Racial and etiopathologic dichotomies in insulin hypersecretion and resistance in obese children

Objectives To assess insulin dynamics to oral glucose tolerance testing in obese children, denoting individual contributions of insulin hypersecretion versus resistance to racial and etiopathogenetic specificity. Study design We performed 3-hour oral glucose tolerance testing in 113 nondiabetic obese children (age 13.6 +/- 3.1 years; 41 male, 78 female; 37 black, 41 white; 35 with central nervous system [CNS] insult). The corrected insulin response (CIRgp; measuring beta-cell secretion) and the composite insulin sensitivity, index (CISI) were computed and log-transformed,and each was modeled in terms of the other. plus race/etiology, age, sex, bode, mass index z score, glucose tolerance, pubertal status, and geographic location. Results A scatterplot of logCIRgp versus l ogCISI showed that racial and etiopathogenetic groups plotted indifferent areas. CISI (controlled for CIRgp and other variables) was only 13% lower in blacks than in whites (P = .32). Conversely, CIRgp (controlled for CISI and other variables) was 49% higher in blacks (P = .028). CNS insult exhibited a 40% higher CIRgp (P = .054) and 11% higher CISI (P = .42) than intact white subjects. Conclusions Insulin hypersecretion and resistance are distinct phenomena in childhood obesity. Insulin hypersecretion appears to be the more relevant insulin abnormality both in obese blacks and in CNS insult.