Insulin resistance predicts future deterioration of glucose tolerance in nondiabetic young African Americans.

Insulin resistance has been linked to the development of type 2 diabetes mellitus and increased cardiovascular risk in several high-risk populations. The purpose of this study was to determine if insulin resistance measured by insulin clamp can predict deterioration of glucose metabolism and increased cardiovascular risk in nondiabetic young adult African Americans. Nondiabetic young African American men (n = 60) and women (n = 114) were enrolled. Measurements obtained included blood pressure, anthropometrics, plasma lipids, oral glucose tolerance test, and insulin sensitivity by insulin clamp. Participants were reexamined 8 years later. The relationship between insulin sensitivity and glucose metabolism was analyzed using a 2-way analysis of variance with body mass index at the initial examination as a covariate. After adjusting for the significant difference of body mass index between the insulin-resistant and insulin-sensitive groups, insulin resistance predicted statistically significant worsening glucose metabolism, developing diabetes, and increasing risk factors for cardiovascular disease.