Project Summary/ Abstract Diabetes is a mounting public health concern, with millions of new cases each year. Poor control of diabetes is associated with serious health complications, including heart disease, blindness, and amputation. Control of diabetes can be achieved through adherence to diet, exercise, and treatment guidelines, but compliance with prescribed regimens can be complicated and difficult. The Look AHEAD study randomized an intensive lifestyle intervention focused on weight reduction among over 5,000 patients with type 2 diabetes in 2001. Participants in the intervention lost weight and improved their diabetes control over the 11 years of the intervention relative to the control group. Weight reductions and improvements in diabetes outcomes may lead to broader benefits for patients in terms of functional status, ability to work, and fewer health complications. We propose research linking Look AHEAD participants with data from Medicare and the Social Security Administration to determine the effect of the intervention on long-term health care utilization (e.g. hospital admissions), employment, earnings, retirement, and severe disability (as measured by enrollment in disability insurance). In addition, we will simulate the long-term fiscal impacts of a broader, national expansion of the intensive lifestyle intervention. Finally, we will compare health and disability measures collected by the Look AHEAD study to overlapping measures in Medicare and the Social Security Administration data, to evaluate the use of administrative data as a source of health information in clinical trials. The results of this study will provide important evidence on the broader benefits of successful lifestyle interventions for diabetes. In addition, the results will indicate the impact of improved diabetes control on functional status and economic outcomes.