Racial Differences in Insulin Resistance, Secretion, and Clearance

Abstract

Hispanics and Asians have a higher risk for type 2 diabetes than non-Hispanic whites (NHW); however, the mechanisms remain unclear. We evaluated differences in insulin physiology and the relationship between obesity and insulin action between NHWs (n=68) compared with Hispanics (n=33) and Asians (n=36). All participants were part of our ongoing registry. All were nondiabetic and had the following measurements: 1) insulin resistance (steady-state plasma glucose, SSPG, using the insulin suppression test, IST); 2) insulin secretion rate (using the graded-glucose infusion test, GGIT); and 3) insulin clearance rate (GGIT). Relationships were compared between measures of obesity (BMI, waist circumference) and SSPG, and between SSPG and insulin secretion rate and clearance rate using multivariate regression. Compared with NHWs, both Hispanics and Asians had higher degrees of insulin resistance than predicted by BMI or WC (Figure, p<0.01). Thus, to achieve the same SSPG concentration, the BMI equivalent of 30 kg/m2 in NHWs was 26 in Hispanics and Asians. Insulin secretion and clearance rates were similar for degree of insulin resistance. In conclusion, higher risk for diabetes in Hispanics and Asians may relate to greater risk for obesity-associated insulin resistance. Disclosure S.H. Kim: None.