Visual Abstract
Studies suggest that Indian Americans (IA) living in US have higher basal insulin resistance than other ethnic groups thereby increasing risk for T2DM. To characterize glucose metabolism between IA to Indians (I) living in India, we studied thirty-one Indians recruited at the Chellaram Hospital in Pune, India and twenty Indian Americans at Mayo Clinic, MN. All underwent a 3-hour 9-point OGTT with analyses of glucose, insulin and C-peptide. The oral minimal model was used to estimate β-cell function (φtotal) and insulin sensitivity (SI), with assessment of β-cell responsivity (Disposition Index: DI). Insulin clearance was calculated as AUC of insulin secretion rate over insulin concentrations. Both I and IA were similar with respect to age (33±7 vs. 39±13y), BMI (25.0±1.8 vs. 24.7± 3.2kg/m2) and sex (13F and 9F) respectively. Results are in fig 1. Fasting and iAUC glucose did not differ between groups (p=0.478), while integrated C-peptide and Insulin concentrations were higher in I than IA (p<0.001). Conversely, DI was higher in IA than I (p=0.045), due to higher insulin clearance (p=0.036) and beta-cell function [φtot] (p=0.040) in the absence of changes in insulin sensitivity. We conclude that these intriguing differences observed in Indian Americans and Indians are novel. Further studies are required to tease out the factors responsible for these differences.
V. Purandare: None. A. Galderisi: None. M. Maertino: None. A. Basu: None. C. Cobelli: None. A. Unnikrishnan: Advisory Panel; Self; Sanofi-Aventis, Other Relationship; Self; Novo Nordisk A/S, Speaker’s Bureau; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Lilly Diabetes. R. Basu: None.
National Institutes of Health (R01DK029953 to R.B.), (R01DK085516 to A.B.)