Project Summary Rising life expectancy is contributing to rapid increases in the size of the older population and is expected to lead to a sharp rise in Alzheimer’s disease and Alzheimer’s disease related dementias from about 47 million people worldwide today, to potentially more than 140 million in 2050. Less education is one of the most influential modifiable risk factors of dementia, but its cause pathways are less understood in the U.S. context due to the challenge in data collection and potential confounding with other factors. Lifestyle factors as well as environmental factors might further reduce or increase an individual’s risk of developing dementia, particularly interacting with education and other resources one may receive at a younger age. We propose to advance our understanding of protective and risk factors for late-life cognitive decline and Alzheimer’s disease and Alzheimer’s disease-related dementias (hereafter referred to as dementia) in China, a large population with more variable levels of education attainment under rapid and broadly impactful social and economic shifts. We propose a novel life-course model of risk factors, building on the recently proposed model by the Lancet commission, which links dementia risk to early and mid-life factors, within the context of historical, organizational, and physical environments, including obesity, diabetes hearing loss, visual impairment, smoking, drinking, depression, physical inactivity, and social isolation. Specifically, this project aims to further study early and mid-life personal, family, and social factors that may contribute to late-life cognition and dementia risk using new, retrospective lifehistory interview data in China. These findings will deepen our understanding of potential causes and risk factors of the disease and thus inform potential strategies to improve the prevention and detection of Alzheimer’s Disease in the United States.