Volunteering, Polygenic Risk, and Cardiovascular Biomarkers in Multiple Ancestry Groups - ABSTRACT There is increasing knowledge that volunteering is salutary for volunteers’ cardiovascular health. At the same time, more than 50% of adults over the age of 50 in the U.S. report at least one cardiovascular risk such as hypertension, high cholesterol, obesity, and chronic inflammation. Despite decades of research indicating that frequent volunteers show better cardiovascular disease (CVD) biomarkers, little is known whether frequent and sustained volunteering affects change in CVD biomarkers in multiple population subgroups, net of selection into volunteering. Further, genetic susceptibility to CVD biomarkers has never been studied in the context of volunteering. Our preliminary data show that frequent volunteering (200+ hours a year) predicts favorable CVD biomarkers, including chronic inflammation, systolic, and diastolic blood pressure in longitudinal analysis even when selection effects are considered through inverse probability treatment weighting. This highlights a critical need for understanding the pathways by which genetic, social, and behavioral factors affect cardiovascular health in older adults (NIA strategic research priorities B-2). In response to PA-20-185 and NOT-AG-21-020 Maximizing the Scientific Value of Secondary Analyses of Existing Datasets, the present study uses the Health and Retirement Study and seeks to understand whether changes in volunteering are linked to CVD biomarkers over a decade after adjusting for selection into volunteering and pre-baseline characteristics, and whether these links are stronger for multiple genetic, demographic, and socioeconomic subgroups. Using seven CVD biomarkers and polygenic risk scores, this study addresses three specific aims: Aim 1) examine the longitudinal effects of sustained volunteering on CVD biomarkers (N=18,847), Aim 2) test the associations between genetic predictors of CVD biomarkers, volunteering and CVD biomarkers in multiple ancestry groups (European N=8,400, African N=1,605), and Aim 3) assess the effect heterogeneity of volunteering on CVD biomarkers in multiple genetic, demographic, and socioeconomic subgroups. This project seeks to quantify the effects of volunteering on multiple CVD biomarkers while addressing important questions about selection effects and genetic susceptibility for a better causal inference. Addressing this gap in research is critical for developing new public health policies and biobehavioral and social interventions for heart-healthy older adults.