetic factors, and blood biomarkers with disease progression, explore additional biomarkers, and develop predictive models. These efforts will contribute to promoting early diagnosis, early intervention, and improved prognosis.

Inclusion Criteria:

1. Aged 55 years or older;
2. No diagnosis of Alzheimer's disease (AD);
3. Participants are able to complete cognitive tests, provide biological samples, undergo neuroimaging examinations, and cooperate throughout the entire study process;
4. Signed informed consent.

Exclusion Criteria:

1. Participants with severe mental illness, tumor-related cachexia, severe hepatic or renal insufficiency, or other major physical conditions that may hinder cooperation with the examinations;
2. Participants who are unable to complete the required assessments due to visual or hearing impairments;
3. Contraindications for MRI or other study-related examinations.

This study will enroll elderly individuals meeting the inclusion/exclusion criteria from communities surrounding Peking University Third Hospital.