PROJECT SUMMARY By 2030, 8.5 million Americans will be diagnosed with Alzheimer’s disease and related dementias (ADRD); yet because socioeconomically disadvantaged populations are underrepresented in ADRD research, the extent of ADRD disparities by socioeconomic factors are poorly understood. Food insecurity, a condition of limited food availability due to insufficient resources, is an understudied dimension of socioeconomic disadvantage and a persistent health concern in the United States. Food insecurity has increased 128% among older adults since 2001, and has been associated with lower cognitive function in limited cross-sectional studies. The lack of rigorous research investigating the effect of food insecurity on cognitive impairment and ADRD risk is a widely acknowledged gap in the health disparities and ADRD literature, and represents a major missed opportunity to better understand how a key social determinant of health can influence cognitive aging in later life. The overall objective for this application is to understand the longitudinal and dynamic effects of food insecurity on cognitive impairment and ADRD risk. The central hypothesis is that food insecurity increases the risk of accelerated cognitive impairment and ADRD through poor diet quality, cardiometabolic health conditions, psychological distress, and poor mental health, all of which has been demonstrated by prior research. Food insecurity is both preventable and reversible; therefore, the rationale for this project is that establishing food insecurity as a risk factor for cognitive impairment and ADRD risk will inform public health strategies to address and prevent the dual burden of food insecurity and ADRD among older adults. To achieve the proposed aims, this project will leverage data from two well-established cohort studies: 1) the Panel Study of Income Dynamics (PSID), the longest running nationally representative household panel survey, and 2) the Health and Retirement Study (HRS), the leading nationally representative study on aging. Our specific aims are to: 1) evaluate the dynamic effects of food insecurity in adulthood on ADRD risk; 2) identify the longitudinal effects of food insecurity on trajectories of cognitive impairment; and 3) examine heterogeneity by sociodemographic characteristics and diet quality on the effects of food insecurity on cognitive impairment and ADRD risk. By leveraging data from two nationally representative studies, this project will be the first to provide a complementary and comprehensive understanding of the long-term effects of food insecurity on cognitive impairment and ADRD risk. These results will have significant clinical, public health, and policy implications by identifying a modifiable risk factor to promote healthy cognitive aging and improve quality of life, particularly among socioeconomically disadvantaged populations.