Race differences in the association of oxidative stress with insulin sensitivity in African- and European-American women.

Academic Article

Abstract

  • Excessive metabolism of glucose and/or fatty acids may impair insulin signaling by increasing oxidative stress. The objective of this study was to examine the association between insulin sensitivity and protein carbonyls, a systemic marker of oxidative stress, in healthy, nondiabetic women, and to determine if the relationship differed with race. Subjects were 25 African-Americans (AA, BMI 28.4 ± 6.2 kg/m(2), range 18.8-42.6 kg/m(2); age 33.1 ± 13.5 years, range 18-58 years) and 28 European-Americans (EA, BMI 26.2 ± 5.9 kg/m(2), range 18.7-48.4 kg/m(2); age 31.6 ± 12.4 years, range 19-58 years). Insulin sensitivity was determined using an intravenous glucose tolerance test incorporating [6,6-(2)H(2)]-glucose, and a two-compartment mathematical model. Multiple linear regression results indicated that insulin sensitivity was inversely associated with protein carbonyls in AA (standardized regression coefficient -0.47, P < 0.05) but not EA (0.01, P = 0.945), after adjusting for %body fat. In contrast, %body fat was significantly and positively associated with insulin sensitivity in EA (-0.54, P < 0.01) but not AA (-0.24, P = 0.196). Protein carbonyls were associated with free fatty acids (FFA) in AA (r = 0.58, P < 0.01) but not EA (r = -0.11, P = 0.59). When subjects were divided based on median levels of fasting glucose and FFA, those with higher glucose/FFA concentrations had a significantly greater concentration of circulating protein carbonyls compared to those with lower glucose/FFA concentrations (P < 0.05). These results suggest that oxidative stress independently contributes to insulin sensitivity among AA women. Further, this association in AA may be mediated by circulating FFA and/or glucose.
  • Published In

  • Obesity Research  Journal
  • Keywords

  • Adolescent, Adult, African Americans, Biomarkers, Blood Glucose, Body Mass Index, European Continental Ancestry Group, Fatty Acids, Nonesterified, Female, Glucose Tolerance Test, Humans, Insulin Resistance, Middle Aged, Models, Theoretical, Oxidative Stress, Protein Carbonylation, United States, Young Adult
  • Digital Object Identifier (doi)

    Author List

  • Fisher G; Alvarez JA; Ellis AC; Granger WM; Ovalle F; Man CD; Cobelli C; Gower BA
  • Start Page

  • 972
  • End Page

  • 977
  • Volume

  • 20
  • Issue

  • 5