The reasons for the epidemics of diabetes and prediabetes, and why individuals from certain populations suffer at higher rates are not well known. In the Pathobiology and Reversibility of Prediabetes in a Biracial Cohort (PROP-ABC) study, nearly 400 African Americans and Caucasians whose parents have type 2 diabetes will undergo repeated testing to determine what factors lead to the occurrence of prediabetes, and whether race still plays a major role in a setting where everyone being studied has one or both parents with diabetes. The PROP-ABC Study also will test the hypothesis that the ability of intensive lifestyle intervention to reverse prediabetes and return people's metabolism back to normal is dependent on how long people have had prediabetes.
Inclusion Criteria: * As planned these studies will enroll interested persons from among the group of 376 subjects who participated in the Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) study between 2006 and 2012. That group includes 267 women and 109 men; 217 are African Americans and 159 are Caucasians. At the time of initial enrollment into POP-ABC, these participants were selected for being nondiabetic offspring of parents with type 2 diabetes. Race and ethnicity was by self-report of non-Hispanic white or non-Hispanic black heritage, and their age range was 18-65 years at enrollment. No new subjects will be recruited into this established cohort. To be eligible for inclusion in the renewal study, subjects must be ambulatory, be in good general health, and must not be taking medications known to alter insulin sensitivity, insulin secretion, or body weight. Exclusion Criteria: * Exclusion criteria: Persons not enrolled in POP-ABC study; diagnosis of diabetes or use of any antidiabetic medication; medical conditions that preclude participation in physical activity; history of liposuction, surgical weight reduction; use of glucocorticoids, beta-blockers, thiazide diuretics (\> 25 mg/day), or medication known to alter glucose metabolism. Women who are pregnant or become pregnant while participating in this study will have all testing procedures delayed until 12 months after delivery.