Objective: The Nanshan Elderly Cohort Study (NECS) aims to investigate the nutritional, as well as other environmental and genetic factors of chronic diseases, such as cardio-metabolic diseases. Study design: NECS is a community-based prospective cohort study. Participants: About 10000-20000 apparently healthy residents, living in Nanshan， Shenzhen (South China) for \>5 years, aged ≥ 65 years, will be recruited between 2018 and 2019. Visits and Data Collection: Participants will be followed up approximately every 3 years by invited to the Community Healthcare Service Centre. At each survey, face-to-face interviews, anthropometric measurements, ultrasonography examination, electrocardiogram test and specimen collection will be conducted. Key variables: 1. Face-to-face interviews: Structured questionnaires will be used to collect the participants' socio-demographic characteristics, lifestyles, habitual dietary intake, physical activity, history of chronic diseases, use of supplements and medications, family history, psychological health and cognitive function. 2. Physical examinations: Anthropometric measurements, blood pressure tests, handgrip strength, and usual gait speed. 3. Ultrasonography examinations: Ultrasonography examination will be performed to determine carotid artery intima-media thickness and plaque, fatty liver. 4. Electrocardiogram test: Electrocardiogram test is to obtain information about the structure and function of the heart. 5. Specimen collections: Overnight fasting blood sample, early morning first-void urine sample and faeces samples will be collected and stored at -80°C till tests. 6. Laboratory tests: 1. Blood tests: Metabolic syndrome-related indices; nutritional indices; inflammatory markers; sexual hormones; genetic markers. 2. Urinary tests: Flavonoids and flavones, minerals, creatinine and renal function related markers. 3. Fecal test: Gut microbiota and related metabolites. 7. Morbidity and mortality: Relevant data will be also retrieved via local multiple Health information systems. 8. Others: Many other laboratory tests or instrument tests will be developed depended on needs and resources in future.