Background: To determine the role of ethnicity vs. heredity in glucoregulation, we assessed insulin secretion in healthy Black and White offspring of parents with T2DM.
Methods: Participants were screened with 75-g OGTT, and normoglycemic enrollees underwent assessments, including anthropometry, insulin sensitivity and secretion. Basal insulin secretion (fasting insulin {FI} and HOMA-B) and dynamic secretion (insulinogenic index; corrected insulin response {CIR} from OGTT data; acute insulin response to i.v. glucose {AIR}, insulin-AUC during FSIGT, and disposition index {DI} were quantified. Insulin sensitivity (ISI) was measured with euglycemic clamp. Basal insulin clearance (molar ratio of fasting C-peptide to insulin) and dynamic clearance (molar ratio of plasma C-peptide to insulin levels during FSIGT) were determined.
Results: We studied 145 Black and 123 White adults (N=268); 72% women; mean age 44.6±10.1 y. At baseline, fasting glucose (91.0 ± 7.26 vs.93.1 ± 6.31 mg/dl, P=0.012) and ISI (0.062 ± 0.048 vs. 0.077 ± 0.04, P=.014) were lower, and BMI (31.6 ± 7.64 vs. 28.9 ± 6.79, P=.0032) higher, in Black vs. White subjects. Basal insulin secretion was similar, but all measures of dynamic secretion were higher in Black vs. White offspring (Table 1).
Conclusions: Insulin clearance is lower but dynamic insulin secretion is greater in Black versus White individuals with parental diabetes.
P. Asuzu: None. A. Patel: None. J. Y. Wan: None. S. Dagogo-jack: None.
