Genetic factors play an important role in diabetes mellitus, its risk factors and complications, but most of the specific genetic determinants remain unidentified. The molecular pathways by which diabetes-susceptibility genes influence risk for diabetes and related conditions are also largely unknown. This project will seek to identify, and quantify the effects of, the genetic determinants of type 2 diabetes, its risk factors and complications in a multiethnic sample. Diabetes and glycemic status will be assessed from clinical interviews, an oral glucose tolerance test and glycated hemoglobin. Insulin sensitivity and insulin secretion will be assessed from indices derived from the oral glucose tolerance test. Other potential risk factors for type 2 diabetes (e.g., obesity) and its complications (e.g., retinopathy, nephropathy) will be measured. DNA will be collected and analyzed to identify genetic variants associated with or linked to diabetes or other traits. Studies of gene transcription, protein expression and metabolic profiling will be performed, and the resulting patterns will be analyzed for their relationships with diabetes, related traits and variants in diabetes susceptibility genes. Individuals will be studied longitudinally to determine if gene transcription, protein expression and metabolic profiles predict development of diabetes or its complications. These studies will help to determine the molecular pathways between genetic variants and susceptibility to type 2 diabetes and its complications.