Aims: To investigate whether glucose and lipids are the risk factors for brain aging-related conditions, such as mild cognitive impairment. Subjects and

Methods: A community-based survey will be carried out in 10000 natural population aged \>=50 years selected from 10-12 communities stratified according to geographic regions (Ciyao, Huafeng, Dongzhuang, Heshan, Geshi, Jiangji, Gangcheng, Fushan, Dongshu, Sidian, Baxianqiao, and Xiangyin, etc) in Ningyang County, Taian City, Shandong Province. A comprehensive examination including questionnaire (including the MMSE and ADL evaluation for the participants), anthropometric measurements, biochemical analysis will be performed in each study participant. In particular, the investigators randomly selected 1000-2000 participants performing MRI of the brain to evaluate the brain aging related conditions. Phase 2: Cohort follow-up Aims : To examine glucose and lipids metabolism levels and their changes that modify the risk of brain aging-related conditions. Subjects and Methods: To recruit and follow all 10000 participants for at least 3-5 years. In particular, all 1000-2000 participants with the baseline MRI examination will perform the MRI examination again for the follow-up.