Differential impact of obesity on glucose metabolism in black and white American adolescents

Background: The authors have previously demonstrated abnormalities in gluco se and insulin metabolism in nondiabetic black American (BA) adults versus white American (WA) adults. Whether similar glucoregulatory alterations ext end to BA adolescents remain unknown. In addition, obesity, a known risk fa ctor for insulin resistance and hyperinsulinemia, occurs in a greater propo rtion of BA adults and children when compared to WA. The objective of the p resent study was to examine the differential effects of obesity on glucose homeostasis in BA and WA adolescents. Methods: We examined glucose homeostasis in BA and WA adolescents using ora l glucose tolerance test (OGTT), intravenous glucose tolerance test (IVGTT) , and [6,6-H-2]-glucose infusion. The study consisted of four age-, sex-, a nd pubertal stage-matched groups: 15 lean BA, 29 lean WA, 7 obese BA, and 9 obese WA Results: Both obese groups had significantly increased insulin and C-peptid e area under the curve (AUC) during OGTT and IVGTT when compared to their s ame-race lean counterparts. During OGTT, obese BA demonstrated greater insu lin and C-peptide when compared to obese Wk During IVGTT, first- and second phase insulin were significantly greater in obese BA versus obese WA. Conclusion: In summary, BA adolescents demonstrated insulin resistance whic h is markedly exaggerated in the face of obesity when compared to WA adoles cents, implying a differential impact for obesity on glucose homeostasis th at is unique to the obese BA adolescent group. In conclusion, there is a ne ed for early aggressive weight management in obese BA adolescents.