The Boston Puerto Rican Health Study at Northeastern University is one of ten Centers for Population Health and Health Disparities (CPHHD) funded by the National Institutes of Health (NIH). This program responds to a strategic priority at the NIH to address disparities and inequities in the prevalence and outcomes of several diseases. The CPHHD program requires transdisciplinary research involving social, behavioral, biological, and genetic research to improve knowledge of the causes of health disparities and devise effective methods of preventing, diagnosing and treating disease and promoting health. A 10.2 million dollars award from the National Heart, Lung, and Blood Institute of the NIH funded the Northeastern University CPHHD. Puerto Rican adults living on the United States mainland have documented health disparities; however, little research has been conducted with this second largest Hispanic subgroup. The Center's long-term goal is to understand the complex interactions of diet and other behavioral and environmental factors, genetics, and psychosocial stress on the high and apparently increasing prevalence of cardiovascular disease (CVD) risk factors in Puerto Rican adults. The Boston Puerto Rican Health Study is composed of 5 interrelated research projects, centered on an established cohort of 1500 Puerto Ricans, aged 45-75 years at baseline. Projects 1-4 directly build upon data obtained in the first two interview cycles (baseline and 2-year), during the initial 5-year funding period (2003-2009), by adding additional measures in a third 5-year interview. These additional measures include heart disease risk (project 1); additional measures of the social environment and stress (project 2); the role of genetic factors in heart disease risk progression (project 3); and the role of air pollution on heart disease risk (project 4). The center is also conducting a multidimensional community-based intervention focusing on diet and exercise, with consideration of social integration, to reduce heart disease risk (project 5).