PROJECT SUMMARY ABSTRACT — Vulnerable Aging Research Core (VARC) The Vulnerable Aging Research Core (VARC) supports OAIC investigators conducting primary data collection studies that include vulnerable older adults. Older adults are vastly underrepresented in research. This underrepresentation is even more pronounced for older adults with medical vulnerability (e.g., cognitive impairment and complex multi-morbidity) and/or social vulnerability (e.g., isolation, poverty, limited health literacy, homelessness). These medical and social vulnerabilities often coexist and interact to produce profound effects on disease incidence, progression, outcomes, and response to health interventions. Yet, older adults with these vulnerabilities are often difficult to recruit and retain, adversely affecting their representation in research and impairing our knowledge of how best to optimize their care. The UCSF Pepper Center has an international reputation for expertise in the recruitment, retention, and protection of medically and socially vulnerable older adults in research including in community-engaged research, prospective studies, and randomized trials. Since the VARC's inception last cycle, the number of OAIC investigators engaged in primary data collection of medically and socially vulnerable older adults has continued to grow exponentially, as have the services we provide to investigators. We propose the following aims: (1) Provide expert consultation for the design of primary data collection studies that focus on older adults with medical and/or social vulnerabilities, including human subject considerations; (2) Support OAIC-affiliated investigators on methods for recruiting, consenting, enrolling, and retaining vulnerable older adults, including convening and maintaining community advisory boards; (3) Support OAIC investigators on methods to develop and test interventions that are responsive to the needs and priorities of vulnerable older adults; (4) Advise on the incorporation of predictor and outcome measures of medical and social vulnerability (e.g., cognitive impairment, frailty, health literacy, poverty, social isolation) in collaboration with the Data and Analysis Core; and (5) Support Development Projects that advance the development of new methodologies in our Core's theme area. We propose a novel Development Project to develop innovative methods for merging qualitative and mixed methods data across studies involving older adults with disability and their care partners and clinicians. The VARC will also support stellar external investigators whose research involves recruiting and retaining vulnerable older adults. Proposed external projects include NIA-funded studies exploring barriers to long-term social support services for older adults with Alzheimer's Disease and Related Dementias and the effects of a novel decision support tool to help older adults discuss diabetes medication deprescribing with clinicians.