PROJECT SUMMARY/ABSTRACT: Project 4 (Lead: Patel; Early Stage Investigator) Spouse lifestyle choices and psychosocial characteristics may powerfully influence the other spouse’s cardiovascular disease (CVD) risk milieu. We have compelling preliminary baseline data from the Center for cArdiometabolic Risk Reduction in South Asia Cohort (CARRS) that the odds of overweight, hypertension, diabetes, and depression are twice as high in adults who have a spouse with those same conditions. These cross-sectional associations of spousal CVD risks raise questions regarding whether development of CVD in one spouse can assist in more precisely predicting future risk of CVD in the partner. Identifying the mechanisms of specific spousal influences on CVD development may inform contextually-tailored, family-level interventions to target modifiable CVD risk factors. In Project 4 of Precision-CARRS, we will investigate spouse dyads already enrolled in the CARRS cohort to better understand the independent influence of spouses on the natural history of subclinical and clinical vascular and myocardial disease. CARRS is a large and diverse community-based cohort of 21,864 South Asian adults aged ≥ 20 years residing in Delhi and Chennai, India. By design, one randomly selected man and woman per sampled household were recruited at baseline, yielding 5,931 spouse dyads (n= 11,862 adults; 54% of the cohort), followed for up to 10 years (median: 5 years). Through Precision-CARRS, we will utilize repeated measures of traditional atherosclerotic CVD (ASCVD) risk factors collected since baseline, novel phenotyping of subclinical and clinical CVD disease (CVD phenotyping Core). In addition, Project 4 will collect new, real-time data on sleep characteristics, physical activity levels, diet, and psychosocial factors over a 7-day observation period using low-burden mHealth technologies (wearable wristband tracker and smartphone application; n=1,500 spousal dyads). Analyses will account for individual-level risk factors and also quantify the role of shared environmental risk factors such as built environment and air pollution (Project 2) in the development of CVD risk. Our aims are to: Aim 1. Evaluate spousal influences on ASCVD risk factors. Aim 2. Determine the relationship between spousal CVD measures and subclinical and clinical vascular disease and myocardial disease. Aim 3. Evaluate interpersonal mechanisms of spousal influences by examining day-to-day associations in health behaviors and psychosocial measures that are risk factors for CVD in a subsample of 1,500 dyads. Project 4, led by an Early Stage Investigator, adds to Precision-CARRS by identifying how the development of CVD—from early risk to clinically manifest disease—is independently influenced by one’s spouse. Expanding CVD risk assessment to include spouse’s CVD related behaviors and outcomes will highlight pathways for risk reduction and may inform more precise and early identification of CVD.